Mechanical properties and morphology of organic silicon/polyurethane IPNs prepared by sol-gel method

Complex coupling agents system with two kinds of functional, crosslinked groups(-NH₂ and -C=C-) are employed for the first time to generate crosslinked structures in the formation of inorganic-organic interpenetrating polymer networks(IPNs) composed of methyl methacrylate-co-maleic anhydride copolymer and silica polymer formed by hydrolysis of tetraethoxysilane via radical polymerization and sol-gel method of two networks. The polymerization process, morphology and the mechanical properties of hybrids are studied by FTIR, TEM, transparency, TG-DTA and stress-strain curve detection. The results indicate that the component ratio has effect to the transparent and mechanical properties of hybrids. The FT-IR detection results proved the formation of crosslink structures between two networks. The TEM observation results indicate that the introduction of covalent bond can control the phase separation of hybrid within 20nm and thus obtain hybrids with higher transparency(above 85%). The mechanical property detection results show that thermal resistance, elastic modulus and tensile strength are all improved by the interpenetration of inorganic phase into hybrid compared with pure organic components.