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

Polyhedral oligomeric silsesquioxane (POSS) was a novel compounds with structure of nano-scale organic-inorganic hybrid, which was consisted of three-dimensional Si-O-Si short-chain, and organic substituents inorganic framework, due to its symmetrical cage-like structure, it was easy to design the molecules. According to the vertices of different organic substituents, the POSS could be introduced to the different system to improved the thermal properties, mechanical properties, mechanical strength, flame retardant, anti-oxidation, anti-aging properties of polymers. Therefore, to develop a new type of POSS and POSS-based polymer nano-hybrid materials have an important academic significance and practical value.Octa(y-chloropropyl) polyhedral oligomeric silsesquioxane (POSS) was synthesized through the hydrolysis and condensation reaction. The relationship of reaction conditions and yiled were discussed. In addition, POSS/PMMA was prepared successfully, the characterized and the thermal properties of the sample were studied. The main content of this dissertation is as follows.1. With hydrochloric acid as catalyst, Octa(γ-chloropropyl) polyhedral oligomeric silsesquioxane(POSS) was synthesized through the hydrolysis and condensation ofγ-chloropropyl trimethoxysilane as raw material, methanol as solvent. The effects of reaction time, reaction temperature, feeding ratio and sequene on the yield were investigated, then optimum conditions were obtained and showed to be n(γ-chloropropyl trimethoxysilane):n(hydrochloric acid):n(methanol) 20:15:400, the whole process lasts 15 days, the temperature was kept at 40℃, The maximum yield was 37%.2. The structures and properties of octa(γ-chloropropyl) polyhedral oligomeric silsesquioxane (POSS) were characterized by Fourier transform infrared (FTIR), X-ray diffraction (XRD), Nuclear magnetic resonance (1HNMR, SiNMR) and Gel permeation chromatography(GPC). The results show that:Octa(y-chloropropyl) polyhedral oligomeric silsesquioxane(POSS) with high purity and a symmetrical cage structure were synthesized.3.3. POSS/PMMA complex were synthesized through the atom transfer radical polymerization(ATRP) method with octa(y-chloropropyl) polyhedral oligomeric silsesquioxane(POSS) as the initiator. The effects of the initiator, reaction time, reaction temperature on the yield were investigated. The sample was characterized by means of Fourier transform infrared (FTIR), X-ray diffraction (XRD), Nuclear magnetic resonance 1HNMR), Gel permeation chromatography (GPC)and (DSC, TGA). The results show that:POSS/PMMA complex were synthesized, compared to the pure PMMA, the glass transition temperature (Tg) of POSS/PMMA contenting 5% and 10% POSS increased 12.8℃and 22.6℃respectively. While the decomposition temperature (Td) of the comspites increased 24.4℃and 40.1℃separately. Figure [24] table [7] references [66]...