Arylenecyclosiloxane-dimethylsiloxane copolymers

The heterofunctional condensation reaction of 1,4-bis(phenyldichlorosilyl)b enzene with dihydroxydiphenylsilane at a 1:4 ratio of initial compounds in the presence of pyridine was investigated and tetrakis(hydroxydiphenylsilox y)-1,4-bis(phonylsilyl)benzene was obtained. The heterofunctional condensat ion of the tetrakis(hydroxydiphenylsiloxy)-1,4-bis(phenylsilyl)benzene with organotrichlorosilanes at a 1:2 ratio of initial compounds in the presence of pyridine produced dichloro-containing arylenecyclosiloxanes. The dichlo ro-containing arylenecyclosiloxanes were obtained in one stage by successiv e heterofunctional condensation of 1,4-bis(dichlorophenylsilyl)benzene with dihydroxydiphenylsilane and organotrichlorosilanes in a 1:4:2 ratio in the presence of pyridine. It was established that the yields of dichloro-conta ining products were lower. Hydrolysis of dichloroarylenecyclosiloxanes in a neutral condition produced corresponding dihydroxy compounds. Heterofuncti onal polycondensation of dicloro(dihydroxy)arylenecyclosiloxanes with alpha ,omega -dihydroxy(bisdimethylamino)dimethylsiloxanes was used to obtain ary lenecyclosiloxane-dimethylsiloxane copolymers. Thermogravimetric, thermomec hanical, and roentgenographic investigations of the synthesized copolymers were carried out. (C) 2001 John Wiley & Sons, Inc.