CAPPED POLY(PHENYLENE ETHER) AND CURABLE THERMOSETTING COMPOSITION COMPRISING THE SAME CROSS-REFERENCE TO RELATED APPLICATION This application claims priority to and the benefit of European Patent Application No. 22151118.1, filed on January 12, 2022, the contents of which are incorporated by reference herein in their entirety. BACKGROUND [0001] This disclosure relates to a capped poly(phenylene ether), a curable thermosetting composition including the same, and articles derived therefrom. [0002] Thermosetting resins are materials that cure to form extremely hard plastics. These materials that can be used in a wide variety of consumer and industrial products. For example, thermosets are used in protective coatings, adhesives, electronic laminates (such as those used in the fabrication of computer circuit boards), flooring, and paving applications, glass fiber-reinforced pipes, and automotive parts (including leaf springs, pumps, and electrical components). [0003] Poly(phenylene ether)s can improve dielectric performance, heat resistance, flame resistance and moisture absorption of thermoset materials, making them particularly well suited for a variety of applications, particularly electronic applications. [0004] It would therefore be advantageous to provide a poly(phenylene ether) for use in curable thermosetting compositions. SUMMARY [0005] A capped poly(phenylene ether) has the structure or wherein Z ¹ , Z ² , Z ³ , and Z ⁴ each independently comprise hydrogen, halogen, unsubstituted or substituted C1-12 primary or secondary hydrocarbyl, C1-12 hydrocarbylthio, C1-12 hydrocarbyloxy, and C ₂ - ₁₂ halohydrocarbyloxy wherein at least two carbon atoms separate the halogen and oxygen atoms; R ¹ is a substituted or unsubstituted phenylene group; R ² is a substituted or unsubstituted C _6-20 aromatic hydrocarbon group; n is an integer from 4 to 50; x and y are each independently zero to 50, provided that the sum of x and y is 2 to 53; and L is a group of the formula wherein each occurrence of R ³ , R ⁴ , R ⁵ , and R ⁶ independently comprises hydrogen, halogen, unsubstituted or substituted C1-12 primary or secondary hydrocarbyl, C1-12 hydrocarbylthio, C1-12 hydrocarbyloxy, or C2-12 halohydrocarbyloxy wherein at least two carbon atoms separate the halogen and oxygen atoms; z is 0 or 1; and Y has a structure comprising , wherein each occurrence of R ⁷ independently comprises hydrogen and C1-12 hydrocarbyl, and each occurrence of R ⁸ and R ⁹ is each independently hydrogen, C1-12 hydrocarbyl, or C1-6 hydrocarbylene wherein R ⁸ and R ⁹ collectively form a C4-12 alkylene group, or Y has a structure derived from a hydroxyaryl-diterminated polysiloxane. [0006] A curable thermosetting composition comprises the capped poly(phenylene ether). [0007] A cured thermoset composition comprising a cured product of the curable thermosetting composition. [0008] An article comprises the cured thermoset composition. [0009] The above described and other features are exemplified by the following detailed description. DETAILED DESCRIPTION [0010] The present inventor has discovered that capped poly(phenylene ether)s can be prepared having an activated ester end group. The capped poly(phenylene ether)s can advantageously be used to provide a curable thermosetting composition having a desirable combination of dielectric properties, flame resistance, and heat performance. [0011] Accordingly, an aspect of the present disclosure is a capped poly(phenylene ether). The capped poly(phenylene ether) comprises repeating units derived from a substituted or unsubstituted monohydric phenol. The substituted or unsubstituted monohydric phenol can have the structure wherein Z ¹ , Z ² , Z ³ , and Z ⁴ each independently comprise hydrogen, halogen, unsubstituted or substituted C1-12 primary or secondary hydrocarbyl, C1-12 hydrocarbylthio, C1-12 hydrocarbyloxy, and C ₂ - ₁₂ halohydrocarbyloxy wherein at least two carbon atoms separate the halogen and oxygen atoms. In an aspect, the substituted or unsubstituted monohydric phenol comprises a 2,6-(di-C _1-6 alkyl) phenol. In an aspect, Z ¹ and Z ⁴ are each methyl and Z ² and Z ³ are each hydrogen, and the monohydric phenol is 2,6-xylenol (also referred to as 2,6- dimethylphenol or “DMP”). [0012] The capped poly(phenylene ether) therefore comprises repeating units of the formula wherein Z ¹ , Z ² , Z ³ , and Z ⁴ can be as described above. In an aspect, the capped poly(phenylene ether) can comprise repeating units derived from a monohydric phenol comprising a 2,6-(di-C1- ₁₈ alkyl) phenol, or 2,6-diphenylphenol, a 2-phenyl-6-(C _1-18 alkyl) phenol, 2-phenyl-6- (cycloalkyl) phenol, 2,6-(dicycloalkyl) phenol, 2-(C1-18 alkyl)-6-(cycloalkyl) phenol, or a combination thereof. In an aspect, the capped poly(phenylene ether) comprises repeating units derived from 2,6-dimethylphenol. [0013] The capped poly(phenylene ether) comprises at least one activated ester end group of the formula wherein R ¹ is a substituted or unsubstituted phenylene group and R ² is a substituted or unsubstituted C _6-20 aromatic hydrocarbon group, and the “*” indicates the point of attachment of the activated ester end group to the poly(phenylene ether). [0014] In an aspect, the capped poly(phenylene ether) has the structure wherein Z ¹ , Z ² , Z ³ , Z ⁴ , R ¹ and R ² can be as described above, and n is an integer from 4 to 50. In an aspect, Z ² and Z ³ are each hydrogen and Z ¹ and Z ⁴ are each an unsubstituted or substituted C1-12 primary hydrocarbyl. In an aspect, Z ¹ and Z ⁴ are each a C1-6 alkyl group, for example a methyl group. In an aspect, R ¹ is an unsubstituted phenylene group. In an aspect, R ¹ is derived from terephthalic acid or isophthalic acid. In an aspect, R ² comprises a phenyl group, a methyl- substituted phenyl group, a dimethyl-substituted phenyl group, a phenyl-substituted phenyl group, a benzyl-substituted phenyl group, a cumyl-substituted phenyl group, or a naphthyl group, preferably a phenyl group or a naphthyl group. [0015] In an aspect, the capped poly(phenylene ether) can have the structure , , , or , wherein Z ¹ , Z ² , Z ³ , Z ⁴ and n can be as described above, and n is an integer from 4 to 50. [0016] In an aspect, the capped poly(phenylene ether) can have the structure

, , , or , wherein n is an integer from 4 to 50. [0017] In an aspect, the capped poly(phenylene ether) has the structure wherein Z ¹ , Z ² , Z ³ , Z ⁴ , R ¹ and R ² can be as described above, and x and y are each independently zero to 50, provided that the sum of x and y is 2 to 53. In an aspect, Z ² and Z ³ are each hydrogen and Z ¹ and Z ⁴ are each an unsubstituted or substituted C ₁ - ₁₂ primary hydrocarbyl. In an aspect, Z ¹ and Z ⁴ are each a C1-6 alkyl group, for example a methyl group. In an aspect, R ¹ is an unsubstituted phenylene group. In an aspect, R ¹ is derived from terephthalic acid or isophthalic acid. In an aspect, R ² comprises a phenyl group, a methyl-substituted phenyl group, a dimethyl-substituted phenyl group, a phenyl-substituted phenyl group, a benzyl-substituted phenyl group, a cumyl-substituted phenyl group, or a naphthyl group, preferably a phenyl group or a naphthyl group. [0018] L can be a group of the formula wherein each occurrence of R ³ , R ⁴ , R ⁵ , and R ⁶ independently comprises hydrogen, halogen, unsubstituted or substituted C ₁ - ₁₂ primary or secondary hydrocarbyl, C ₁ - ₁₂ hydrocarbylthio, C ₁ - ₁₂ hydrocarbyloxy, or C2-12 halohydrocarbyloxy wherein at least two carbon atoms separate the halogen and oxygen atoms; z is 0 or 1; and Y has a structure comprising , wherein each occurrence of R ⁷ independently comprises hydrogen and C1-12 hydrocarbyl, and each occurrence of R ⁸ and R ⁹ is each independently hydrogen, C ₁ - ₁₂ hydrocarbyl, or C ₁ - ₆ hydrocarbylene wherein R ⁸ and R ⁹ collectively form a C4-12 alkylene group. For example, R ⁸ and R ⁹ can collectively form a cyclohexylidene group. [0019] In an aspect, L can be a group derived from a hydroxyaryl-diterminated polysiloxane. When L is derived from a hydroxyaryl-terminated polysiloxane, the poly(phenylene ether) can be referred to as a poly(phenylene ether)-siloxane block copolymer having at least one poly(phenylene ether) block and at least one polysiloxane block. [0020] The hydroxyaryl-diterminated polysiloxane can comprise a plurality of repeating units having the structure wherein each occurrence of R ¹⁰ is independently hydrogen, C _1-12 hydrocarbyl or C _1-12 halohydrocarbyl. The hydroxyaryl-diterminated polysiloxane further comprises two terminal units having the structure wherein Y is hydrogen, C1-12 hydrocarbyl, C1-12 hydrocarbyloxy, or halogen, and wherein each occurrence of R ¹¹ is independently hydrogen, C _1-12 hydrocarbyl or C _1-12 halohydrocarbyl. In an aspect, each occurrence of R ¹⁰ and R ¹¹ is methyl, and Y is methoxy. [0021] In an aspect, the hydroxyaryl-terminated polysiloxane has the structure wherein m is, on average, 5 to 100, or 5 to 45, or 30 to 60. [0022] In an aspect, R ³ and R ⁴ are not hydrogen. In an aspect, R ³ and R ⁴ are each a C _1-6 alkyl group, preferably a methyl group, and R ⁵ and R ⁶ are each hydrogen. In a specific aspect, each occurrence of R ³ and R ⁴ is methyl, each occurrence of R ⁵ and R ⁶ is hydrogen, z is 1, and Y is an isopropylidene group. In an aspect, each occurrence of R ³ and R ⁴ is methyl, each occurrence of R ⁵ and R ⁶ is hydrogen, z is 1, and Y is an isopropylidene group and Z ² and Z ³ are each hydrogen and Z ¹ and Z ⁴ are each an unsubstituted or substituted C1-12 primary hydrocarbyl, preferably methyl. [0023] In an aspect, the capped poly(phenylene ether) can have the structure , , , or , wherein Z ¹ , Z ² , Z ³ , Z ⁴ , L, x and y can be as defined above. [0024] In an aspect, the capped poly(phenylene ether) can have the structure , , , or , wherein L, x and y can be as defined above. [0025] In an aspect, the capped poly(phenylene ether) can have the structure , wherein x, y, R ¹ and R ² can be as defined above. In an aspect, R ¹ is a divalent phenylene group; and R ² is a phenyl group or a naphthyl group. [0026] The poly(phenylene ether) can have a number average molecular weight of less than 20,000 grams per mole, or less than 10,000 grams per mole, or less than 7,500 grams per mole. For example, the poly(phenylene ether) can have a number average molecular weight of 500 to 20,000 g/mol, or 500 to 10,000 g/mol, or 500 to 7,500 g/mol. Molecular weight can be determined by gel permeation chromatography (GPC) relative to polystyrene standards or can be calculated from the degree of polymerization determined using nuclear magnetic resonance (NMR) spectroscopy. [0027] The poly(phenylene ether) can have an intrinsic viscosity of less than or equal to 0.15 deciliters per gram, preferably 0.02 to 0.15 deciliters per gram, more preferably 0.12 to 0.13 deciliters per gram. Intrinsic viscosity can be determined at 25°C in chloroform by Ubbelohde viscometer. [0028] The capped poly(phenylene ether) can be made by a method comprising oxidatively polymerizing the monohydric phenol in the presence of a catalyst, and optionally a dihydric phenol, to provide a poly(phenylene ether) having a phenolic end group. The oxidative polymerization can be conducted in the presence of an organic solvent. Suitable organic solvents can include alcohols, ketones, aliphatic and aromatic hydrocarbons, chlorohydrocarbons, nitrohydrocarbons, ethers, esters, amides, mixed ether-esters, sulfoxides, and the like, provided they do not interfere with or enter into the oxidation reaction. High molecular weight poly(phenylene ethers) can greatly increase the viscosity of the reaction mixture. Therefore, it is sometimes desirable to use a solvent system that will cause them to precipitate while permitting the lower molecular weight polymers to remain in solution until they form the higher molecular weight polymers. The organic solvent can comprise, for example, toluene, benzene, chlorobenzene, ortho-dichlorobenzene, nitrobenzene, trichloroethylene, ethylene dichloride, dichloromethane, chloroform, or a combination thereof. Preferred solvents include aromatic hydrocarbons. In an aspect, the organic solvent comprises toluene, benzene, xylene, chloroform, chlorobenzene, or a combination thereof, preferably