To form a silsesquioxane-containing polymer having a pentacyclo[9.5.1.13,9.15,15.1.7,13]octasiloxane skeleton represented by a specified formula and having excellent heat resistance.
A cyclic polysiloxane compound represented by the formula: (HSiO3/2)8 and an unsubstituted or mono-substituted acetylene represented by formula I (wherein R is H, a monovalent organic or organosilicon group) (e.g. phenylcetylene) in amounts to give a molar ratio of 2/1 to 1/4 are dissolved in a solvent (e.g. toluene). Next, a toluene solution of a platinum-containing catalyst (e.g. platinumdivinylsiloxane) is added to the above solution, and the resulting mixture is agitated at room temperature for a specified time to effect polymerization through hydrosilylation. After the reaction, the formed polymer is withdrawn to obtain a silsesquioxane-containing polymer having a pentacyclo[9.5.1.13,9.15,15.17,13]octasiloxane skeleton represented by formula II (wherein m and m1 are each 2, 3, 4 or 5; and n and n1 is 0 or a positive integer) and having a degree of polymerization of about 5-20,000.
HAYASHI TERUYUKI
TANAKA MASATO
