Alkoxyamine functionalized Polysulfone-Comb-Copolymers

The present invention relates to alkoxyamine fuctionalized polysulfones, a process for the functionalization of polysulfones with nitroxide initiators and subsequent nitroxide-mediated radical polymerizations to yield polysulfone-graft-copolymers, e.g polysulfone-graft-poly-4- vinylbenzylchloride copolymer. Further aspects of the invention are the polysulfone-graft- copoolymers itself and the use of such polysulfone-graft-copolymers as membranes.

Polysulfones are very stable engineering thermoplastics. However, the molecule generally lacks any usable functionality, rendering polysulfones useful only for applications in which their hydrophobic unreactive state is of advantage, for example, in pipes and moulded forms, as well as membrane materials in the area of liquid and gas separations. There is obviously a need for a process which provides polysulfone-copolymers having improved or modified chemical and physical properties.

Surprisingly it has been found that alkoxyamine-functionalized aromatic polysulfones, including polysulfone ionomers and other derivatives, can be prepared by the nucleophilic addition of ortho-metalated polysulfones to nitroxide initiators. These alkoxyamine- functionalized polysulfones can be used for the nitroxide-mediated radical polymerization of ethylenically unsaturated monomers to yield novel polysulfone-graft-copolymers. The copolymers so produced exhibit improved or modified properties such as hydrophilicity, hydrophobicity, fouling resistance, which can be tailored to a desired end use by controlling the nature and degree of the grafting step. These polysulfone-comb-copolymers may, for example, be used for forming membranes, fibres, sheets and solid structures.

One aspect of the invention is an alkoxyamine-functionalized aromatic polysulfone with a repeating unit of formula (I)

wherein p is O or i ; n is a number from 5 to 10 000;

the R' independently of each other are hydrogen or a group of formula (II), with the proviso that at least each 10 ^th repeating unit contains 1 to 3 groups of formula (II)

;

^* denotes the point of attachment; Y is phenylene, naphthylene or biphenylene, which are unsubstituted or substituted by d-

C ₄ alkoxy, d-C ₄ alkylthio or di(Ci-C ₄ alkyl)amino; the Ri ₂ are independently of each other H, Ci-Ci ₈ alkyl, C ₇ -C ₉ phenylalkyl, C ₃ -Ci ₂ cycloalkyl or

C ₂ -Ci ₂ heterocycloalkyl, which are unsubstituted or substituted by Ci-C ₄ alkoxy, Ci-C ₄ alkylthio or di(Ci-C ₄ alkyl)amino; or the Ri ₂ are phenyl or naphthyl, which are unsubstituted or substituted by Ci-C ₄ alkyl, d-

C ₄ alkoxy, Ci-C ₄ alkylthio or di(Ci-C ₄ alkyl)amino;

Ri ₃ is CrCi ₈ alkyl, C ₇ -C ₉ phenylalkyl, C ₃ -Ci ₂ cycloalkyl or C ₂ -Ci ₂ heterocycloalkyl, which are substituted by Ci-C ₄ alkoxy, Ci-C ₄ alkylthio or di(Ci-C ₄ alkyl)amino; or

Ri3 is phenyl or naphthyl, which are unsubstituted or substituted by Ci-C ₄ alkyl, Ci-C ₄ alkoxy, Ci-C ₄ alkylthio or di(C-ι-C ₄ alkyl)amino;

Z is an nitroxide-functionality of formula (Ilia) or (NIb)

(NIa) (MIb) wherein the Ri, are each independently of one another hydrogen, -OR ₃ , -SR ₃ , -N(R ₃ ) ₂ ; unsubstituted CrCi ₈ alkyl, C ₇ -C ₉ phenylalkyl, C ₃ -Ci ₂ cycloalkyl or C ₂ -Ci ₂ heterocycloalkyl; or Ci-Ci ₈ alkyl, C ₇ -C ₉ phenylalkyl, C ₃ -Ci ₂ cycloalkyl or C ₂ -Ci ₂ heterocycloalkyl, which are substituted by Ci-C ₄ alkoxy, Ci-C ₄ alkylthio or di(Ci-C ₄ alkyl)amino; or phenyl, naphthyl, which are unsubstituted or substituted by Ci-C ₄ alkyl, Ci-C ₄ alkoxy, d-

C ₄ alkylthio or di(Ci-C ₄ alkyl)amino;

R ₃ is hydrogen or Ci-Ci ₈ alkyl; or all Ri form together the residue of a polycyclic cylcoaliphatic ring system or a polycyclic heterocycloaliphatic ring system with at least one trivalent nitrogen atom; the R ₂ are independently of each other phenyl or d-C ₆ alkyl or two together with the linking carbon atom form a C ₅ -C ₆ cycloalkyl group; and

A is a divalent group required to form a cyclic 5-, 6- or 7-membered ring, which may contain a further nitrogen and/or oxygen atom;