toluene. [0029] The oxidative polymerization is further conducted in the presence of a copper- amine catalyst. The copper source for the copper amine catalyst can comprise a salt of cupric or cuprous ion, including halides, oxides and carbonates. Alternatively, copper can be provided in the form of a pre-formed salt of an alkylene diamine ligand. Preferred copper salts include cuprous halides, cupric halides, and their combinations. Especially preferred are cuprous bromides, cupric bromides, and combinations thereof. [0030] A preferred copper-amine catalyst comprises a secondary alkylene diamine ligand. Suitable secondary alkylene diamine ligands are described in U.S. Pat. No.4,028,341 to Hay and are represented by the formula R ^b —NH—R ^a —NH—R ^c wherein R ^a is a substituted or unsubstituted divalent residue wherein two or three aliphatic carbon atoms form the closest link between the two diamine nitrogen atoms; and R ^b and R ^c are each independently isopropyl or a substituted or unsubstituted C _4-8 tertiary alkyl group. Examples of R ^a include ethylene, 1,2-propylene, 1,3-propylene, 1,2-butylene, 1,3-butylene, 2,3- butylene, the various pentylene isomers having from two to three carbon atoms separating the two free valances, phenylethylene, tolylethylene, 2-phenyl-1,2-propylene, cyclohexylethylene, 1,2-cyclohexylene, 1,3-cyclohexylene, 1,2-cyclopropylene, 1,2-cyclobutylene, 1,2- cyclopentylene, and the like. Preferably, R ^a is ethylene. Examples of R ^b and R ^c can include isopropyl, t-butyl, 2-methyl-but-2-yl, 2-methyl-pent-2-yl, 3-methyl-pent-3-yl, 2,3-dimethyl-but- 2-yl, 2,3-dimethylpent-2-yl, 2,4-dimethyl-pent-2-yl, 1-methylcyclopentyl, 1-methylcyclohexyl and the like. A highly preferred example of R ^b and R ^c is t-butyl. An exemplary secondary alkylene diamine ligand is N,N'-di-t-butylethylenediamine (DBEDA). Suitable molar ratios of copper to secondary alkylene diamine are from 1:1 to 1:5, preferably 1:1 to 1:3, more preferably 1:1.5 to 1:2. [0031] The preferred copper-amine catalyst comprising a secondary alkylene diamine ligand can further comprise a secondary monoamine. Suitable secondary monoamine ligands are described in commonly assigned U.S. Pat. No.4,092,294 to Bennett et al. and represented by the formula R ^d —NH—R ^e wherein R ^d and R ^e are each independently substituted or unsubstituted C1-12 alkyl groups, and preferably substituted or unsubstituted C _3-6 alkyl groups. Examples of the secondary monoamine include di-n-propylamine, di-isopropylamine, di-n-butylamine, di-sec-butylamine, di-t-butylamine, N-isopropyl-t-butylamine, N-sec-butyl-t-butylamine, di-n-pentylamine, bis(1,1- dimethylpropyl)amine, and the like. A highly preferred secondary monoamine is di-n- butylamine (DBA). A suitable molar ratio of copper to secondary monoamine is from 1:1 to 1:10, preferably 1:3 to 1: 8, and more preferably 1:4 to 1:7. [0032] The preferred copper-amine catalyst comprising a secondary alkylene diamine ligand can further comprise a tertiary monoamine. Suitable tertiary monoamine ligands are described in the abovementioned Hay U.S. Pat. No.4,028,341 and Bennett U.S. Pat. No. 4,092,294 patents and include heterocyclic amines and certain trialkyl amines characterized by having the amine nitrogen attached to at least two groups which have a small cross-sectional area. In the case of trialkylamines, it is preferred that at least two of the alkyl groups be methyl with the third being a primary C _1-8 alkyl group or a secondary C _3-8 alkyl group. It is especially preferred that the third substituent have no more than four carbon atoms. A highly preferred tertiary amine is dimethylbutylamine (DMBA). A suitable molar ratio of copper to tertiary amine is less than 1:20, preferably less than 1:15, preferably 1:1 to less than 1:15, more preferably 1:1 to 1:12. [0033] A suitable molar ratio of copper-amine catalyst (measured as moles of metal) to poly(phenylene ether) starting material is 1:50 to 1:400, preferably 1:100 to 1:200, more preferably 1:100 to 1:180. [0034] The reaction conducted in the presence of a copper-amine catalyst can optionally be conducted in the presence of bromide ion. It has already been mentioned that bromide ion can be supplied as a cuprous bromide or cupric bromide salt. Bromide ion can also be supplied by addition of a 4-bromophenol, such as 2,6-dimethyl-4-bromophenol. Additional bromide ion can be supplied in the form of hydrobromic acid, an alkali metal bromide, or an alkaline earth metal bromide. Sodium bromide and hydrobromic acid are highly preferred bromide sources. A suitable ratio of bromide ion to copper ion is 2 to 20, preferably 3 to 20, more preferably 4 to 7. [0035] In an aspect, each of the above-described components of the copper-amine catalyst are added to the oxidative polymerization reaction at the same time. [0036] The oxidative polymerization can optionally further be conducted in the presence of one or more additional components, including a lower alkanol or glycol, a small amount of water, or a phase transfer agent. It is generally not necessary to remove reaction byproduct water during the reaction. [0037] In an aspect, a phase transfer agent is present. Suitable phase transfer agents can include, for example, a quaternary ammonium compound, a quaternary phosphonium compound, a tertiary sulfonium compound, or a combination thereof. Preferably, the phase transfer agent can be of the formula (R ³ )4Q ⁺ X, wherein each R ³ is the same or different, and is a C _1-10 alkyl; Q is a nitrogen or phosphorus atom; and X is a halogen atom or a C _1-8 alkoxy or C _6-18 aryloxy. Exemplary phase transfer catalysts include (CH3(CH2)3)4NX, (CH3(CH2)3)4PX, (CH ₃ (CH ₂ ) ₅ ) ₄ NX, (CH ₃ (CH ₂ ) ₆ ) ₄ NX, (CH ₃ (CH ₂ ) ₄ ) ₄ NX, CH ₃ (CH ₃ (CH ₂ ) ₃ ) ₃ NX, and CH3(CH3(CH2)2)3NX, wherein X is Cl-, Br-, a C1-8 alkoxy or a C6-18 aryloxy. An effective amount of a phase transfer agent can be 0.1 to 10 wt%, or 0.5 to 2 wt%, each based on the weight of the reaction mixture. In an aspect, a phase transfer agent is present and comprises N,N,N’N’-didecyldimethyl ammonium chloride. [0038] The oxidative polymerization can be conducted at a temperature of 20 to 70°C, preferably 30 to 60°C, more preferably 45 to 55°C. Depending on the precise reaction conditions chosen, the total polymerization reaction time—that is, the time elapsed between initiating oxidative polymerization and terminating oxidative polymerization—can vary, but it is typically 100 to 250 minutes, specifically 145 to 210 minutes. [0039] The method further comprises terminating the oxidative polymerization to form a post-termination reaction mixture. The reaction is terminated when the flow of oxygen to the reaction vessel is stopped. Residual oxygen in the reaction vessel headspace is removed by flushing with an oxygen-free gas, such as nitrogen. [0040] After the polymerization reaction is terminated, the copper ion of the polymerization catalyst is separated from the reaction mixture. This is accomplished by combining a chelant with the post-termination reaction mixture to form a chelation mixture. The chelant comprises an alkali metal salt of an aminopolycarboxylic acid, preferably an alkali metal salt of an aminoacetic acid, more preferably an alkali metal salt of nitrilotriacetic acid, ethylene diamine tetraacetic acid, or a combination thereof, even more preferably a sodium salt of nitrilotriacetic, a sodium salt of ethylene diamine tetraacetic acid, or a combination thereof. In an aspect, the chelant comprises an alkali metal salt of nitrilotriacetic acid. In an aspect, the chelant is a sodium or potassium salt of nitrilotriacetic acid, specifically trisodium nitrilotriacetate. After agitation of the chelation mixture, that mixture comprises an aqueous phase comprising chelated copper ion and an organic phase comprising the dissolved poly(phenylene ether). The chelation mixture can exclude the dihydric phenol required by U.S. Pat. No.4,110.311 to Cooper et al., the aromatic amine required by U.S. Pat. No.4,116,939 to Cooper et al., and the mild reducing agents of U.S. Pat. No.4,110.311 to Cooper et al., which include sulfur dioxide, sulfurous acid, sodium bisulfite, sodium thionite, tin(II) chloride, iron (II) sulfate, chromium (II) sulfate, titanium (III) chloride, hydroxylamines and salts thereof, phosphates, glucose, and mixtures thereof. The chelation mixture is maintained at a temperature of 40 to 55°C, specifically 45 to 50°C, for 5 to 100 minutes, specifically 10 to 60 minutes, more specifically 15 to 30 minutes. This combination of temperature and time is effective for copper sequestration while also minimizing molecular weight degradation of the poly(phenylene ether). The chelation step includes (and concludes with) separating the aqueous phase and the organic phase of the chelation mixture. This separation step can be conducted at a temperature of 40 to 55°C, specifically 45 to 50°C. The time interval of 5 to 100 minutes for maintaining the chelation mixture at 40–55°C is measured from the time at which the post-termination reaction mixture is first combined with chelant to the time at which separation of the aqueous and organic phases is complete. [0041] The method further comprises reacting the poly(phenylene ether) with a capping agent under conditions effective to provide the capped poly(phenylene ether). Suitable capping agents can be selected to provide the desired capped poly(phenylene ether) without undue experimentation and guided by the present disclosure. An exemplary method for the manufacture of a capped poly(phenylene ether) is provided in the examples below. [0042] Also provided is a curable thermosetting composition including the capped poly(phenylene ether). For example, the capped poly(phenylene ether) can be present in the curable thermosetting composition in an amount of 1 to 95 weight percent (wt%), or 5 to 95 wt%, or 10 to 85 wt%, or 20 to 80 wt%, 30 to 70 wt%, or 5 to 30 wt%, or 5 to 15 wt%, based on the total weight of the curable thermosetting composition. [0043] The curable thermosetting composition can further include one or more of a crosslinking agent, a curing agent, a curing catalyst, a curing initiator, or a combination thereof. In an aspect, the curable thermosetting composition can further include one or more of a flame retardant, a filler, a coupling agent, or a combination thereof. For example, the curable thermosetting composition can include one or more of a crosslinking agent, a curing agent, a curing catalyst, a curing initiator, or a combination thereof; and can further include one or more of a flame retardant, a filler, a coupling agent, or a combination thereof. [0044] There is considerable overlap among thermosetting resins, crosslinking agents, and coupling agents. As used herein, the term “crosslinking agent” includes compounds that can be used as thermosetting resins, crosslinkers, coupling agents, or a combination thereof. For example, in some instances a compound that is a thermosetting resin could also be used as a crosslinking agent, a coupling agent, or both. [0045] The thermosetting resins are not particularly limited, and thermosetting resins can be used alone or in combinations of two or more thermosetting resins (e.g., including one or more auxiliary thermosetting resins). Exemplary thermosetting resins include epoxy resins, cyanate ester resins, (bis)maleimide resins, (poly)benzoxazine resins, vinyl resins (e.g., a vinyl benzyl ether resin), phenolic resins, alkyd resins, unsaturated polyester resins, arylcyclobutene resins, perfluorovinyl ether resins, monomers, oligomers or polymers with curable unsaturation (e.g., a vinyl functionality), or the like, or a combination thereof. [0046] In an aspect, the curable thermosetting composition comprises the capped poly(phenylene ether) and an epoxy resin. [0047] The epoxy resin can generally be any epoxy resin that is suitable for use in thermosetting resins. The term “epoxy resin” in this context refers to a curable composition of oxirane ring-containing compounds as described in, for example, C. A. May, Epoxy Resins, 2.sup.nd Edition, (New York & Basle: Marcel Dekker Inc.), 1988. The epoxy resins can include bisphenol A type epoxy resins such as those obtained from bisphenol