ONE-STEP SYNTHESIS OF THERMOPLASTIC PHENYLSILSESQUIOXANE POLYMER AND ITS COPOLYMERS WITH DIPHENYLSILOXANES

The preparation of reversibly softening polymers and copolymers of phe nylsilsesquioxane in a one-step synthesis has been studied. The synthe tic methods are based on hydrolytic polycondensation of PhSiCl3 or cop olycondensation of PhSiCl3 with Ph2SiCl2 using moistened or hydrated s alts: (1) moistened Na2CO3, K2CO3, (2) Na2B4O7. 10H(2)O, (3) Na3PO4. 1 2H(2)O. Syntheses (1) and (2) pave products as reversibly softening an d soluble materials, whereas synthesis (3) produced partially cross-li nked resins from which a soluble material might be extracted. Polycond ensation using borax gave polymers and copolymers with incorporated bo ron atoms. The polysilsequioxanes were characterized by size exclusion chromatography (SEC), H-1 and Si-29 NMR, IR spectroscopy, and element al analysis. Thermal properties were studied by DSC and thermogravimet ry.