X is O or a group of formula (IVa), (IVb) or (IVc)

wherein o is 0 or 1 ; a is 1 to 20;

R ₄ and R ₅ are independently of one another hydrogen, -OR ₆ , -SR ₆ , -N(R ₆ ) ₂ ; unsubstituted CrCi ₈ alkyl, C ₇ -C ₉ phenylalkyl, C ₃ -Ci ₂ cycloalkyl or C ₂ -Ci ₂ heterocycloalkyl; or

Ci-Ci ₈ alkyl, C ₇ -C ₉ phenylalkyl, C ₃ -Ci ₂ cycloalkyl or C ₂ -Ci ₂ heterocycloalkyl, which are substituted by Ci-C ₄ alkoxy, Ci-C ₄ alkylthio or di(Ci-C ₄ alkyl)amino; or phenyl, naphthyl, which are unsubstituted or substituted by Ci-C ₄ alkyl, Ci-C ₄ alkoxy, d-

C ₄ alkylthio or di(Ci-C ₄ alkyl)amino;

R ₆ is Ci-Ci ₈ alkyl or perfluorated Ci-Ci ₈ alkyl.

The alkyl groups in the various substituents may be linear or branched. Examples of alkyl containing 1 to 18 carbon atoms are methyl, ethyl, propyl, isopropyl, butyl, 2-butyl, isobutyl, t- butyl, pentyl, 2-pentyl, hexyl, heptyl, octyl, 2-ethylhexyl, t-octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, hexadecyl and octadecyl.

The perfluorated alkyl groups in the various substituents may be linear or branched.

Examples of perfluorated alkyl groups are 1 ,1 ,1-trifluoromethyl and 1 ,1 ,1 ,2,2- pentafluoroethyl.

C ₇ -C ₉ phenylalkyl is for example benzyl, phenylpropyl, α,α-dimethylbenzyl or α-methylbenzyl.

- A -

C ₃ -Ci ₂ cycloalkyl which is unsubstituted or substituted by 1 , 2 or 3 Ci-C ₄ alkyl groups is typically cycloproply, cyclopentyl, methylcyclopentyl, dimethylcyclopentyl, cyclohexyl, methyl- cylcohexyl.

Ci-Ci ₈ alkyl substituted by di(Ci-C ₄ alkyl)amino is preferably e.g. dimethylamino, diethylamino, 2-dimethylaminoethyl, 2-diethylaminoethyl, 3-dimethylaminopropyl, 3-diethylaminopropyl, 3- dibutylaminopropyl and 4-diethylaminobutyl.

Ci-C ₈ alkoxy and, preferably Ci-C ₄ alkoxy, are typically methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy, pentoxy, isopentoxy, hexoxy, heptoxy or octoxy.

Ci-C ₄ alkylthio is typically thiomethyl, thioethyl, thiopropyl, thioisopropyl, thiobutyl and thioisobutyl.

C ₂ -Ci ₂ heterocycloalkyl is typically 1 ,4-dioxane, tetrahydrofuran, thiophen, furan, oxazole, thiazole, pyran, thiopyran.

Phenyl substituted by 1 , 2 or 3 Ci-C ₄ alkyl or Ci-C ₄ alkoxy is typically methylphenyl, dimethyl- phenyl, trimethylphenyl, t-butylphenyl, di-t-butylphenyl, 3,5-di-t-butyl-4-methylphenyl, methoxyphenyl, ethoxyphenyl and butoxyphenyl.

Examples of polycyclic cylcoaliphatic ring systems are adamantane, cubane, twistane, norbornane, bicyclo[2.2.2]octane or bicylco[3.2.1]octane.

An example of a polycyclic heterocycloaliphatic ring system is hexamethylentetramine (urotropine).

Examples for a divalent group A required to form a cyclic 5-, 6- or 7-membered ring are: C ₂ - C ₄ alkylene, 1 ,2 phenylene which groups may be unsubstituted or substituted by d- Ci ₈ alkoxy, Ci-Ci ₈ alkylthio or di(Ci-Ci ₈ alkyl)amino or phenyl.

When A has the meaning of C ₂ -C ₄ alkylene, these groups may be also interrupted by an O atom.

C ₂ -C ₄ alkylene bridges interrupted by at least one O atom are, for example,

-CH ₂ -O-CH ₂ -CH ₂ -, CH ₂ -O-CH ₂ -, -0-CH ₂ -CH ₂ -, -0-CH ₂ -O-CH ₂ - or -0-CH ₂ .

The C atom to which the substituents Ri are bound is preferably a secondary or tertiary C atom, more preferably it is a tertiary C atom.