A and resins obtained by substituting at least one position of the 2-position, the 3-position and the 5-position of bisphenol A with a halogen atom, an alkyl group having 6 or less carbon atoms or a phenyl group; bisphenol F type epoxy resins such as those obtained from bisphenol F and a resin obtained by substituting at least one position of the 2-position, the 3-position and the 5-position of bisphenol F with a halogen atom, an alkyl group having 6 or less carbon atoms or a phenyl group; glycidyl ether compounds derived from bivalent or tri- or more-valent phenols such as hydroquinone, resorcinol, tris-4-(hydroxyphenyl)methane and 1,1,2,2-tetrakis(4-hydroxyphenyl)ethane; a novolak type epoxy resin derived from a novolak resin which is a reaction product between phenols such as phenol and o-cresol and formaldehyde, including bisphenol A novolak type epoxy resins and cresol novolak type epoxy resins; cyclic aliphatic epoxy compounds such as 2,2-bis(3,4-epoxycyclohexyl)propane, 2,2-bis[4-(2,3-epoxypropyl)cyclohexyl]propane, vinylcyclohexene dioxide, 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexane carboxylate; dicyclopentadiene-containing polyepoxides; amine type epoxy resins derived from aniline, p- aminophenol, m-aminophenol, 4-amino-m-cresol, 6-amino-m-cresol, 4,4^-diaminodiphenyl- ethane, 3,3^-diaminodiphenylmethane, 4,4^-diaminodiphenyl ether, 3,4^-diaminodiphenylether, 1,4-bis(4-aminophenoxy)benzene, 1,4-bis(3-aminophenoxy)-benzene, 1,3-bis(4-aminophenoxy)- benzene, 1,3-bis(3-aminophenoxy)benzene, 2,2-bis(4-amino-phenoxyphenyl)propane, p- phenylenediamine, m-phenylenediamine, 2,4-toluenediamine, 2,6-toluenediamine, p-xylylene- diamine, m-xylylenediamine, 1,4-cyclohexane-bis(methylamine), 5-amino-1-(4^-aminophenyl)- 1,3,3-trimethylindane, 6-amino-1-(4^-aminophenyl)-1,3,3-trimethyl-indane or the like; hetero- cyclic epoxy compounds, and glycidyl ester type epoxy compounds, for example, those derived from glycidyl ester of aromatic carboxylic acids such as p-oxybenzoic acid, m-oxybenzoic acid, terephthalic acid, and isophthalic acid. An “epoxy resin” can also include reaction products of compounds containing two or more epoxy groups and aromatic dihydroxy compounds, which can be optionally halogen-substituted and can be used alone or in a combination of two or more. [0048] Cyanate esters are not limited, and any resin composed of cyanate ester monomers, which polymerize to form a polymer containing a plurality of cyanate ester (-OCN) functional groups can be used. Cyanate ester monomers, prepolymers (i.e., partially polymerized cyanate ester monomers or blends of cyanate ester monomers), homopolymers, and copolymers made using cyanate ester precursors, and combinations of these compounds. For example, cyanate esters can be prepared according to methods as disclosed in “Chemistry and Technology of Cyanate Ester Resins”, by Ian Hamerton, Blackie Academic and Professional; U.S. Pat. No. 3,553,244, and JP-A-7-53497. Exemplary cyanate ester resins include 2,2-bis(4-cyanatophenyl)- propane, bis(4-cyanatophenyl)ethane, bis(3,5-dimethyl-4-cyanatophenyl)methane, 2,2-bis(4- cyanatophenyl)-1,1,1,3,3,3-hexafluoropropane, ^,^^-bis(4-cyanatophenyl)-m-diisopropyl- benzene, cyanate ester resins prepared from dicyclopentadiene-phenol copolymers, and prepolymers prepared from these monomers. An example of a prepolymer is PRIMASET BA- 230S (Lonza). The cyanate ester prepolymers can be homopolymers or can be copolymers that incorporate other monomers. Examples of such copolymers include BT resins available from Mitsubishi Gas Chemical, such as, BT 2160 and BT2170, which are prepolymers made with cyanate ester monomers and bismaleimide monomers. Other cyanate esters polymers, monomers, prepolymers, and blends of cyanate ester monomers with other non-cyanate ester monomers are disclosed in US 7393904, US 7388057, US 7276563, and US 7192651. [0049] Bismaleimide resins can be produced by reaction of a monomeric bismaleimide with a nucleophile such as a diamine, aminophenol, or amino benzhydrazide, or by reaction of a bismaleimide with diallyl bisphenol A. Exemplary bismaleimide resins include 1,2- bismaleimidoethane, 1,6-bismaleimidohexane, 1,3-bismaleimidobenzene, 1,4-bismaleimido- benzene, 2,4-bismaleimidotoluene, 4,4'-bismaleimidodiphenylmethane, 4,4'-bismaleimido- diphenylether, 3,3'-bismaleimidodiphenylsulfone, 4,4'-bismaleimido-diphenylsulfone, 4,4'- bismaleimidodicyclohexylmethane, 3,5-bis(4-maleimidophenyl)pyridine, 2,6-bismaleimido- pyridine, 1,3-bis(maleimidomethyl)cyclohexane, 1,3-bis(maleimidomethyl)benzene, 1,1-bis(4-maleimidophenyl)cyclohexane, 1,3-bis(dichloromaleimido)benzene, 4,4'-bis(citracon- imido)diphenylmethane, 2,2-bis(4-maleimidophenyl)propane, 1-phenyl-1,1-bis(4-maleimido- phenyl)ethane, N,N-bis(4-maleimidophenyl)toluene, 3,5-bismaleimido-1,2,4-triazole N,N'- ethylenebismaleimide, N,N'-hexamethylenebismaleimide, N,N'-m-phenylene-bismaleimide, N,N'-p-phenylenebismaleimide, N,N'-4,4'-diphenylmethanebismaleimide, N,N'-4,4'-diphenyl- etherbismaleimide, N,N'-4,4'-diphenylsufonebismaleimide, N,N'-4,4'-dicyclohexylmethane- bismaleimide, N,N'-α,α'-4,4'-dimethylenecyclohexanebismaleimide, N,N'-m-methaxylene- bismaleimide, N,N'-4,4'-diphenylcyclohexanebismaleimide, and N,N'-methylene-bis(3-chloro- p-phenylene)bismaleimide, as well as those disclosed in US 3,562,223; US 4,211,860; and US 4,211,861, or as prepared by methods as described, for example, in US 3,018,290. [0050] The benzoxazine compounds have a benzoxazine ring in the molecule. Exemplary benzoxazine monomers can be prepared from the reaction of aldehydes, phenols, and primary amines with or without solvent. The phenolic compounds for forming benzoxazines include phenols and polyphenols. The use of polyphenols with two or more hydroxyl groups reactive in forming benzoxazines can result in branched, crosslinked, or a combination of branched and crosslinked products. The groups connecting the phenolic groups into a phenol can be branch points or connecting groups in the polybenzoxazine. [0051] Exemplary phenols for use in the preparation of benzoxazine monomers include phenol, cresol, resorcinol, catechol, hydroquinone, 2-allylphenol, 3-allylphenol, 4-allylphenol, 2,6-dihydroxynaphthalene, 2,7-dihydrooxynapthalene, 2-(diphenyl-phosphoryl)hydroquinone, 2,2’-biphenol, 4,4-biphenol, 4,4’-isopropylidenediphenol, 4,4’-isopropylidenebis(2-methyl- phenol), 4,4’-isopropylidenebis(2-allylphenol), 4,4’(1,3-phenylenediisopropylidene)bisphenol (bisphenol M), 4,4’-isopropylidenebis(3-phenylphenol) 4,4’-(1,4-phenylenediisoproylidene)- bisphenol, 4,4’-ethylidenediphenol, 4,4’-oxydiphenol, 4,4’-thiodiphenol, 4,4’-sufonyldiphenol, 4,4’-sulfinyldiphenol, 4,4’-hexafluoroisopropylidene)bisphenol, 4,4’(1-phenylethylidene)- bisphenol, bis(4-hydroxyphenyl)-2,2-dichloroethylene, bis(4-hydroxyphenyl)methane, 4,4'- (cyclopentylidene)diphenol, 4,4'-(cyclohexylidene)diphenol, 4,4'-(cyclododecylidene)diphenol 4,4'-(bicyclo[2.2.1]heptylidene)diphenol, 4,4'-(9H-fluorene-9,9-diyl)diphenol, isopropylidene- bis(2-allylphenol), 3,3-bis(4-hydroxyphenyl)isobenzofuran-1(3H)-one, 1-(4-hydroxyphenyl)- 3,3-dimethyl-2,3-dihydro-1H-inden-5-ol, 3,3,3',3'-tetramethyl-2,2',3,3'-tetrahydro-1,1'-spirobi- [indene] 5,6'-diol, dihydroxybenzophenone, tris(4-hydroxyphenyl)methane, tris(4-hydroxy- phenyl)ethane, tris(4-hydroxyphenyl)propane, tris(4-hydroxyphenyl)butane, tris(3-methyl-4- hydroxyphenyl)methane, tetrakis(4-hydroxyphenyl)ethane dicyclopentadienylbis(2,6-dimethyl phenol), dicyclopentadienyl bis(ortho-cresol), dicyclopentadienyl bisphenol, or the like. [0052] The aldehydes used to form the benzoxazine can be any aldehyde, such as an aldehyde having 1 to 10 carbon atoms. For example, the aldehyde can be formaldehyde. The amine used to form the benzoxazine can be an aromatic amine, an aliphatic amine, an alkyl substituted aromatic, or an aromatic substituted alkyl amine. The amine can be a polyamine, for example to prepare polyfunctional benzoxazine monomers for crosslinking. [0053] The amines for forming benzoxazines have 1 to 40 carbon atoms unless they include aromatic rings, and then they can have 6 to 40 carbon atoms. The amine of di- or polyfunctional can be a branch point to connect one polybenzoxazine to another. [0054] In some examples, thermal polymerization at 150 to 300° C can be used for polymerizing benzoxazine monomers. The polymerization can be done in bulk, from solution, or otherwise. Catalysts, such as carboxylic acids, can be used to reduce the polymerization temperature or accelerate the polymerization rate at the same temperature. [0055] Vinyl benzyl ether resins can be prepared from condensation of a phenol with a vinyl benzyl halide, such as vinyl benzyl chloride. Bisphenol-A and trisphenols and polyphenols are generally used to produce poly(vinylbenzyl ethers) which can be used to produce crosslinked thermosetting resins. Exemplary vinyl benzyl ethers can include those vinylbenzyl ethers produced from reaction of a vinylbenzyl halide with resorcinol, catechol, hydroquinone, 2,6- dihydroxynaphthalene, 2,7-dihydroxynaphthalene, 2-(diphenyl-phosphoryl)hydroquinone, bis(2,6-dimethylphenol) 2,2’-biphenol, 4,4-biphenol, 2,2’,6,6’-tetramethylbiphenol, 2,2’,3,3’,6,6’-hexamethylbiphenol, 3,3’,5,5’-tetrabromo-2,2’6,6’-tetramethylbiphenol, 3,3’- dibromo-2,2’,6,6’-tetramethylbiphenol, 2,2’,6,6’-tetramethyl-3,3’5-dibromobiphenol, 4,4’-iso- propylidenediphenol, 4,4’-isopropylidenebis(2,6-dibromophenol), 4,4’-isopropylidenebis(2,6- dimethylphenol) (teramethylbisphenol A), 4,4’-isopropylidenebis(2-methylphenol), 4,4’- ispropylidenebis(2-allylphenol), 4,4’(1,3-phenylenediisopropylidene)bisphenol, 4,4’-isopropyli- denebis(3-phenylphenol) 4,4’-(1,4-phenylenediisoproylidene)bisphenol, 4,4’-ethylidenedi- phenol, 4,4’-oxydiphenol, 4,4’-thiodiphenol, 4,4’-thiobis(2,6-dimethylphenol), 4,4’-sufonyldi- phenol, 4,4’-sulfonylbis(2,6-dimethylphenol) 4,4’-sulfinyl-diphenol, 4,4’-hexafluoroisopropyli- dene)bisphenol, 4,4’(1-phenylethylidene) bisphenol, bis(4-hydroxyphenyl)-2,2-dichloro- ethylene, bis(4-hydroxy-phenyl)methane, bis(2,6-dimethyl-4-hydroxyphenyl)methane, 4,4'- (cyclopentylidene)diphenol, 4,4'-(cyclohexylidene)diphenol, 4,4'-(cyclododecylidene)diphenol 4,4'-(bicyclo [2.2.1]heptylidene)diphenol, 4,4'-(9H-fluorene-9,9-diyl)diphenol, 3,3-bis(4- hydroxyphenyl)-isobenzofuran-1(3H)-one, 1-(4-hydroxyphenyl)-3,3-dimethyl-2,3-dihydro-1H- inden-5-ol, 1-(4-hydroxy-3,5-dimethylphenyl)-1,3,3,4,6-pentamethyl-2,3-d ihydro-1H-inden-5- ol, 3,3,3',3'-tetramethyl-2,2',3,3'-tetrahydro-1,1'-spirobi[inde ne]-5,6'-diol, dihydroxybenzo- phenone, tris(4-hydroxyphenyl)methane, tris(4-hydroxyphenyl)ethane, tris(4-hydroxyphenyl)- propane, tris(4-hydroxyphenyl)butane, tris(3-methyl-4-hydroxyphenyl)methane, tris(3,5- dimethyl-4-hydroxy-phenyl)methane, tetrakis(4-hydroxyphenyl)ethane, tetrakis(3,5-dimethyl-4- hydroxyphenyl)-ethane, bis(4-hydroxyphenyl)phenylphosphine oxide, dicyclopentadienyl- bis(2,6-dimethyl phenol), dicyclopentadienyl bisphenol, or the like. [0056] Arylcyclobutenes include those derived from compounds of the structure wherein B is an organic or inorganic radical of valence n (including carbonyl, sulfonyl, sulfinyl, sulfide, oxy, alkylphosphonyl, arylphosphonyl, isoalkylidene, cycloalkylidene, arylalkylidene, diarylmethylidene, methylidene dialkylsilanyl, arylalkylsilanyl, diarylsilanyl and C6-20 phenolic compounds); each occurrence of X is independently hydroxy or C _1-24 hydrocarbyl (including linear and branched alkyl and cycloalkyl); and each occurrence of Z is independently hydrogen, halogen, or C _1-12 hydrocarbyl; and n is 1 to 1000 ,or 1 to 8, or n is 2, 3, or 4. Other exemplary arylcyclobutenes and methods of arylcyclobutene synthesis can be found in US 4,743,399, US 4,540,763, US 4,642,329, US 4,661,193, US 4,724,260, and 5391,650. [0057] Perfluorovinyl ethers are typically synthesized from phenols and bromotetrafluoroethane followed by zinc catalyzed reductive elimination producing ZnFBr and the desired perfluorovinylether. By this route bis, tris, and other polyphenols can produce bis-, tris- and poly(perfluorovinylether)s. Phenols useful in their synthesis include resorcinol, catechol, hydroquinone, 2,6-dihydroxy naphthalene, 2,7-dihydroxynapthalene, 