Preparation And Properties Of Polytitanium(octyl)siloxane

Octyltriethoxysilanol and vinyltriethoxysilanol were preparated by hydrolysis polymerization.Polytitanosiloxane and polytitanium(vinyloctyl)siloxane were preparated by the two silanols and tetrabutyl titanate.The structures and Mn of the product were analyzed by FT-IR,1H-NMR,13C-NMR and GPC;the OH-groups were investigated by chemical titration;The performance was analyzed by DSC,Dynamic viscometer and TGA.The influencing factors of octyltriethoxysilanol such as reaction temperature and time,solvent,pH and rotating speed on synthesis were also systematically studied.The influencing factors of vinyltriethoxysilanol:molar ratio of the two silanols,amount of hydrolysis acid,reaction time and solvent ratio.The influencing factors of polytitanosiloxane:reaction temperature and time,solvent type,silicon/titanium molar ratio and experimental method.It is intended to provide a basis for the synthesis of polymers with great heat resistance and processability.The results showed that the octyltriethoxysilanol was successfully synthesized with the yield of about 93.1%and the hydroxyl content about 6.36%;the thermal decomposition temperature of the product can reach about 370℃,and the char yield is 29%at 800℃.To vinyltriethoxysilanol:the yield of about 91%and the hydroxyl content about 7.02%;the thermal decomposition temperature of the product can reach about 375℃,and the char yield is 31%at 800℃.To polytitanosiloxane:the yield of about 84%,the thermal decomposition temperature of the product can reach about 448℃,and the char yield is 39%at 800℃.The thermal decomposition temperature of polytitanium(vinyloctyl)siloxane increases to about 468℃,and the char yield is 44%at 800℃.The polymer has better heat resistance due to the introduction of Ti into the silanol system,much higher than silanol.Comparing the thermal properties of polytitanosiloxane with polytitanium(vinyloctyl)siloxane,the thermal decomposition temperature of the polymer can be increased by 20℃,the char yield at 800℃can be increased by 5%,and the fluidity is excellently(132 Pa·s,50℃).