For example the alkoxyamine-functionalized aromatic polysulfone has a repeating unit of formula (Ia)

wherein n is a number from 5 to 10 000; m is a number from 0 to 10 000; and m + n is a number from 5 to 10 000; the R' independently of each other are hydrogen or a group of formula (II), with the proviso that at least each 10 ^th repeating unit contains 1 to 3 groups of formula (II)

^* denotes the point of attachment;

Y is unsubstituted phenylene, naphthylene or biphenylene; the Ri ₂ are independently of each other H or CH ₃ ; Ri3 is Ci-C ₄ alkyl; Z is an nitroxide-functionality of formula (Ilia) or (NIb)

(NIa) (MIb) wherein the R-i, are each independently of one another hydrogen, -OR ₃ , unsubstituted Ci-Ci ₈ alkyl or C ₅ -C ₇ cycloalkyl; or phenyl, which is unsubstituted or substituted by Ci-C ₄ alkyl, d-C ₄ alkoxy or di(C _r C ₄ alkyl)amino;

R ₃ is Ci-C ₈ alkyl; the R ₂ are independently d-C ₆ alkyl;

A is a divalent group required to form a cyclic 5-, 6- or 7-membered ring, which may contain a further nitrogen and/or oxygen atom; and

X is O or a group of formula (IVa), (IVb) or (IVc)

wherein o is 0 or 1 ; a is 1 to 20;

R ₄ and R ₅ are independently of one another hydrogen, -OR ₆ , -SR ₆ , -N(R ₆ ) ₂ ; unsubstituted CrCi ₈ alkyl, C ₇ -C ₉ phenylalkyl, C ₃ -Ci ₂ cycloalkyl or C ₂ -Ci ₂ heterocycloalkyl; or

Ci-Ci ₈ alkyl, C ₇ -C ₉ phenylalkyl, C ₃ -Ci ₂ cycloalkyl or C ₂ -Ci ₂ heterocycloalkyl, which are substituted by Ci-C ₄ alkoxy, Ci-C ₄ alkylthio or di(Ci-C ₄ alkyl)amino; or phenyl, naphthyl, which are unsubstituted or substituted by Ci-C ₄ alkyl, Ci-C ₄ alkoxy, d-

C ₄ alkylthio or di(C-ι-C ₄ alkyl)amino;

R ₆ is Ci-Ci ₈ alkyl or perfluorated Ci-Ci ₈ alkyl.

Preferred is an alkoxyamine-functionalized aromatic polysulfone wherein the repeating unit is of formula (Ia)

wherein n is a number from 5 to 10 000; m is a number from 0 to 10 000; and m + n is a number from 5 to 10 000;

the R' independently of each other are hydrogen or a group of formula (II), with the proviso that at least each 10 ^th repeating unit contains 1 to 3 groups of formula (II)

; wherein Y is phenylene, naphthylene or biphenylene; one Ri ₂ is H and the other R ₁₂ is CH ₃ ;

Z is an nitroxide-functionality of formula (Ilia) or (NIb)

(NIa) (1Mb) wherein the group the R ₂ are independently CrC ₆ alkyl;

A is a divalent group required to form a cyclic 5-, 6- or 7-membered ring, which may contain a further nitrogen and/or oxygen atom; X is O or of formula (IVa) or (IVb)

wherein o is 0 or 1 ;

R ₄ and R ₅ are independently of one another hydrogen or -OR ₆ ; unsubstituted CrC ₁₈ alkyl, C ₇ -C ₉ phenylalkyl, C ₃ -C ₁₂ cycloalkyl or C ₂ -C ₁₂ heterocycloalkyl; or phenyl, naphthyl, which are unsubstituted; and R ₆ is CrC ₄ alkyl or perfluorated Ci-C ₄ alkyl.

In a specific embodiment the alkoxyamine-functionalized aromatic polysulfone has the repeating unit of formula (Ia)

wherein n is a number from 5 to 10 000; m is a number from 0 to 10 000; and m + n is a number from 5 to 10 000; the R' independently of each other are hydrogen or a group of formula (II), with the proviso that at least each 10 ^th repeating unit contains 1 to 3 groups of formula (II)

wherein Y is phenylene; one Ri ₂ is H and the other R ₁₂ is CH ₃ ;

Z is an nitroxide-functionality of formula (NIc)

(MIc) wherein D is H, =O, OR ₁₀ or NR ₁₀ Rn;

Rio and Rn independently are phenyl, d-Ci ₈ alkyl or, if D is NR ₁₀ R ₁₁ , taken together, form a C ₂ -C ₁₂ alkylene bridge interrupted by at least one O atom; X is of formula (IVa)

R ₄ _

- ⁰ λ _^ Jt\\^h ⁰ - ^(IVa)

R ₅ wherein o is 0 or 1 ;

R ₄ and R ₅ are independently of one another hydrogen or unsubstituted Ci-C ₄ alkyl or perfluorated Ci-C ₄ alkyl.

