Control of thermal and mechanical properties by double-cyclopolymerization and copolymerization of trifunctional POSS with varying organic substituents

Abstract

Abstract Phenyl- and trifluoropropyl-substituted corner-opening type cage silsesquioxane (CO-POSS) monomers capped with methacrylethoxypropyldimethylsiloxy groups at the three silanol moieties were prepared by the hydrosilylation of trisdimethylsilyl-capped heptaphenyl- and heptatrifluoropropyl-substituted trisilanols with ethylene glycol monoallyl ether and subsequent reaction with methacryloyl chloride. Reversible addition-fragmentation chain transferpolymerization was performed on these monomers, and their structures and properties were compared to those of their previously-reported isobutyl-substituted counterparts. The polymer with a phenyl group exhibited enhanced thermal and mechanical properties, whereas the polymer with a trifluoropropyl group exhibited not only water repellency but also oil repellency. In addition, trifunctional CO-POSS monomers with different organic substituents could be used for double-cyclocopolymerization, and tuning of their properties was achieved. Furthermore, the trifunctional CO-POSS monomer could be used for double-cyclocopolymerization with methyl methacrylate without cross-linking.