The Synthetical Research Of Polyhedral Oligomeric Silsesquioxane (POSS) And POSS/Polymer

Polyhedral oligomeric silsesquioxane (POSS) was a Si-O-Si askeleton structure of inorganic/organic hybrid molecular. According to Si atoms on the POSS substituents connected to different organic substituents, the POSS could be introduced to the different system to improved the mechanical properties, thermal properties, anti-oxidation, flame retardant of polymers.Therefore, it is very significant to prepare functional POSS monomers-and POSS/polymer hybrid materials.In this paper, OvPOSS and Epoxy-POSS were synthesized. The relationship of reaction conditions and yiled were discussed. In addition, the characterized and the thermal properties of the Epoxy-POSS/EP were studied. This thesis achieved some results as follow:1. With acetone as the solvent, OvPOSS was prepared using vinyltrichlorosilane as raw materia through hydrolytic polycondensation of silsesquioxanes. The structures and properties of OvPOSS were characterized by FTIR, XRD,1HNMR,29SiNMR and TGA.The effects of reaction time, amount of water, reaction temperature on the yield were investigated. The optimum conditions were obtained to be V(monomer):V(H2O):V(acetone)=2:7:20, the whole process lasts72h and40℃, The maximum yield was14.0%.2. The Epoxy-POSS was prepared using OvPOSS as raw material by epoxidation reaction. The structures and properties of Epoxy-POSS were characterized by FTIR,1HNMR and29SiNMR. The effects of Concentration of hydrogen peroxide, reaction time,reaction temperature and the number of peracetic acid on the number of epoxy substitutes on OvPOSS was investigated.The result indicated that when V(CH3COOH):V(H2O2)=0.5:1,60℃,12h, the average number of epoxy groups on OvPOSS is4.3. Epoxy-POSS/EP complex were prepared via the polymerization of DGEBA in the presence of Epoxy-POSS. The structures and properties of Epoxy-POSS/EP were characterized by XRD, TGA and DSC. The fine phase—separated structures were obtained in the Epoxy-POSS/EP complex. TGA shows that,5wt%Epoxy-POSS/EP complex compared to the pure EP, Td decreased19.8℃, the residual rate of hybrid materials increased12.2%, thermal stability. DSC shows that,5wt%Epoxy-POSS/EP complex compared to the pure EP, Tg decreased25.6℃.Fig.[24] table [10] references [75]...