Preferred is an alkoxyamine-functionalized aromatic polysulfone wherein in the formula of group IVa o is 1 and R ₄ and R ₅ are independently of each other CH ₃ or CF ₃ .

Another aspect of the invention is a process for the preparation of an alkoxyamine- functionalized aromatic polysulfone as described above, which process comprises a) metalating a polysulfone with a repeating unit of formula (X)

(X) to yield a polysulfone of formula (Xl)

(Xl) wherein b is 0 or 1 ;

Me is the metal of a metalating agent, which is attached such that at least each 10 ^th repeating unit contains 1 to 3 metal atoms; b) quenching the metalated polysulfone with an alkoxyamine of formula (Na)

to obtain an alkoxyamine-functionalized aromatic polysulfone of formula (I)

wherein the substituents are as defined above.

The metalating agent may be n-butyllithium, sec-butyllithium, iso-butyllithium, tert- butyllithium, methyllithium, ethyllithium, propyllithium, phenyllithium or lithium diisopropylamide, with n-butyllithium being preferred.

Typically the polysulfone may be metalated by,

(a1 ) dissolving or suspending the polysulfone in a solvent which is substantially not reactive with the metalating agent and the polysulfone,

(a2) cooling the solution to a temperature not greater than about 30 ⁰ C, (a3) adding the metalating agent under anhydrous conditions while continuing the cooling of the solution to the said temperature, and

(a4) allowing the metalating agent to react with the polysulfone.

Metalating reactions are in principal known and, for example, described in Membrane Formation and Modification, I Pinnau and B. D. Freeman, (1999) ACS Symposium Series 744, pp. 146 ff.

Conveniently, the reaction will be carried out under an inert atmosphere, such as argon or nitrogen.

The reaction temperature for steps (a2), (a3) and (a4) may be in the range of about -10 ⁰ C to about -80°C. Preferably, the reaction temperature for these steps is in the range of about -40 ⁰ C to about -80 ⁰ C. At higher temperatures, while metalation likely will occur, other competing reactions also tend to occur, with formation of precipitated insoluble products.

The degree of metalation/lithiation is controlled by the stoichiometric amount (molar ratio) of the lithiating agent used. Generally, from one to about three aromatic ring sites are lithiated. This may also be referred to as Degree of Substitution (DS). The degree of substitution, therefore, is preferably from 1 to 3 per repeating unit.

The solvent may be tetrahydrofuran, diethylether, hexane, dimethyl ethylene glycol or other suitable solvents.

A further aspect of the inventions is a polymerizable composition comprising a) at least one ethylenically unsaturated monomer b) an alkoxyamine-functionalized aromatic polysulfone as described above.

Also an aspect of the invention is a process for the preparation of an aromatic polysulfone comb copolymer comprising

a) reacting an alkoxyamine-functionalized aromatic polysulfone as described above with an ethylenically unsaturated monomer at a temperature between 60° C and 180° C; b) cooling the reaction mixture to a temperature below 60° C; and c) optionally isolating the resulting aromatic polysulfone comb copolymer.

Suitable alkoxyamine-functionalities and polysulfones and examples of different groups and substituents are already mentioned above including their preferences.

Typically the amount of the alkoxyamine-functionalized aromatic polysulfone of formula (I) is in the range of 0.01 mol% to 30mol% based on the monomer, oligomer or monomer/oligomer mixture used.

If monomer mixtures are used the average molecular weight is taken for calculating mol%.

The monomers suitable for use in the present invention may be water-soluble or water- insoluble. Water soluble monomers contain typically a salt of a carboxylic acid group. Water insoluble monomers are typically free of acid and phenolic groups. Typical metal atoms are Na, K or Li.

Typically monoethylenically unsaturated monomers free of carboxylic acid and phenolic groups are suitable for this invention include the alkyl esters of acrylic or methacrylic acids such as methyl acrylate, ethyl acrylate, butyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate and isobutyl methacrylate; the hydroxyalkyl esters of acrylic or methacrylic acids, such as hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxyethyl methacrylate, and hydroxypropyl methacrylate; acrylamide, methacrylamide, N-tertiary butylacrylamide, N-methylacrylamide, N,N-dimethylacrylamide; acrylonitrile, methacrylonitrile, allyl alcohol, dimethylaminoethyl acrylate, dimethylaminoethyl methacrylate, phosphoethyl methacrylate, N-vinylpyrrolidone, N-vinylformamide, N-vinylimidazole, vinyl acetate, conjugated dienes such as butadiene or isoprene, styrene, styrenesulfonic acid salts, vinylsulfonic acid salts and 2-acrylamido-2-methylpropane-sulfonic acid salts and acryloil chloride.

