Study On Preparation And Thermal Properties Of POSS-based Polymeric Materials

A series of polyhedral oligomeric silsesquioxane (POSS)-based hybrids were prepared by the conventional free radical polymerization technique. Their structures were characterized and the relationship between structure and properties were discussed in detail. The main contents of this thesis include the following points:1. The synthesis of POSS monomers, the preparation method of POSS-based hybrids and the relationship between structure and properties were reviewed in detail.2. A series of POSS-based hybrids were prepared by the copolymerization reactions between the octa-vinyl polyhedral oligomeric silsesquioxane monomers and comonomers such as Styrene, Methyl methacrylate, Acetoxystyrene, Hydroxystyrene and Vinylpyrrolidone.3. The POSS-based hybrids were characterized by FTIR, ¹H-NMR, ²⁹Si-NMR and UV. The POSS content in the hybrids were determined using three kinds of different methods and could be effectively controlled by varying the POSS feed ratio.4. It was estimated that about 5⁸ vinyl groups in POSS participated in the copolymerization reactions by the ¹H-NMR spectra. And it was supposed that PS-POSS, PMMA-POSS, PAS-POSS and PHS-POSS polymers mainly formed star-structured materials, while PVP-POSS polymer mainly possessed net-work structure.5. The thermal properties of POSS-based hybrids were characterized by DSC aind TGA. The enhancement mechanisms of their thermal properties were discussed, such as nanoeffect, dipole-dipole interaction, hydrogen bonding interaction and physical aggregation and so on. It was found that star-structure and network-structure POSS-based polymers had superior thermal properties than linear POSS-based polymers.