2-(diphenyl- phosphoryl)hydroquinone, bis(2,6-dimethylphenol) 2,2’-biphenol, 4,4-biphenol, 2,2’,6,6’- tetramethylbiphenol, 2,2’,3,3’,6,6’-hexamethylbiphenol, 3,3’,5,5’-tetrabromo-2,2’6,6’-tetra- methylbiphenol, 3,3’-dibromo-2,2’,6,6’-tetramethylbiphenol, 2,2’,6,6’-tetramethyl-3,3’5- dibromobiphenol, 4,4’-isopropylidenediphenol (bisphenol A), 4,4’-isopropylidenebis(2,6- dibromophenol), 4,4’-isopropylidenebis(2,6-dimethylphenol), 4,4’-isopropylidenebis(2- methylphenol), 4,4’-isopropylidenebis(2-allylphenol), 4,4’(1,3-phenylenediisopropylidene)- bisphenol, 4,4’-isopropylidenebis(3-phenylphenol) 4,4’-(1,4-phenylenediisoproylidene)- bisphenol, 4,4’-ethylidenediphenol, 4,4’oxydiphenol, 4,4’thiodiphenol, 4,4’thiobis(2,6- dimethylphenol), 4,4’-sufonyldiphenol, 4,4’-sulfonylbis(2,6-dimethylphenol) 4,4’- sulfinyldiphenol, 4,4’-hexafluoroisoproylidene)bisphenol, 4,4’(1-phenylethylidene)-bisphenol, bis(4-hydroxyphenyl)-2,2-dichloroethylene, bis(4-hydroxyphenyl)-methane, bis(2,6-dimethyl-4- hydroxyphenyl)methane, 4,4'-(cyclopentylidene)diphenol, 4,4'-(cyclohexylidene)diphenol, 4,4'- (cyclododecylidene)diphenol 4,4'-(bicyclo[2.2.1]heptylidene)-diphenol, 4,4'-(9H-fluorene-9,9- diyl)diphenol, 3,3-bis(4-hydroxyphenyl)isobenzofuran-1(3H)-one, 1-(4-hydroxyphenyl)-3,3- dimethyl-2,3-dihydro-1H-inden-5-ol, 1-(4-hydroxy-3,5-dimethylphenyl)-1,3,3,4,6-pentamethyl- 2,3-dihydro-1H-inden-5-ol, 3,3,3',3'-tetramethyl-2,2',3,3'-tetrahydro-1,1'-spirobi[inde ne]-5,6'- diol (Spirobiindane), dihydroxybenzophenone, tris(4-hydroxyphenyl)methane, tris(4- hydroxyphenyl)ethane, tris(4-hydroxyphenyl)propane, tris(4-hydroxyphenyl)butane, tris(3- methyl-4-hydroxyphenyl)methane, tris(3,5-dimethyl-4-hydroxyphenyl)methane, tetrakis(4- hydroxyphenyl)ethane, tetrakis(3,5-dimethyl-4-hydroxyphenyl)ethane, bis(4-hydroxyphenyl)- phenylphosphine oxide, dicyclopentadienylbis(2,6-dimethyl phenol), dicyclopentadienyl bis(2- methylphenol), dicyclopentadienyl bisphenol, or the like. [0058] The crosslinking agents, which also include auxiliary crosslinking agents, are not particularly limited. The crosslinking agents can be used alone or in combinations of two or more different crosslinking agents. Exemplary crosslinking agents and auxiliary crosslinking agents include oligomers or polymers with curable vinyl functionality. Such materials include oligomers and polymers having crosslinkable unsaturation. Examples include styrene butadiene rubber (SBR), butadiene rubber (BR), and nitrile butadiene rubber (NBR) having unsaturated bonding based on butadiene; natural rubber (NR), isoprene rubber (IR), chloroprene rubber (CR), butyl rubber (IIR), and halogenated butyl rubber having unsaturated bonding based on isoprene; ethylene-^-olefin copolymer elastomers having unsaturated bonding based on dicyclopentadiene (DCPD), ethylidene norbornene (ENB), or 1,4-dihexadiene (1,4-HD) (e.g., ethylene-^-olefin copolymers obtained by copolymerizing ethylene, an ^-olefin, and a diene, such as ethylene-propylene-diene terpolymer (EPDM) and ethylene-butene-diene terpolymer (EBDM)). Examples also include hydrogenated nitrile rubber, fluorocarbon rubbers such as vinylidenefluoride-hexafluoropropene copolymer and vinylidenefluoride-pentafluoropropene copolymer, epichlorohydrin homopolymer (CO), copolymer rubber (ECO) prepared from epichlorohydrin and ethylene oxide, epichlorohydrin allyl glycidyl copolymer, propylene oxide allyl glycidyl ether copolymer, propylene oxide epichlorohydrin allyl glycidyl ether terpolymer, acrylic rubber (ACM), urethane rubber (U), silicone rubber (Q), chlorosulfonated polyethylene rubber (CSM), polysulfide rubber (T) and ethylene acrylic rubber. Further examples include various liquid rubbers, for example several types of liquid butadiene rubbers, and the liquid atactic butadiene rubber that is butadiene polymer with 1,2-vinyl connection prepared by anionic living polymerization. It is also possible to use liquid styrene butadiene rubber, liquid nitrile butadiene rubber (CTBN, VTBN, ATBN, etc. by Ube Industries, Ltd.), liquid chloroprene rubber, liquid polyisoprene, dicyclopentadiene type hydrocarbon polymer, and polynorbornene (for example, as sold by Elf Atochem). [0059] Polybutadiene resins containing elevated levels of 1,2 addition are desirable for thermosetting matrices. Examples include the functionalized polybutadienes and poly(butadiene- styrene) random copolymers sold by Ricon Resins, Inc. under the trade names RICON, RICACRYL, and RICOBOND resins. These include butadienes containing both low vinyl content such as RICON 130, 131, 134, 142; polybutadienes containing high vinyl content such as RICON 150, 152, 153, 154, 156, 157, and P30D; random copolymers of styrene and butadiene including RICON 100, 181, 184, and maleic anhydride grafted polybutadienes and the alcohol condensates derived therefrom such as RICON 130MA8, RICON MA13, RICON 130MA20, RICON 131MAS, RICON 131MA10, RICON MA17, RICON MA20, RICON 184MA6 and RICON 156MA17. Also included are polybutadienes that can be used to improve adhesion including RICOBOND 1031, RICOBOND 1731, RICOBOND 2031, RICACRYL 3500, RICOBOND 1756, RICACRYL 3500; the polybutadienes RICON 104 (25% polybutadiene in heptane), RICON 257 (35% polybutadiene in styrene), and RICON 257 (35% polybutadiene in styrene); (meth)acrylic functionalized polybutadienes such as polybutadiene diacrylates and polybutadiene dimethacrylates. These materials are sold under the tradenames RICACRYL 3100, RICACRYL 3500, and RICACRYL 3801. Also are included are powder dispersions of functional polybutadiene derivatives including, for example, RICON 150D, 152D, 153D, 154D, P30D, RICOBOND 01731 HS, and RICOBOND 1756HS. Further butadiene resins include poly(butadiene-isoprene) block and random copolymers, such as those with molecular weights from 3,000 to 50,000 g/mol and polybutadiene homopolymers having molecular weights from 3,000 to 50,000 g/mol. Also included are polybutadiene, polyisoprene, and polybutadiene-isoprene copolymers functionalized with maleic anhydride functions, 2- hydroxyethylmaleic functions, or hydroxylated functionality. [0060] Further examples of oligomers and polymers with curable vinyl functionality include unsaturated polyester resins based on maleic anhydride, fumaric acid, itaconic acid and citraconic acid; unsaturated epoxy (meth)acrylate resins containing acryloyl groups, or methacryloyl group; unsaturated epoxy resins containing vinyl or allyl groups, urethane (meth)acrylate resin, polyether (meth)acrylate resin, polyalcohol (meth)acrylate resins, alkyd acrylate resin, polyester acrylate resin, spiroacetal acrylate resin, diallyl phthalate resin, diallyl tetrabromophthalate resin, diethyleneglycol bisallylcarbonate resin, and polyethylene polythiol resins. For example, the crosslinking agent. Other exemplary crosslinking agents further include polyfunctional crosslinking monomers such as (meth)acrylate monomers having two or more (meth)acrylate moieties per monomer molecule. Exemplary polyfunctional monomers include di(meth)acrylates such as 1,6-hexanediol di(meth)acrylate, 1,4-cyclohexanediol di(meth)acrylate, tripropylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, neopentyl glycol propoxylate di(meth)acrylate, neopentyl glycol ethoxylate di(meth)acrylate, neopentyl glycol propoxylate di(meth)acrylate, neopentyl glycol ethoxylate di(meth)acrylate, polyethylene glycol di(meth)acrylate, glycerol di(meth)acrylate, or the like; tri(meth)acrylates such as trimethylolpropane tri(meth)acrylate, 1,2,4- butanetriol tri(meth)acrylate, trimethylolpropane ethoxylate tri(meth)acrylate, or the like; tri(meth)allyls such as tri(meth)allyl cyanurate, tri(meth)allyl isocyanurate, tri(meth)allyl esters of citric acid, tri(meth)allyl esters of phosphoric acid, pentaerythritol tri(meth)acrylate, tris(hydroxyethyl)isocyanurate tri(meth)acrylate, or the like; tetra(meth)acrylates such as pentaerythritol tetra(meth)acrylate or the like; penta(meth)acrylates such as dipentaerythritol penta(meth)acrylate, or the like; hexa(meth)acrylates such as dipentaerythritol hexa(meth)acrylate, sorbitol hexa(meth)acrylate, or the like; glycidyl compounds such as glycidyl (meth)acrylate, (meth)allyl glycidyl ether, 1- chloro-2,3-epoxypropyl (meth)acrylate, 2-bromo-3,4-epoxybutyl (meth)acrylate, 2- (epoxyethyloxy)-ethyl (meth)acrylate, 2-(3,4-epoxybutyloxy)-ethyl (meth)acrylate, or the like; polythiol compounds such as trimethylolpropane tris(mercaptopropionate), pentaerythritol tetrakis(3-mercaptopropionate), or the like; silanes such as tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetra-n-butoxysilane, vinyltris(methylethyloximino)silane, vinyltris-(acetoxime)silane, methyltris(methylethyloximino)silane, methyltris(acetoxime)silane, vinyltrimethoxysilane, methyltrimethoxysilane, vinyltris(isopropenoxy)silane, tetraacetoxy- silane, methyltriacetoxysilane, ethyltriacetoxysilane, vinyltriacetoxysilane, di-t-butoxy- diacetoxysilane, methyltris(ethyl lactate)silane, vinyltris(ethyl lactate)silane, or the like; carbodiimides such as N-(3-dimethylaminopropyl)-N^-ethylcarbodiimide hydrochloride, dicyclohexylcarbodiimide, or the like; or a combination thereof. The curable thermosetting composition can optionally include a crosslinking catalyst, such as a carboxylic acid salt. [0061] When the curable thermosetting composition includes a crosslinking agent, the crosslinking agent can be included in an amount of 1 to 60 wt%, or 5 to 45 wt%, or 10 to 30 wt%, based on total weight of the curable thermosetting composition. [0062] The curable thermosetting composition can include one or more curing agents. As used herein, the term “curing agent” includes compounds that are variously described as curing agents, hardeners, or the like, or as both. [0063] Exemplary curing agents and hardeners include amines, alcohols, phenols, carboxylic acids, acid anhydrides, and the like. For example, phenolic hardeners include novolac type phenol resins, resole type phenol resins, cresol novolac resins, aralkyl type phenol resins, phenol aralkyl resins, cresol aralkyl resins, naphthol aralkyl resins, dicyclopentadiene type phenol resins, terpene modified phenol resins, biphenyl type phenol resins, biphenyl-modified phenol aralkyl resins, bisphenols, triphenylmethane type phenol resins, tetraphenylol ethane resins, naphthol novolac resins, naphthol-phenol co-condensed novolac resins, naphthol-cresol co-condensed novolac resins, amino triazine modified phenol resins, or a combination thereof. Examples of the anhydride hardeners include methylhexahydrophthalic anhydride (MHHPA), methyltetrahydrophthalic anhydride, styrene-maleic anhydride copolymers (SMA), and olefin- maleic anhydride copolymers such as maleic anhydride grafted polyethylene, maleic anhydride grafted polypropylene, or a combination thereof. Other curing agents and hardeners include compounds such as dicyandiamides, polyamides, amidoamines, phenalkamines, Mannich bases, anhydrides, phenol-formaldehyde resins, amine-formaldehyde resins, phenol-formaldehyde resins, carboxylic acid functional polyesters, polysulfides, polymercaptans, isocyanates, cyanate ester compounds, or any combination thereof. Other exemplary curing agents include tertiary amines, Lewis acids, and oligomers or polymers with unsaturation. [0064] When the curable thermosetting composition includes a curing agent, the curing agent can be included in an amount of 0.01 to 50 wt%, or 0.1 to 30 wt%, or 0.1 to 20 wt%, based on total weight of the curable thermosetting composition. [0065] The curable thermosetting composition can include a curing catalyst. As used herein, the term “curing catalyst” includes compounds that are variously described as curing accelerators, curing promoters, curing catalysts, and curing co-catalysts. [0066] Exemplary curing accelerators include heterocyclic accelerators such as a substituted or unsubstituted C3-6 heterocycle comprising 1 to 4 ring heteroatoms, wherein each heteroatom is independently the same or different, and is nitrogen, oxygen, phosphorus, silicon, or sulfur. Heterocyclic accelerators include benzotriazoles; triazines; piperazines such as aminoethylpiperazine, N-(3-aminopropyl)piperazine, or the like; imidazoles such as 1- methylimidazole, 2-methylimidazole, 3-methyl