Preferred ethylenically unsaturated monomers are selected from the group consisting of ethylene, propylene, n-butylene, i-butylene, styrene, substituted styrene, conjugated dienes,

acrolein, vinyl acetate, vinylpyrrolidone, vinylimidazole, maleic anhydride, (alkyl)acrylic acidanhydrides, (alkyl)acrylic acid salts, (alkyl)acrylic esters, (meth)acrylonitriles, (alkyl)acrylamides, vinyl halides and vinylidene halides.

Particularly preferred ethylenically unsaturated monomers are styrene, 4-vinylbenzylchloride, α-methyl styrene, p-methyl styrene, butadiene, methylacrylate, ethylacrylate, propylacrylate, n-butyl acrylate, tert. -butyl acrylate and acrylnitril.

In a most preferred composition the ethylenically unsaturated monomer is 4-vinylbenzyl- chloride.

In another embodiment of the invention the ethylenically unsaturated monomer is typically ethylene, propylene, n-butylene, i-butylene, isoprene, 1 ,3-butadiene, α-C ₅ -Ci ₈ alkene, styrene, α-methyl styrene, p-methyl styrene or a compound of formula CH ₂ =C(Ra)-(C=Z)-R _b , wherein R _a is hydrogen or d-C ₄ alkyl, R _b is NH ₂ , 0 ^" (Me ⁺ ), glycidyl, unsubstituted d- Ci ₈ alkoxy, C ₂ -Ciooalkoxy interrupted by at least one N and/or O atom, or hydroxy-substituted CrCi ₈ alkoxy, unsubstituted Ci-Ci ₈ alkylamino, di(Ci-Ci ₈ alkyl)amino, hydroxy-substituted d- Ci ₈ alkylamino or hydroxy-substituted di(Ci-Ci ₈ alkyl)amino, -O-CH ₂ -CH ₂ -N(CH ₃ ) ₂ or -0-CH ₂ - CH ₂ -N ⁺ H(CHa) ₂ An ^" ; An ^" is a anion of a monovalent organic or inorganic acid; Me is a monovalent metal atom or the ammonium ion; Z is oxygen or sulfur.

Typically R ₃ is hydrogen or methyl, R _b is NH ₂ , gycidyl, unsubstituted or with hydroxy substituted Ci-C ₄ alkoxy, unsubstituted Ci-C ₄ alkylamino, di(Ci-C ₄ alkyl)amino, hydroxy- substituted Ci-C ₄ alkylamino or hydroxy-substituted di(C-ι-C ₄ alkyl)amino;and Z is oxygen.

Specific ethylenically unsaturated monomers are styrene, methylacrylate, ethylacrylate, butylacrylate, isobutylacrylate, tert. butylacrylate, hydroxyethylacrylate, hydroxypropyl- acrylate, dimethylaminoethylacrylate, glycidylacrylates, methyl(meth)acrylate, ethyl(meth)- acrylate, butyl(meth)acrylate, hydroxyethyl(meth)acrylate, hydroxypropyl(meth)acrylate, dimethylaminoethyl(meth)acrylate, glycidyl(meth)acrylates, acrylonitrile, acrylamide, methacrylamide or dimethylaminopropyl-methacrylamide.

Preferred acrylates are methylacrylate, ethylacrylate, butylacrylate, isobutylacrylate, tert. butylacrylate, hydroxyethylacrylate, hydroxypropylacrylate, dimethylaminoethylacrylate, glycidylacrylates, methyl(meth)acrylate, ethyl(meth)acrylate, butyl(meth)acrylate, hydroxyl- ethyl(meth)acrylate, hydroxypropyl(meth)acrylate, dimethylaminoethyl(meth)acrylate, glycidyl(meth)acrylates, acrylonitrile, acrylamide or methacrylamide.

Examples for C ₈ -Ci ₆ ethylenically unsaturated phenolics, which may also be used as comonomers include 4-hydroxy styrene, 4-hydroxy-α-methyl styrene, and 2,6-di-tert. butyl, 4- vinyl phenol.

Another class of carboxylic acid monomers suitable for use as comonomers in this invention are the alkali metal and ammonium salts of C ₄ -C6-ethylenically unsaturated dicarboxylic acids. Suitable examples include maleic acid, maleic anhydride, itaconic acid, mesaconic acid, fumaric acid and citraconic acid. Maleic anhydride and itaconic acid are the preferred monoethylenically unsaturated dicarboxylic acid monomer(s).

The acid monomers suitable for use in this invention are in the form of the alkali metal salts or ammonium salts of the acid.

The polymerizable composition of the present invention may additionally comprise a solvent selected from the group consisting of water, alcohols, esters, ethers, ketones, amides, sulfoxides, hydrocarbons and halogenated hydrocarbons.

The polymerization process may be carried out in the presence of an organic solvent or in the presence of water or in mixtures of organic solvents and water. Additional cosolvents or surfactants, such as glycols or ammonium salts of fatty acids, may be present. Other suitable cosolvents are described hereinafter.

