Polysiloxane–POSS systems as precursors to SiCO ceramics

摘要: Abstract In the work, two linear polysiloxanes (D2V and V3 polymers) containing vinyl (Vi) groups regularly distributed along their chains were cross-linked by hydrosilylation with Si H polyhedral oligomeric silsesquioxane (POSS) molecules, namely: dimethylsiloxy-substituted octahedral oligosilsesquioxane ( Q 8 M ). The reactions carried out at equimolar Vi: ratios in methylene chloride, tetrahydrofuran toluene order find optimum solvent for achieving highest possible polymer cross-linking levels. toluene, was also performed lower reactive molar ratios. Investigation of systems allowed establishing that most efficient. Independently ratio starting reaction medium, D2V reacted to a higher extent than one. some systems, acted not only as cross-linker, but filler. Pyrolysis polymers conducted Ar atmosphere led formation SiCO ceramics high yields (63.4–85.1 wt.%). Particularly advantageous effect incorporation POSS molecules on ceramic yield observed polymer. materials obtained are pore- crack-free can be applied chemically thermally stable protective layers various substrates.