imidazole, 4-methylimidazole, 5- methylimidazole, 1-ethylimidazole, 2-ethylimidazole, 3-ethylimidazole, 4-ethylimidazole, 5- ethylimidazole, 1-n-propylimidazole, 2-n-propylimidazole, 1-isopropylimidazole, 2- isopropylimidazole, 1-n-butylimidazole, 2-n-butylimidazole, 1-isobutylimidazole, 2- isobutylimidazole, 2-undecyl-1H-imidazole, 2-heptadecyl-1H-imidazole, 1,2- dimethylimidazole, 1,3-dimethylimidazole, 2,4-dimethylimidazole, 2-ethyl-4-methylimidazole, 1-phenylimidazole, 2-phenyl-1H-imidazole, 4-methyl-2-phenyl-1H-imidazole, 2-phenyl-4- methylimidazole, 1-benzyl-2-methylimidazole, 1-benzyl-2-phenylimidazole, 1-cyanoethyl-2- methylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 1-cyanoethyl-2-undecylimidazole, 1- cyanoethyl-2-phenylimidazole, 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5- hydroxymethylimidazole, 1-cyanoethyl-2-phenyl-4,5-di(2-cyanoethoxy)methylimidazole; cyclic amidine such as 4-diazabicyclo(2,2,2)octane, diazabicycloundecene, 2-phenyl imidazoline, or the like; N,N-dimethylaminopyridine; a sulfamidate; or a combination thereof. [0067] Amine curing accelerators include isophoronediamine, triethylenetetraamine, diethylenetriamine, 1,2- and 1,3-diaminopropane, 2,2-dimethylpropylenediamine, 1,4-diaminobutane, 1,6-diaminohexane, 1,7-diaminoheptane, 1,8-diaminooctane, 1,9-diaminononane, 1,12-diaminododecane, 4-azaheptamethylenediamine, N,N’-bis(3-aminopropyl)butane-1,4-diamine, dicyanamide, diamide diphenylmethane, diamide diphenylsulfonic acid (amine adduct), 4,4’-methylenedianiline, diethyltoluenediamine, m-phenylenediamine, p-phenylenediamine, melamine formaldehyde resins, urea formaldehyde resins, tetraethylenepentamine, 3-diethylaminopropylamine, 3,3’-iminobispropylamine, 2,4- bis(p-aminobenzyl)aniline, tetraethylenepentamine, 3-diethylaminopropylamine, 2,2,4- and 2,4,4-trimethylhexamethylenediamine, 1,2- and 1,3-diaminocyclohexane, 1,4-diamino-3,6- diethylcyclohexane, 1,2-diamino-4-ethylcyclohexane, 1,4-diamino-3,6-diethylcyclohexane, 1-cyclohexyl-3,4-diminocyclohexane, 4,4’-diaminondicyclohexylmethane, 4,4’-diaminodicyclohexylpropane, 2,2-bis(4-aminocyclohexyl)propane, 3,3’-dimethyl-4,4’- diaminodicyclohexylmethane, 3-amino-1-cyclohexaneaminopropane, 1,3- and 1,4- bis(aminomethyl)cyclohexane, m- and p-xylylenediamine, or diethyl toluene diamines; or a tertiary amine hardening accelerator such as triethylamine, tributylamine, dimethylaniline, diethylaniline, benzyldimethylamine (BDMA), ^-methylbenzyldimethylamine, N,N-dimethyl amino pyridine, N,N-dimethylaminoethanol, N,N-dimethylaminocresol, or tri(N,N- dimethylaminomethyl)phenol; or a combination thereof. [0068] The curing accelerator can be a latent cationic cure catalyst including, for example, diaryliodonium salts, phosphonic acid esters, sulfonic acid esters, carboxylic acid esters, phosphonic ylides, triarylsulfonium salts, benzylsulfonium salts, aryldiazonium salts, benzylpyridinium salts, benzylammonium salts, isoxazolium salts, or the like, or a combination thereof. The diaryliodonium salt can have the structure [(R ¹⁰ )(R ¹¹ )I] ⁺ X- , wherein R ¹⁰ and R ¹¹ are each independently a C _6-14 monovalent aromatic hydrocarbon radical, optionally substituted with from 1 to 4 monovalent radicals selected from C1-20 alkyl, C1-20 alkoxy, nitro, and chloro; and wherein X- is an anion. The additional cure accelerator can have the structure [(R ¹⁰ )(R ¹¹ )I] ⁺ SbF6- , wherein R ¹⁰ and R ¹¹ are each independently a C6-14 monovalent aromatic hydrocarbon, optionally substituted with from 1 to 4 C _1-20 alkyl, C _1-20 alkoxy, nitro, or chloro; for example, 4- octyloxyphenyl phenyl iodonium hexafluoroantimonate. [0069] The curing accelerator can be a metal salt complex, such as a copper (II) aluminum (III), zinc, cobalt, tin salt of an aliphatic or aromatic carboxylic acid selected from copper (II), tin (II), and aluminum (III) salts of acetate, stearate, gluconate, citrate, benzoate, and mixtures thereof. For example, the cure accelerator can be a copper (II) or aluminum (III) salts of ^-diketonates; copper (II), iron (II), iron (III), cobalt (II), cobalt (III), or aluminum (III) salts of acetylacetonates; zinc (II), chromium (II), or manganese (II) salts of octoates; or a combination thereof. [0070] When the curable thermosetting composition includes a curing catalyst, the curing catalyst can be included in an amount of 0.01 to 5 wt%, or 0.05 to 5 wt%, or 0.1 to 5 wt%, based on total weight of the curable thermosetting composition. [0071] The curable thermosetting composition can optionally include a curing initiator, such as a peroxide compound. Exemplary peroxide curing initiators can include benzoyl peroxide, dicumyl peroxide, methyl ethyl ketone peroxide, lauryl peroxide, cyclohexanone peroxide, t-butyl hydroperoxide, t-butyl benzene hydroperoxide, t-butyl peroctoate, t- butylperoxybenzoate, t-butylperoxy 2-ethylhexyl carbonate, 2,4-dichlorobenzoyl peroxide, 2,5- dimethylhexane-2,5-dihydroperoxide, butyl-4,4-bis(tert-butyldioxy)valerate, 2,5-dimethyl-2,5- di(t-butylperoxy)-hex-3-yne, di-t-butylperoxide, t-butylcumyl peroxide, ^,^^-bis(t-butylperoxy- m-isopropyl)benzene, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, dicumylperoxide, di(t- butylperoxy isophthalate, t-butylperoxybenzoate, 2,2-bis(t-butylperoxy)butane, 2,2-bis(t- butylperoxy)octane, 2,5-dimethyl-2,5-di(benzoylperoxy)hexane, 1,1-di-(tert-butylperoxy)-3,3,5- trimethylcyclohexane, di(trimethylsilyl)peroxide, trimethylsilylphenyltriphenylsilyl peroxide, or the like, or a combination thereof. [0072] When the curable thermosetting composition includes a curing initiator, the curing initiator can be included in an amount of 0.1 to 5 wt%, or 0.5 to 5 wt%, or 1 to 5 wt%, based on total weight of the curable thermosetting composition. [0073] Flame retardants include, for example, organic compounds that comprise phosphorus, bromine, or chlorine. Non-brominated and non-chlorinated phosphorus-containing flame retardants can be preferred in certain applications for regulatory reasons, for example organic phosphates and organic compounds containing phosphorus-nitrogen bonds. [0074] Examples of phosphorous flame retardants include phosphates, phosphazenes, phosphite esters, phosphines, phosphinates, polyphosphates, and phosphonium salts. Phosphates include triphenyl phosphate, tricresyl phosphate, isopropylated triphenyl phosphate, phenyl bis(dodecyl) phosphate, phenyl bis(neopentyl) phosphate, phenyl bis(3,5,5'-trimethylhexyl) phosphate, ethyl diphenyl phosphate, 2-ethylhexyl di(p-tolyl) phosphate, bis(2-ethylhexyl) p- tolyl phosphate, tritolyl phosphate, bis(2-ethylhexyl) phenyl phosphate, tri(nonylphenyl) phosphate, bis(dodecyl) p-tolyl phosphate, dibutyl phenyl phosphate, 2-chloroethyl diphenyl phosphate, p-tolyl bis(2,5,5'-trimethylhexyl) phosphate, 2-ethylhexyl diphenyl phosphate, xylenyl-diphenyl phosphate; cresyl-diphenyl phosphate; 1,3-phenylenebis(di-2,6-xylenyl phosphate); 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO), tetraphenyl diphosphate (RDP), condensed phosphate compounds such as aromatic condensed phosphate compounds; and cyclic phosphate compounds, bis(diphenyl) phosphate of hydroquinone, bis(diphenyl) phosphate of bisphenol A, or the like, or their oligomeric or polymeric counterparts, or a combination thereof. [0075] Examples of the phosphazene compounds include cyclic and chain phosphazene compounds. The cyclic phosphazene compounds (cyclophosphazenes) have a cyclic structure in which phosphorus-nitrogen double bonds are present in the molecule. Examples of phosphinate compounds include aluminum dialkylphosphinate, aluminum tris-(diethylphosphinate), aluminum tris-(methylethylphosphinate), aluminum tris-(diphenylphosphinate), zinc bis- (diethylphosphinate), zinc bis-(methylphosphinate), zinc bis-(diphenylphosphinate), titanyl bis- (diethylphosphinate), titanyl bis-(methylethylphosphinate), and titanyl bis- (diphenylphosphinate). Examples of polyphosphate compounds include melamine polyphosphate, melam polyphosphate, and melem polyphosphate. Examples of phosphonium salt compounds include tetraphenylphosphonium tetraphenylborate. Examples of the phosphite ester compounds include trimethylphosphite and triethylphosphite. Flame retardant compounds containing phosphorus-nitrogen bonds include phosphonitrilic chloride, phosphorus ester amides, phosphoric acid amides, phosphonic acid amides, phosphinic acid amides, and tris(aziridinyl) phosphine oxide. [0076] Halogenated materials can also be used as flame retardants, for example bisphenols such as 2,2-bis-(3,5-dichlorophenyl)-propane; bis-(2-chlorophenyl)-methane; bis(2,6- dibromophenyl)-methane; 1,1-bis-(4-iodophenyl)-ethane; 1,2-bis-(2,6-dichlorophenyl)-ethane; 1,1-bis-(2-chloro-4-iodophenyl)ethane; 1,1-bis-(2-chloro-4-methylphenyl)-ethane; 1,1-bis-(3,5- dichlorophenyl)-ethane; 2,2-bis-(3-phenyl-4-bromophenyl)-ethane; 2,6-bis-(4,6- dichloronaphthyl)-propane; and 2,2-bis-(3,5-dichloro-4-hydroxyphenyl)-propane 2,2 bis-(3- bromo-4-hydroxyphenyl)-propane. Other halogenated materials include 1,3-dichlorobenzene, 1,4-dibromobenzene, 1,3-dichloro-4-hydroxybenzene, and biphenyls such as 2,2'- dichlorobiphenyl, polybrominated 1,4-diphenoxybenzene, 2,4'-dibromobiphenyl, and 2,4'- dichlorobiphenyl as well as decabromobiphenyl ether, decabromodiphenylethane, as well as oligomeric and polymeric halogenated aromatic compounds, such as brominated styrene, 4,4- dibromobiphenyl, ethylene-bis(tetrabromophthalimide), or a copolycarbonate of bisphenol A and tetrabromobisphenol A and a carbonate precursor, e.g., phosgene. Metal synergists, e.g., antimony oxide, can also be used with the flame retardant. [0077] Inorganic flame retardants can also be used, for example salts of C1-16 alkyl sulfonate salts such as potassium perfluorobutane sulfonate (Rimar salt), potassium perfluoroctane sulfonate, tetraethylammonium perfluorohexane sulfonate, and potassium diphenylsulfone sulfonate; salts such as Na ₂ CO ₃ , K ₂ CO ₃ , MgCO ₃ , CaCO ₃ , and BaCO ₃ , or fluoro-anion complexes such as Li3AlF6, BaSiF6, KBF4, K3AlF6, KAlF4, K2SiF6, or Na3AlF6. [0078] When the curable thermosetting composition includes a flame retardant, the flame retardant can be included in an amount of greater than 1 wt%, or 1 to 20 wt%, or 5 to 20 wt%, based on total weight of the curable thermosetting composition. [0079] The curable thermosetting composition can further include inorganic or organic fillers, such as a particulate filler, a fibrous filler, or the like, or a combination thereof. Any inorganic and organic fillers, including those known in the art, can be used without limitation. [0080] Exemplary fillers include, for example, clay, talc, kaolin, wollastonite, mica, calcium carbonate, magnesium carbonate; alumina, thiourea, glass powder, B- or Sn-based fillers such as zinc borate, zinc stannate and zinc hydroxystannate; metal oxides such as zinc oxide and tin oxide. alumina, silica (including fused silica, fumed silica, spherical silica, and crystalline silica), boron nitride (including spherical boron nitride), aluminum nitride, silicon nitride, magnesia, magnesium silicate, antimony trioxide, glass fibers (chopped, milled, or cloth), glass mat, glass bubbles, hollow glass microspheres, aramid fibers, quartz, or the like, or a combination thereof. Other exemplary inorganic fillers include powdered titanium ceramics such as any one of the titanates of barium. lead, strontium, calcium, bismuth, magnesium, or the like. Inorganic fillers also include hydrates such as aluminum hydroxide, magnesium hydroxide, zeolite, and hydrotalcite. In an aspect, the filler can be treated with a coupling agent as disclosed herein. [0081] Glass fibers include those based on E, A, C, ECR, R, S, D, and NE glasses, as well as quartz. The glass fiber can have any suitable diameter, such as from 2 to 30 micrometers (^m), or 5 to 25 ^m, or 5 to 15 ^m. The length of the glass fibers before compounding are not limited and can be 2 to 7 millimeters (mm), or 1.5 to 5 mm. Alternatively, longer glass fibers or continuous glass fibers can be used. Suitable glass fiber is commercially available from suppliers such as Owens Corning, Nippon Electric Glass, PPG, and Johns Manville. [0082] The organic filler can be, for example, polytetrafluoroethylene