Preferred processes use as little solvents as possible. In the reaction mixture it is preferred to use more than 30% by weight of monomer and initiator, particularly preferably more than 50% and most preferrably more than 80%.

If organic solvents are used, suitable solvents or mixtures of solvents are typically pure alkanes (hexane, heptane, octane, isooctane), hydrocarbons (benzene, toluene, xylene),

halogenated hydrocarbons (chlorobenzene), alkanols (methanol, ethanol, ethylene glycol, ethylene glycol monomethyl ether), esters (ethyl acetate, propyl, butyl or hexyl acetate) and ethers (diethyl ether, dibutyl ether, ethylene glycol dimethyl ether), or mixtures thereof.

The aqueous polymerization reactions can be supplemented with a water-miscible or hydrophilic cosolvent to help ensure that the reaction mixture remains a homogeneous single phase throughout the monomer conversion. Any water-soluble or water-miscible cosolvent may be used, as long as the aqueous solvent medium is effective in providing a solvent system which prevents precipitation or phase separation of the reactants or polymer products until after all polymerization reactions have been completed. Exemplary cosolvents useful in the present invention may be selected from the group consisting of aliphatic alcohols, glycols, ethers, glycol ethers, pyrrolidines, N-alkyl pyrrolidinones, N-alkyl pyrrolidones, polyethylene glycols, polypropylene glycols, amides, carboxylic acids and salts thereof, esters, organosulfides, sulfoxides, sulfones, alcohol derivatives, hydroxyether derivatives such as butyl carbitol or cellosolve, amino alcohols, ketones, and the like, as well as derivatives thereof and mixtures thereof. Specific examples include methanol, ethanol, propanol, dioxane, ethylene glycol, propylene glycol, diethylene glycol, glycerol, dipropylene glycol, tetrahydrofuran, and other water-soluble or water-miscible materials, and mixtures thereof. When mixtures of water and water-soluble or water-miscible organic liquids are selected as the aqueous reaction media, the water to cosolvent weight ratio is typically in the range of about 100:0 to about 10:90.

When monomer mixtures or monomer/oligomer mixtures are used, the calculation of mol-% is based on an average molecular weight of the mixture.

Hydrophilic monomers, polymers and copolymers of the present invention can be separated from one another or from the polymerization reaction mixture by, for example, changing the pH of the reaction media and by other well known conventional separation techniques.

The polymerization temperature may range from about 5O ⁰ C to about 18O ⁰ C, preferably from about 8O ⁰ C to about 15O ⁰ C. At temperatures above about 18O ⁰ C, the controlled conversion of the monomer into polymers decreases, and uncertain and undesirable by-products, such as thermally initiated polymers are formed or destruction of the polymerization regulator may

occur. Frequently, these by-products discolor the polymer mixture and a purification step may be required to remove them, or they may be intractable.

The reaction is typically carried out at ambient pressure. Reaction times are typically from 30 minutes to 20 hours.

The high reactivity of the present initiators, which are already active at relatively low temperatures leads in principal to shorter reaction times. The resulting polymers are usually colourless and they can be used in most cases without any further purification step. This is an important advantage when industrial scale-up is considered.

After the polymerizing step is complete, the formed (co)polymer obtained is isolated. The isolating step of the present process is conducted by known procedures, e.g. by distilling off the unreacted monomer or by precipitation in a suitable nonsolvent, filtering the precipitated polymer followed by washing and drying the polymer.

Furthermore, block copolymers of this invention, wherein the blocks alternate between polar monomers and non-polar monomers, are useful in many applications as amphiphilic surfactants or dispersants for preparing highly uniform polymer blends.

Random copolymers and tapered copolymer structures can be synthesized as well by using a mixture of monomers or adding a second monomer before the first one is completely consumed.

The (co)polymers of the present invention may have a number average molecular weight from 1 000 to 400 000 g/mol, preferably from 2 000 to 250 000 g/mol and, more preferably, from 2 000 to 200 000 g/mol. When produced in bulk, the number average molecular weight may be up to 500 000 (with the same minimum weights as mentioned above). The number average molecular weight may be determined by size exclusion chromatography (SEC), gel permeation chromatography (GPC), matrix assisted laser desorption/ionization mass spectrometry (MALDI-MS) or, if the initiator carries a group which can be easily distinguished from the monomer(s), by NMR spectroscopy or other conventional methods.

Because the present polymerizaton is a "living" polymerization, it can be started and stopped practically at will. Furthermore, the polymer product retains the functional alkoxyamine group

allowing a continuation of the polymerization in a living matter. Thus, in one embodiment of this invention, once the first monomer is consumed in the initial polymerizing step a second monomer can then be added to form a second block on the growing polymer chain in a second polymerization step. Therefore it is possible to carry out additional polymerizations with the same or different monomer(s) to prepare multi-block copolymers.

