Synthesis and characterization of a mercaptopropyl polyhedral oligomeric silsesquioxane(POSS)

(3-Mercaptopropyl)trimethoxysilane has been hydrolyzed and condensed in methanol solution.The results showed that a mixture of cage,random and trapezoidal silsesquioxane structures was synthesized in the presence of a hydrochloric acid catalyst.Mercaptopropyl polyhedral oligomeric silsesquioxane(POSS) was obtained in the presence of the alkaline catalysts Me4NOH or(C6H5CH2)Me3NOH,and the yields were 46% and 64%,respectively.The products were characterized by FT-IR,13C-NMR,29Si-NMR,XRD and DSC. POSS had excellent thermal performance with a high melting point of 352 ℃ and decomposition temperature of 530 ℃.