powder, polyphenylene sulfide powder, and poly(ether sulfone) powder, poly(phenylene ether) powder, polystyrene, divinylbenzene resin, or the like, or a combination thereof. [0083] The filler can be selected based on the thermal expansion coefficient (CTE) and thermal conductivity requirements. For example, Al ₂ O ₃ , BN, AlN, or a combination thereof, can be used for an electronics module with high thermal conductivity. For example, MgO can be used for increased thermal conductivity and increased CTE. For example, SiO ₂ (e.g., amorphous SiO2) can be used for a lightweight module having a low CTE and a small dielectric constant. [0084] When the curable thermosetting composition includes a filler, the filler can be included in an amount of greater than 1 wt%, or 1 to 50 wt%, or 1 to 30 wt%, or 10 to 30 wt%, based on total weight of the curable thermosetting composition. [0085] Coupling agents, also referred to as adhesion promoters, include chromium complexes, silanes, titanates, zircon-aluminates, olefin-maleic anhydride copolymers, reactive cellulose esters, and the like. Exemplary olefin-maleic anhydride copolymers can include maleic anhydride grafted polyethylene, maleic anhydride grafted polypropylene, or a combination thereof. Exemplary silanes can include epoxysilane compound, aminosilane compounds methacryloxysilane compounds, vinylsilane compounds, or a combination thereof. [0086] Examples of aminosilane coupling agents are ^ -aminopropyltrimethoxy-silane, ^-aminopropyltriethoxysilane, N-beta(aminoethyl) ^-aminopropylmethyl-dimethoxysilane, N- beta(aminoethyl) ^ -aminopropyltrimethoxysilane, and N-beta(aminoethyl)^- aminopropyltriethoxysilane. Illustrative epoxysilane coupling agents include ^ - glycidoxypropylmethyldiethoxysilane, gamma-glycidoxypropyltrimethoxysilane, and ^- glycidoxypropyltriethoxysilane. Examples of methacryloxysilane coupling agents include ^- methacryloxypropylmethyldimethoxysilane, ^ -methacryloxypropyl-trimethoxysilane, ^- methacryloxypropyldiethoxysilane, and ^-methacryloxypropyltriethoxysilane. [0087] Other exemplary silane coupling agents include bis(3-triethoxysilylpropyl) tetrasulfide, bis(3-triethoxysilylpropyl) trisulfide, bis(3-triethoxysilylpropyl) disulfide, bis(2- triethoxysilylethyl) tetrasulfide, bis(3-trimethoxysilylpropyl) tetrasulfide, bis(2- trimethoxysilylethyl) tetrasulfide, 3-mercaptopropyltrimethoxysilane, 3- mercaptopropyltriethoxysilane, 2-mercaptoethyltrimethoxysilane, 2-mercaptoethyltri- ethoxysilane, 3-trimethoxysilylpropyl-N,N-dimethylthiocarbamoyl tetrasulfide, 3- triethoxysilylpropyl-N,N-dimethylthiocarbamoyl tetrasulfide, 2-triethoxysilylethyl-N,N- dimethylthiocarbamoyl tetrasulfide, 3-trimethoxysilylpropylbenzothiazolyl tetrasulfide, 3- triethoxysilylpropylbenzolyl tetrasulfide, 3-triethoxysilylpropyl methacrylate monosulfide, 3- trimethoxysilylpropyl methacrylate monosulfide, bis(3-diethoxymethylsilylpropyl) tetrasulfide, 3-mercaptopropyldimethoxymethylsilane, dimethoxymethylsilylpropyl-N,N-dimethylthio- carbamoyl tetrasulfide, dimethoxymethylsilylpropylbenzothiazolyl tetrasulfide, or the like, or a combination thereof. The silane coupling agent can be a polysulfide silane coupling agent having 2 to 4 sulfur atoms forming a polysulfide bridge. For example, the coupling agent can be a bis(3-triethoxysilylpropyl) di-, tri-, or tetrasulfide. [0088] When the curable thermosetting composition includes a coupling agent, the coupling agent can be included in an amount of 0.01 to 5 wt%, or 0.05 to 5 wt%, or 0.1 to 5 wt%, based on total weight of the curable thermosetting composition. [0089] The curable thermosetting composition can optionally include a solvent. The solvent can be, for example, a C _3-8 ketone, a C _3-8 N,N-dialkylamide, a C _4-16 dialkyl ether, a C _6-12 aromatic hydrocarbon, a C1-3 chlorinated hydrocarbon, a C3-6 alkyl alkanoate, a C2-6 alkyl cyanide, or a combination thereof. Specific ketone solvents include, for example, acetone, methyl ethyl ketone, methyl isobutyl ketone, or a combination thereof. Specific C4-8 N,N- dialkylamide solvents include, for example, dimethylformamide, dimethylacetamide, N-methyl- 2-pyrrolidone, or a combination thereof. Specific dialkyl ether solvents include, for example, tetrahydrofuran, ethylene glycol monomethylether, dioxane, or a combination thereof. Specific aromatic hydrocarbon solvents include, for example, benzene, toluene, xylenes, styrene, divinylbenzenes, or a combination thereof. The aromatic hydrocarbon solvent can be non- halogenated. Specific C3-6 alkyl alkanoates include, for example, methyl acetate, ethyl acetate, methyl propionate, ethyl propionate, or a combination thereof. Specific C _2-6 alkyl cyanides include, for example, acetonitrile, propionitrile, butyronitrile, or a combination thereof. Specific C _2-6 alkyl cyanides include, for example, acetonitrile, propionitrile, butyronitrile, or a combination thereof. For example, the solvent can be N,N-dimethylformamide, N,N- dimethylacetamide, N,N-diethylacetamide, N,N-dimethylmethoxyacetamide, N-methyl-2- pyrrolidone, N-cyclohexylpyrrolidinone, N-methylcaprolactam, 1,3-dimethyl-2-imidazolidone, 1,2-dimethoxyethane, 1,3-dioxane, 1,4-dioxane, tetrahydrofuran, ^-butyrolactone, ^- caprolactone, dimethylsulfoxide, benzophenone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, diglyme, triglyme, tetraglyme, N,N-dimethylethyleneurea, N,N- dimethylpropyleneurea, tetramethylurea, propylene glycol phenyl ether, anisole, veratrole, o- dichlorobenzene, chlorobenzene, trichloroethane, methylene chloride, chloroform, pyridine, picoline, ethyl lactate, n-butyl acetate, butyl cellosolve acetate, butyl carbitol acetate, ethyl cellosolve acetate, ethyl carbitol acetate, propylene carbonate, sulfolane, an ionic liquid, or a combination thereof. [0090] When a solvent is utilized, the curable thermosetting composition can include 2 to 99 wt% of the solvent, based on weight total of the curable thermosetting composition. For example, the solvent amount can be 5 to 80 wt%, or 10 to 60 wt%, or 20 to 50 wt%, based on weight total of the curable thermosetting composition. The solvent can be chosen, in part, to adjust the viscosity of the curable thermosetting composition. Thus, the solvent amount can depend on variables including the type and the linear block copolymer, the type and amount of other components such as curing additive, the type and amount of any auxiliary thermosetting resin(s), and the processing temperature used for any subsequent processing of the curable thermosetting composition, for example, impregnation of a reinforcing structure with the curable thermosetting composition for the preparation of a composite. The solvent can be anhydrous. For example, the solvent can include less than 100 parts per million (ppm), or less than 50 ppm, or less than 10 ppm of water based on total weight of the solvent. [0091] The curable thermosetting composition can further include a curable unsaturated monomer composition, which can include, for example, a monofunctional styrenic compound (e.g., styrene), a monofunctional (meth)acrylic compound, or the like, or a combination thereof. For example, the curable unsaturated monomer composition can be an alkene-containing monomer or an alkyne-containing monomer. Exemplary alkene- and alkyne-containing monomers includes those described in U.S. Patent No.6,627,704 to Yeager et al., and include (meth)acrylates, (meth)acrylamides, N-vinylpyrrolidone, and vinylazalactones as disclosed in U.S. Pat. No.4,304,705 of Heilman et al. Exemplary monofunctional monomers include mono(meth)acrylates, such as methyl (meth)acrylate, ethyl (meth)acrylate, isopropyl (meth)acrylate, isooctyl (meth)acrylate, isobornyl (meth)acrylate, (meth)acrylic acid, n-hexyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, N-vinylcaprolactam, N-vinylpyrrolidone, (meth)acrylonitrile, or the like, or a combination thereof. [0092] The curable thermosetting composition can, optionally, further include one or more additional additives. Additional additives include, for example, dyes, pigments, colorants, antioxidants, heat stabilizers, light stabilizers, plasticizers, defoaming agents, lubricants, dispersants, flow modifiers, drip retardants, antiblocking agents, antistatic agents, flow-promoting agents, processing aids, substrate adhesion agents, mold release agents, toughening agents, low-profile additives, stress-relief additives, or the like, or a combination thereof. When present, the additional additives can be included in any effective amount, for example in an amount of 0.01 to 20 wt%, or 0.01 to 10 wt%, or 0.01 to 5 wt%, or 0.01 to 1 wt%, based on the total weight of the curable thermosetting composition. [0093] The curable thermosetting composition can be prepared by combining the capped poly(phenylene ether) and the other optional components disclosed herein using any suitable method. [0094] Also provided is a cured thermoset composition comprising a cured product of the curable thermosetting composition. There is no particular limitation on the method by which the curable thermosetting composition can be cured. The curable composition can, for example, be cured thermally or by using irradiation techniques, including UV irradiation or electron beam irradiation. For example, a cured product can be obtained by heating the curable thermosetting composition defined herein for a time and temperature sufficient to evaporate the solvent and effect curing. When heat curing is used, the temperature can be 30 to 400°C, or 50 to 250°C, or 100 to 250°C. The heating can be for 1 minute to 24 hours, or 1 minute to 6 hours, or 3 hours to 5 hours. The curing can be staged to produce a partially cured and often tack-free resin, which then is fully cured by heating for longer periods or temperatures within the aforementioned ranges. As used herein, the term “cured” encompasses products that are partially cured or fully cured. [0095] The cured thermoset composition can have one or more desirable properties. For example, the thermoset composition can have a glass transition temperature of greater than or equal to 165°C, preferably greater than or equal to 170°C, more preferably 165 to 180°C. The thermoset composition can also advantageously exhibit a low dielectric constant (Dk), a low dissipation factor (Df), and reduced moisture absorption. For example, the thermoset composition can have a dielectric constant of less than 3.0, preferably less than 2.75, more preferably less than 2.6 at a frequency of 10 GHz. The thermoset composition can have a dissipation factor of less than 0.01, or less than 0.005 at a frequency of 10 GHz. Thus, thermoset compositions comprising the linear block copolymer of the present disclosure can be particularly well suited for use in electronics applications. [0096] The curable thermosetting compositions and cured thermoset compositions can be used in a variety of applications and uses, including any applications where conventional thermosetting compositions are used. For example, useful articles including the curable thermosetting composition or the cured thermoset composition can be in the form of a composite, a foam, a fiber, a layer, a coating, an encapsulant, an adhesive, a sealant, a molded component, a prepreg, a casing, a laminate, a metal clad laminate, an electronic composite, a structural composite, or a combination thereof. Exemplary uses and applications include coatings such as protective coatings, sealants, weather resistant coatings, scratch resistant coatings, and electrical insulative coatings; adhesives; binders; glues; composite materials such as those using carbon fiber and fiberglass reinforcements. When utilized as a coating, the disclosed compounds and compositions can be deposited on a surface of a variety of underlying substrates. For example, the compositions can be deposited on a surface of metals, plastics, glass, fiber sizings, ceramics, stone, wood, or any combination thereof. The disclosed compositions can be used as a coating on a surface of a metal container (e.g., aluminum or steel), such as those commonly used for packaging and containment in the paint and surface covering industries. The curable thermosetting composition and the cured thermoset