Furthermore, since this is a radical polymerization, blocks can be prepared in essentially any order. One is not necessarily restricted to preparing block copolymers where the sequential polymerizing steps must flow from the least stabilized polymer intermediate to the most stabilized polymer intermediate, such as is the case in ionic polymerization. Thus it is possible to prepare a multi-block copolymer in which a polyacrylonitrile or a poly(meth)acrylate block is prepared first, then a styrene or butadiene block is attached thereto, and so on.

The polysulfone-comb-copolymers have the following idealized structure with a repeating unit of formula (Ic)

wherein p is 0 or 1 ; n is a number from 5 to 10 000; the substituents pol independently of each other denote hydrogen or a oligomer or polymer derived from an ethylenically unsaturated monomer, with the proviso that at least each 10 ^th repeating unit contains 1 to 3 oligomer or polymer groups X is O or a group of formula (IVa), (IVb) or (IVc)

wherein o is 0 or 1 ; a is 1 to 20;

R ₄ and R ₅ are independently of one another hydrogen, -OR ₆ , -SR ₆ , -N(R ₆ ) ₂ ; unsubstituted CrCi ₈ alkyl, C ₇ -C ₉ phenylalkyl, C ₃ -Ci ₂ cycloalkyl or C ₂ -Ci ₂ heterocycloalkyl; or

Ci-Ci ₈ alkyl, C ₇ -C ₉ phenylalkyl, C ₃ -Ci ₂ cycloalkyl or C ₂ -Ci ₂ heterocycloalkyl, which are substituted by Ci-C ₄ alkoxy, Ci-C ₄ alkylthio or di(Ci-C ₄ alkyl)amino; or phenyl, naphthyl, which are unsubstituted or substituted by Ci-C ₄ alkyl, Ci-C ₄ alkoxy, d-

C ₄ alkylthio or di(CrC ₄ alkyl)amino; and

R ₆ is Ci-Ci ₈ alkyl or perfluorated Ci-Ci ₈ alkyl.

Preferably the substituents pol, when they have the meaning of an oligomer or polymer derived from an ethylenically unsaturated monmer have an average number molecular weight from 10 to 10 000, in particular from 100 to 5000.

In a specific embodiment the substituent pol has a repeating unit of the following structure.

wherein n is a number from 10 to 10 000; R" is hydrogen or methyl and R'" is hydrogen or Ci-C ₈ alkyl. The repeating unit may also be in the form of a salt with a polymeric anion. In this case R'" has the meaning of the ammonium cation or of a cation of an alkali metal, such as Li, Na or K.

It is, for example, also possible to polymerize an acrylic acid ester as the comb copolymer and in a further step to hydrolyze the ester in a polymer analogous reaction to give the free acid.

The polysulfone-comb-copolymers prepared by the present invention are particularly useful for following applications: membranes, adhesives, detergents, dispersants, emulsifiers, surfactants, defoamers, adhesion promoters, corrosion inhibitors, viscosity improvers, lubricants, rheology modifiers, thickeners, crosslinkers, paper treatment, electronic materials, paints, coatings, photography, ink materials, imaging materials, superabsorbants, cosmetics, hair products, preservatives, biocide materials or modifiers for asphalt, leather, textiles, ceramics and wood.

The aromatic polysulfone comb copolymers are particularly useful as membrane material.

The above mentioned applications can be formed by melt processing, casting or spraying.

The following examples illustrate the invention.

Materials and methods Udel ^® P1700 (Polysulfone from Solvay Advanced Polymers GmbH) is dried in vacuo at 110 ⁰ C for 24 h prior to use. Reagent grade chemicals are used as received. The alkoxyamine of formula (V)

is prepared according to WO 99/46261. Lithiation reactions are performed under an inert atmosphere of dry nitrogen in glassware that had been dried overnight at 1 10 ⁰ C. n- Butyllithium (2.5 m) hexane solution and other reagent grade chemicals are used as received. 4-Vinylbenzylchloride is passed through a column of alkaline aluminium oxide prior to use and t-butylacrylate is distilled in vacuo prior to use. 2,2,6,6-Tetramethylpiperidine-1-

oxyl radical (TEMPO) is used as received. Tetrahydrofuran (THF) is distilled over sodium under nitrogen. Elemental analysis is performed on a Leco CHNS-932.

A) Preparation Examples Example A1 : Functionalization of polysulfone (DS = 0.2)

A solution of polysulfone (30.0 g) in THF (410 ml) is cooled to -30 ⁰ C by immersion in a dry- ice/acetone bath. n-Butyllithium is added dropwise till the color changed from colorless to slightly yellow. Then n-butyllithium (12.3 ml) is added dropwise using a syringe. It is stirred by a mechanical stirrer for 30 min after n-butyllithium addition. A solution of the alkoxyamine of formula (V) (10.3 g) in THF (55 ml) is added and the reaction mixture is stirred at -30 ⁰ C for 24 h, quenched by the addition of isopropanol and the alkoxyamine-functionalized polysulfone is precipitated out of ethanol (95%), filtered and subsequently washed with warm ethanol (50 ⁰ C) and water (50 ⁰ C) to remove residual organic impurities and residual lithium salts. The functionalized polymer is dried at 50°C in a vacuum oven. Yield = 34.3 g; DS = 0.2 (elemental analysis); elemental analysis: N 0.51 % , S 6.09%.

