| 摘要 |
An arylpolysiloxane having an intrinsic viscosity in benzene at 25 DEG C. of at least 0.05 dl./g. and the configuration <FORM:1089664/C3/1> wherein each R is an aryl radical and n is at least 25, can be made by hydrolysing a polysiloxane having a greater number of recurring units than the above formulated polymer and an intrinsic viscosity in benzene at 25 DEG C. of at least 0.1 dl./g., the hydrolysis being effected in the presence of water, a basic amine catalyst and tetrahydrofuran as solvent. Catalysts specified are piperidine, 1,4-diazobicyclo-2,2,2-octane, triethanolamine, tetramethylguanidine, ethylenediamine and cyclohexylamine. In a typical Example (1) a phenylsilsesquioxane ladder polymer was dissolved in tetrahydrofuran and glacial acetic acid (to neutralize polymerization catalyst); water, piperidine and tetrahydrofuran were then added with stirring and after 20 mins. at 22-24 DEG C. the hydrolysis was stopped by adding glacial acetic acid; benzene was then added and the mixture was poured into water, allowed to separate into 2 layers and the upper layer was separated, washed with aqueous citric acid and then with water and the product was precipitated from the benzene solution with methanol and purified to yield a polymer of the above formula wherein R is phenyl and n is 190. |