composition derived therefrom can also be particularly well suited for use in forming electrical components and computer components. [0097] Methods of forming a composite can include impregnating a reinforcing structure with a curable thermosetting composition; partially curing the curable thermosetting composition to form a prepreg; and laminating a plurality of prepregs. The reinforcing structure can be a porous base material such as a fibrous preform or substrate, or other porous material comprising a ceramic, a polymer, a glass, carbon, or a combination thereof. For example, the porous base material can be woven or non-woven glass fabric, a fiberglass fabric, or carbon fiber. When the article includes a fibrous preform, the method of manufacturing the article can include forming the article from the curable thermosetting composition by coating or impregnating the preform with the curable composition. The impregnated fibrous preform can optionally be shaped before or after removing the solvent. In some aspects, the curable thermosetting composition layer can further comprise a woven or nonwoven glass fabric. For example, the curable layer can be prepared by impregnating the glass fabric with a curable composition and removing the solvent from the impregnated glass fabric. Exemplary reinforcing structures are described, for example, in Anonymous (Hexcel Corporation), “Prepreg Technology”, March 2005, Publication No. FGU 017b; Anonymous (Hexcel Corporation), “Advanced Fibre Reinforced Matrix Products for Direct Processes”, June 2005, Publication No. ITA 272; and Bob Griffiths, “Farnborough Airshow Report 2006”, CompositesWorld.com, September 2006. The weight and thickness of the reinforcing structure are chosen according to the intended use of the composite using criteria well known to those skilled in the production of fiber reinforced resin composites. The reinforced structure can contain various finishes suitable for the thermosetting components of the curable thermosetting composition. [0098] The method of manufacturing the articles from the curable thermosetting composition can include partially curing the curable thermosetting composition to form a prepreg, or fully curing the curable thermosetting composition to form a composite article. References herein to properties of the “cured composition” refer to a composition that is substantially fully cured. For example, the resin in a laminate formed from prepregs is typically substantially fully cured. One skilled in the thermoset arts can determine whether a sample is partially cured or substantially fully cured without undue experimentation. The curing can be before or after removing the solvent from the curable composition. In addition, the article can be further shaped before removal of the solvent or after removal of the solvent, before curing, after partial curing, or after full curing, for example by thermoforming. In an aspect, the article is formed, and the solvent is removed; the article is partially cured (B-staged); optionally shaped; and then further cured. [0099] Commercial-scale methods of forming composites are known in the art, and the curable thermosetting compositions described herein are readily adaptable to existing processes and equipment. For example, prepregs are often produced on treaters. The main components of a treater include feeder rollers, a resin impregnation tank, a treater oven, and receiver rollers. The reinforcing structure (E-glass, for example) is usually rolled into a large spool. The spool is then put on the feeder rollers that turn and slowly roll out the reinforcing structure. The reinforcing structure then moves through the resin impregnation tank, which contains the curable thermosetting composition. The curable composition impregnates the reinforcing structure. After emerging from the tank, the coated reinforcing structure moves upward through the vertical treater oven, which is typically at a temperature of 175 to 200°C, and the solvent is evaporated. The resin begins to polymerize at this time. When the composite comes out of the tower it is sufficiently cured so that the web is not wet or tacky. The cure process, however, is stopped short of completion so that additional curing can occur when laminate is made. The web then rolls the prepreg onto a receiver roll. [0100] The curable thermosetting composition can be used as a coating, for example in the preparation of a multilayer article. A method of manufacturing the coating can include combining the curable thermosetting composition and optionally a fluoropolymer and forming a coating on a substrate. For example, a multilayer article can be manufactured by forming a layer including the curable thermosetting composition, removing the solvent from the layer and optionally curing to provide a primer layer, forming a second layer comprising a ceramic (e.g., Al ₂ O ₃ , TiO ₂ , ZrO ₂ , Cr ₂ O ₃ , SiO ₂ , MgO, BeO, Y ₂ O ₃ , Al ₂ O ₃ -SiO ₂ , MgO-ZrO ₂ , SiC, WC, B ₄ C, TiC, Si3N4, TiN, BN, AlN, TiB, ZrB2, or the like), a thermoplastic polymer, a fluoropolymer (e.g., polytetrafluoroethylene, tetrafluoroethylene-perfluoroalkylvinylether copolymers, tetrafluoroethylene-hexafluoropropylene copolymers, polychlorotrifluoroethylene, tetrafluoroethylene-ethylene copolymers, polyvinylidene fluoride, or the like), or a combination thereof on the primer layer to provide the multilayer article, and optionally thermally treating the multilayer article to cure the curable thermosetting composition. In some aspects, the second layer can further include the curable thermosetting composition. [0101] Additional applications for the curable thermosetting compositions include, for example, acid bath containers; neutralization tanks; aircraft components; bridge beams; bridge deckings; electrolytic cells; exhaust stacks; scrubbers; sporting equipment; stair cases; walkways; automobile exterior panels such as hoods and trunk lids; floor pans; air scoops; pipes and ducts, including heater ducts; industrial fans, fan housings, and blowers; industrial mixers; boat hulls and decks; marine terminal fenders; tiles and coatings; building panels; business machine housings; trays, including cable trays; concrete modifiers; dishwasher and refrigerator parts; electrical encapsulants; electrical panels; tanks, including electrorefining tanks, water softener tanks, fuel tanks, and various filament-wound tanks and tank linings; furniture; garage doors; gratings; protective body gear; luggage; outdoor motor vehicles; pressure tanks; optical waveguides; radomes; railings; railroad parts such as tank cars; hopper car covers; car doors; truck bed liners; satellite dishes; signs; solar energy panels; telephone switchgear housings; tractor parts; transformer covers; truck parts such as fenders, hoods, bodies, cabs, and beds; insulation for rotating machines including ground insulation, turn insulation, and phase separation insulation; commutators; core insulation and cords and lacing tape; drive shaft couplings; propeller blades; missile components; rocket motor cases; wing sections; sucker rods; fuselage sections; wing skins and flarings; engine narcelles; cargo doors; tennis racquets; golf club shafts; fishing rods; skis and ski poles; bicycle parts; transverse leaf springs; pumps, such as automotive smog pumps; electrical components, embedding, and tooling, such as electrical cable joints; wire windings and densely packed multi-element assemblies; sealing of electromechanical devices; battery cases; resistors; fuses and thermal cut-off devices; coatings for printed wiring boards; casting items such as capacitors, transformers, crankcase heaters; small molded electronic parts including coils, capacitors, resistors, and semiconductors; as a replacement for steel in chemical processing, pulp and paper, power generation, and wastewater treatment; scrubbing towers; pultruded parts for structural applications, including structural members, gratings, and safety rails; swimming pools, swimming pool slides, hot-tubs, and saunas; drive shafts for under the hood applications; dry toner resins for copying machines; marine tooling and composites; heat shields; submarine hulls; prototype generation; development of experimental models; laminated trim; drilling fixtures; bonding jigs; inspection fixtures; industrial metal forming dies; aircraft stretch block and hammer forms; vacuum molding tools; flooring, including flooring for production and assembly areas, clean rooms, machine shops, control rooms, laboratories, parking garages, freezers, coolers, and outdoor loading docks; electrically conductive compositions for antistatic applications; for decorative flooring; expansion joints for bridges; injectable mortars for patch and repair of cracks in structural concrete; grouting for tile; machinery rails; metal dowels; bolts and posts; repair of oil and fuel storage tanks, and numerous other applications. [0102] Processes useful for preparing the articles and materials include those generally known to the art for the processing of thermosetting resins. Such processes have been described in the literature as in, for example, Engineered Materials Handbook, Volume 1, Composites, ASM International Metals Park, Ohio, copyright 1987 Cyril A. Dostal Senior Ed, pp.105-168 and 497-533, and “Polyesters and Their Applications” by Bjorksten Research Laboratories, Johan Bjorksten (pres.) Henry Tovey (Ch. Lit. Ass.), Betty Harker (Ad. Ass.), James Henning (Ad. Ass.), Reinhold Publishing Corporation, New York, 1956. Processing techniques include resin transfer molding; sheet molding; bulk molding; pultrusion; injection molding, including reaction injection molding (RIM); atmospheric pressure molding (APM); casting, including centrifugal and static casting open mold casting; lamination including wet or dry lay up and spray lay up; also included are contact molding, including cylindrical contact molding; compression molding; including vacuum assisted resin transfer molding and chemically assisted resin transfer molding; matched tool molding; autoclave curing; thermal curing in air; vacuum bagging; pultrusion; Seeman's Composite Resin Infusion Manufacturing Processing (SCRIMP); open molding, continuous combination of resin and glass; and filament winding, including cylindrical filament winding. For example, an article can be prepared by a resin transfer molding process. [0103] Also provided is an article derived from the curable thermosetting composition, wherein the article is a composite, a foam, a fiber, a layer, a coating, an encapsulant, an adhesive, a sealant, a molded component, a prepreg, a casing, a cast article, a laminate, or a combination thereof; or wherein the article is a metal clad laminate, an electronic composite, a structural composite, or a combination thereof. Articles can be manufactured as disclosed herein, for example by casting, molding, extruding, or the like, and removing the solvent from the formed article. In an aspect, the article can be a layer, and can be formed by casting the curable composition onto a substrate to form a cast layer. The solvent can be removed by any number of means, including by heating the cast layer, heating the cast layer under heat and pressure, for example by laminating the cast layer to another substrate. In an aspect, articles prepared by the above-described methods can include adhesives, packaging material, capacitor films, or circuit board layers. In an aspect, articles prepared from the curable composition can be a dielectric layer, or a coating disposed on a substrate, for example a wire or cable coating. For example, the article can be a dielectric layer in a circuit material, for example in a printed circuit board, used, for example, in lighting or communications applications. Other exemplary articles prepared from the curable composition can be one or more painted layers. The curable compositions can be used to prepare articles as disclosed herein for other curable thermosetting compositions. [0104] This disclosure is further illustrated by the following examples, which are non- limiting. EXAMPLES [0105] Prophetic Example 1: Preparation of a capped poly(phenylene ether). [0106] In a round bottom flask equipped with a thermocouple, addition