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Organic-inorganic hybrids based on poly(methyl methacrylate) and polysilsesquioxanes

New organic-inorganic hybrids based on poly(methyl methacrylate), PMMA, and polysilsesquioxane structures (polyhedral oligomeric silsesquioxane, POSS, and/or ladder like structures) were prepared by in situ bulk polymerization. The inorganic phase was generated from 3-glycidyloxypropyltrimethoxysilane, GLYMO, via sol-gel chemistry. Poly(oxypropylene)diamine was used as an epoxy opening agent, as basic catalyst for GLYMO condensation and as PMMA crosslinking agent. Chemical reactions in the systems of different methyl methacrylate , MMA/GLYMO molar ratio were studied by Fourier transform infrared analysis. The high degree of conversion of methoxysilyl groups to -Si-O-Si- linkages was confirmed by 29Si NMR. Hybrid morphology was studied by scanning electron microscopy, SEM. Hybrid with cca. 3 wt % of inorganic phase (calculated as SiO1, 5) showed a discrete microstructure while hybrids with higher amount of inorganic phase (cca. 5 and 7 wt. %) showed characteristic interpenetrating polymer networks, IPN, morphology. Inorganic phase formed as a result of GLYMO hydrolysis and condensation in the sol-gel process influences the glass transition temperature of PMMA. The hybrids have much better thermal stability than PMMA and showed excellent solvent resistance.

poly(methyl methacrylate) ; silsesquioxane ; sol-gel

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