Example A2: Functionalization of polvsulfone (DS = 0.4)

A solution of polysulfone (2.2 g) in THF (120 ml) is cooled to -30°C by immersion in a dry- ice/acetone bath. n-Butyllithium is added dropwise till the color changed from colorless to slightly yellow. Then n-butyllithium (1.1 ml) is added dropwise using a syringe. It is stirred by a mechanical stirrer for 30 min after n-butyllithium addition. A solution of the alkoxyamine of formula (V) (0.91 g) in THF (5 ml) is added and the reaction mixture is stirred at -30°C for 24 h. It is quenched by the addition of isopropanol and the alkoxyamine-functionalized polysulfone is precipitated out of ethanol (95%), filtered and subsequently washed with warm ethanol (50°C) and water (50°C) to remove residual organic impurities and residual lithium 2.7 g; DS = 0.4 (elemental analysis); elemental analysis: N 0.84% , S 4.96%.

Example A3: Polymerization of t-butyl acrylate

Alkoxyamine-functionalized polysulfone (DS = 0.2) (2.0 g) and 2,2,6,6-tetramethylpiperidine- 1-oxyl radical (TEMPO) (30 mg) are dissolved in 1-methyl-2-pyrrolidinone (NMP) (40 ml), t- Butyl acrylate (40 ml) is added, the solution is degassed by three freeze-thaw-cycles and sealed under nitrogen. The polymerization mixture is heated up to 130 ⁰ C for 4 h and the polysulfone-comb-copolymer is precipitated from ethanol. Finally the copolymer is dried in a high vacuum drying cabinet. Yield: 3.6 g.

Example A4: Polymerization of 4-vinylbenzylchloride

Alkoxyamine-functionalized polysulfone (DS = 0.3) (0.5 g) and alkoxyamine of formula (V) (21 mg) are dissolved in anisole (4 ml). 4-Vinylbenzylchloride (2 ml) is added, the solution is degassed by three freeze-thaw-cycles and sealed under nitrogen. The polymerization mixture is heated up to 125°C for 1 h and the polysulfone-comb-copolymer is precipitated from ethanol. Finally the copolymer is dried in a high vacuum drying cabinet. Yield: 1.3 g.

B) Application Examples

Example B1 : Preparation of Anti-fouling blend membranes

Blend membranes are prepared by typical non-solvent phase inversion method. Polyethersulfone (PES) (14 g) is dissolved in n-dimethyl pyrrolidone (NMP) (41 g) at 60 ⁰ C for 2 hours. Required amounts of copolymer synthesized according to Example A3 (to make membrane solutions with the copolymer/PES ratio of 1 , 3 and 5 wt%) are completely dissolved in 10 g NMP. These homogenous solutions were added to the polymer solution and stirred at least for 1 hour until a homogenous solution is obtained. Polyethylene glycol- 400 (34 g) is added to the mixture above and stirred for 1 hour. After obtaining homogeneous solution, the casting solutions are left overnight to allow complete release of bubbles. The solution is cast onto a glass plate with a steel Gardner knife at a wet thickness of 200 μm and immersed in a coagulation bath of milli-Q water. The formed membranes are peeled off and subsequently washed with copious amount of water to remove solvents and other organic residues. To obtain the membrane with acrylic acid functionalities (polysulfone-comb- polyacrylic acid copolymer) membrane is cleaved in a mixture of tri-fluoroacetic acid and formic acid (v/v=1/4) for 24 hours. After hydrolysis membranes are washed milli-q water. Microstructure of modified membrane is consistent with morphology of one for ultrafiltration membranes. X-ray photoelectron spectroscopy (XPS) results showes satisfactory inclusion of additive and its preferential segregation to the surface of membrane.

Example B2: Bioadhesion properties

Ultrafiltration blend membranes using polyethersulfone are made in a method similar to that described in Example B1. Biofilms of Pseudomonas aeruginosa are grown on the membranes of 1.27 cm diameter using batch-flow biofilm reactor for 24/48/72 hr. The amount of formed biofilm is estimated using a standard phenol-sulfuric acid carbohydrate assay. For

each sample four specimens are tested. Antifouling blended membranes prepared by the method described in Example B1 (with copolymer/PES ratio of 1wt% in the membrane solution) showed up to 30% less biofilm growth (after 72 hours) than control PES membrane.