funnel, condenser and overhead agitator, isophthalic acid chloride or terephthalic acid chloride and toluene will be added under nitrogen. Upon dissolution of the acid chloride, naphthol and bifunctional hydroxy-terminated poly(phenylene ether) will be added, followed by addition of tetrabutylammonium bromide under nitrogen. The temperature will be raised to 50-60°C and aqueous sodium hydroxide will be added dropwise over several hours. After the addition is completed, the reaction will be monitored for completion. Deionized water will be added, and the reaction mixture will be stirred for 15-30 minutes. The organic layer will be separated, and the activated ester-capped poly(phenylene ether) will be isolated by removal of toluene. Alternatively, the activated ester-capped poly(phenylene ether) can be precipitated into a suitable non-solvent, such as methanol. The product will be dried under vacuum and nitrogen. The structure of the activated ester-capped poly(phenylene ether) can be confirmed, for example, using nuclear magnetic resonance (NMR) spectroscopy. The molecular weight of the activated ester-capped poly(phenylene ether) can be determined using gel permeation chromatography (GPC) relative to polystyrene standards. Alternatively or additionally, the number average molecular weight can be calculated from the degree of polymerization determined using NMR spectroscopy. [0107] This disclosure further encompasses the following aspects. [0108] Aspect 1: A capped poly(phenylene ether) having the structure or wherein Z ¹ , Z ² , Z ³ , and Z ⁴ each independently comprise hydrogen, halogen, unsubstituted or substituted C1-12 primary or secondary hydrocarbyl, C1-12 hydrocarbylthio, C1-12 hydrocarbyloxy, and C2-12 halohydrocarbyloxy wherein at least two carbon atoms separate the halogen and oxygen atoms; R ¹ is a substituted or unsubstituted phenylene group; R ² is a substituted or unsubstituted C6-20 aromatic hydrocarbon group; n is an integer from 4 to 50; x and y are each independently zero to 50, provided that the sum of x and y is 2 to 53; and L is a group of the formula wherein each occurrence of R ³ , R ⁴ , R ⁵ , and R ⁶ independently comprises hydrogen, halogen, unsubstituted or substituted C ₁ - ₁₂ primary or secondary hydrocarbyl, C ₁ - ₁₂ hydrocarbylthio, C ₁ - ₁₂ hydrocarbyloxy, or C2-12 halohydrocarbyloxy wherein at least two carbon atoms separate the halogen and oxygen atoms; z is 0 or 1; and Y has a structure comprising wherein each occurrence of R ⁷ independently comprises hydrogen and C ₁ - ₁₂ hydrocarbyl, and each occurrence of R ⁸ and R ⁹ is each independently hydrogen, C1-12 hydrocarbyl, or C1-6 hydrocarbylene wherein R ⁸ and R ⁹ collectively form a C ₄ - ₁₂ alkylene group, or Y has a structure derived from a hydroxyaryl-diterminated polysiloxane. [0109] Aspect 2: The capped poly(phenylene ether) of aspect 1, wherein the capped poly(phenylene ether) comprises repeating units derived from 2,6-dimethyl phenol. [0110] Aspect 3: The capped poly(phenylene ether) of aspects 1 or 2, wherein each occurrence of R ³ and R ⁴ is methyl, each occurrence of R ⁵ and R ⁶ is hydrogen, z is 1, and Y is an isopropylidene group. [0111] Aspect 4: The capped poly(phenylene ether) of any of aspects 1 to 3, wherein Z ² and Z ³ are each hydrogen and Z ¹ and Z ⁴ are each a unsubstituted or substituted C ₁ - ₁₂ primary hydrocarbyl, preferably methyl. [0112] Aspect 5: The capped poly(phenylene ether) of any of aspects 1 to 4, wherein R ¹ is an unsubstituted phenylene group. [0113] Aspect 6: The capped poly(phenylene ether) of aspect 5, wherein R ¹ is derived from terephthalic acid or isophthalic acid. [0114] Aspect 7: The capped poly(phenylene ether) of any of aspects 1 to 6, wherein R ² comprises a phenyl group, a methyl-substituted phenyl group, a dimethyl- substituted phenyl group, a phenyl-substituted phenyl group, a benzyl-substituted phenyl group, a cumyl- substituted phenyl group, or a naphthyl group. [0115] Aspect 8: The capped poly(phenylene ether) of any of aspects 1 to 7, wherein R ² comprises a phenyl group, or a naphthyl group. [0116] Aspect 9: The capped poly(phenylene ether) of aspect 1, wherein the capped poly(phenylene ether) is of the structure . [0117] Aspect 10: The capped poly(phenylene ether) of aspect 9, wherein R ¹ is a divalent phenylene group; and R ² is a phenyl group or a naphthyl group. [0118] Aspect 11: The capped poly(phenylene ether) of any of aspects 1 to 10, wherein the capped poly(phenylene ether) has a number average molecular weight of 500 to 20,000 g/mol, or 500 to 10,000 g/mol, or 500 to 7,500 g/mol, determined by gel permeation chromatography (GPC) relative to polystyrene standards. [0119] Aspect 12: A method of making the capped poly(phenylene ether) of any of aspects 1 to 11, the method comprising oxidatively polymerizing the monohydric phenol in the presence of a catalyst, and optionally a dihydric phenol, to provide a poly(phenylene ether) having a phenolic end group; and reacting the poly(phenylene ether) with a capping agent under conditions effective to provide the capped poly(phenylene ether). [0120] Aspect 13: A curable thermosetting composition comprising the capped poly(phenylene ether) of any of aspects 1 to 11. [0121] Aspect 14: A cured thermoset composition comprising a cured product of the curable thermosetting composition of aspect 13. [0122] Aspect 15: An article comprising the cured thermoset composition of claim 14, wherein the article is a composite, a foam, a fiber, a layer, a coating, an encapsulant, an adhesive, a sealant, a molded component, a prepreg, a casing, a cast article, a laminate, or a combination thereof; or wherein the article is a metal clad laminate, an electronic composite, a structural composite, or a combination thereof. [0123] The compositions, methods, and articles can alternatively comprise, consist of, or consist essentially of, any appropriate materials, steps, or components herein disclosed. The compositions, methods, and articles can additionally, or alternatively, be formulated so as to be devoid, or substantially free, of any materials (or species), steps, or components, that are otherwise not necessary to the achievement of the function or objectives of the compositions, methods, and articles. [0124] All ranges disclosed herein are inclusive of the endpoints, and the endpoints are independently combinable with each other. “Combinations” is inclusive of blends, mixtures, alloys, reaction products, and the like. The terms “first,” “second,” and the like, do not denote any order, quantity, or importance, but rather are used to distinguish one element from another. The terms “a” and “an” and “the” do not denote a limitation of quantity, and are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. “Or” means “and/or” unless clearly stated otherwise. Reference throughout the specification to “an aspect” means that a particular element described in connection with the aspect is included in at least one aspect described herein, and may or may not be present in other aspects. The term “combination thereof” as used herein includes one or more of the listed elements, and is open, allowing the presence of one or more like elements not named. In addition, it is to be understood that the described elements may be combined in any suitable manner in the various aspects. [0125] Unless specified to the contrary herein, all test standards are the most recent standard in effect as of the filing date of this application, or, if priority is claimed, the filing date of the earliest priority application in which the test standard appears. [0126] Unless defined otherwise, technical and scientific terms used herein have the same meaning as is commonly understood by one of skill in the art to which this application belongs. All cited patents, patent applications, and other references are incorporated herein by reference in their entirety. However, if a term in the present application contradicts or conflicts with a term in the incorporated reference, the term from the present application takes precedence over the conflicting term from the incorporated reference. [0127] Compounds are described using standard nomenclature. For example, any position not substituted by any indicated group is understood to have its valency filled by a bond as indicated, or a hydrogen atom. A dash ("-") that is not between two letters or symbols is used to indicate a point of attachment for a substituent. For example, -CHO is attached through carbon of the carbonyl group. [0128] As used herein, the term “hydrocarbyl”, whether used by itself, or as a prefix, suffix, or fragment of another term, refers to a residue that contains only carbon and hydrogen. The residue can be aliphatic or aromatic, straight-chain, cyclic, bicyclic, branched, saturated, or unsaturated. It can also contain combinations of aliphatic, aromatic, straight chain, cyclic, bicyclic, branched, saturated, and unsaturated hydrocarbon moieties. However, when the hydrocarbyl residue is described as substituted, it may, optionally, contain heteroatoms over and above the carbon and hydrogen members of the substituent residue. Thus, when specifically described as substituted, the hydrocarbyl residue can also contain one or more carbonyl groups, amino groups, hydroxyl groups, or the like, or it can contain heteroatoms within the backbone of the hydrocarbyl residue. The term "alkyl" means a branched or straight chain, saturated aliphatic hydrocarbon group, e.g., methyl, ethyl, n-propyl, i-propyl, n-butyl, s-butyl, t-butyl, n- pentyl, s-pentyl, and n- and s-hexyl. “Alkenyl” means a straight or branched chain, monovalent hydrocarbon group having at least one carbon-carbon double bond (e.g., ethenyl (-HC=CH2)). “Alkoxy” means an alkyl group that is linked via an oxygen (i.e., alkyl-O-), for example methoxy, ethoxy, and sec-butyloxy groups. "Alkylene" means a straight or branched chain, saturated, divalent aliphatic hydrocarbon group (e.g., methylene (-CH ₂ -) or, propylene (-(CH2)3-)). “Cycloalkylene” means a divalent cyclic alkylene group, -CnH2n-x, wherein x is the number of hydrogens replaced by cyclization(s). “Cycloalkenyl” means a monovalent group having one or more rings and one or more carbon-carbon double bonds in the ring, wherein all ring members are carbon (e.g., cyclopentyl and cyclohexyl). "Aryl" means an aromatic hydrocarbon group containing the specified number of carbon atoms, such as phenyl, tropone, indanyl, or naphthyl. “Arylene” means a divalent aryl group. “Alkylarylene” means an arylene group substituted with an alkyl group. “Arylalkylene” means an alkylene group substituted with an aryl group (e.g., benzyl). The prefix "halo" means a group or compound including one more of a fluoro, chloro, bromo, or iodo substituent. A combination of different halo atoms (e.g., bromo and fluoro), or only chloro atoms can be present. The prefix “hetero” means that the compound or group includes at least one ring member that is a heteroatom (e.g., 1, 2, or 3 heteroatom(s)), wherein the heteroatom(s) is each independently N, O, S, Si, or P. “Substituted” means that the compound or group is substituted with at least one (e.g., 1, 2, 3, or 4) substituents that can each independently be a C _1-9 alkoxy, a C _1-9 haloalkoxy, a nitro (-NO ₂ ), a cyano (-CN), a C1-6 alkyl sulfonyl (-S(=O)2-alkyl), a C6-12 aryl sulfonyl (-S(=O)2-aryl), a thiol (-SH), a thiocyano (-SCN), a tosyl (CH ₃ C ₆ H ₄ SO ₂ -), a C _3-12 cycloalkyl, a C _2-12 alkenyl, a C _5-12 cycloalkenyl, a C6-12 aryl, a C7-13 arylalkylene, a C4-12 heterocycloalkyl, and a C3-12 heteroaryl instead of hydrogen, provided that the substituted atom’s normal valence is not exceeded. The number of carbon atoms indicated in a group is exclusive of any substituents. For example - CH ₂ CH ₂ CN is a C ₂ alkyl group substituted with a nitrile. [0129] While particular embodiments have been described, alternatives, modifications, variations, improvements, and substantial equivalents that are or may be presently unforeseen may arise to applicants or others skilled in the art. Accordingly, the appended claims as filed and as they may be amended are intended to embrace all such alternatives, modifications variations, improvements, and substantial equivalents.