Cyclic Tetravinylsiloxanetetraols as Hybrid Inorganic-Organic Thiol-ene Networks

In this work, organic-inorganic hybrid materials containing stable silanol functionalities were designed by incorporating cyclic tetravinylsiloxanetetraols into photopolymerized polymer networks via the thiol-ene reaction, with the intent of tailoring the thermal and mechanical properties of the resulting materials. The effects of the cyclic tetravinylsiloxanetetraols concentration on the thermomechanical properties and thermal stability of pentaerythritol triallyl ether/pentaerythritol tetra(3-mercaptopropionate) (APE-PETMP) and allyl isocyanurate/pentaerythritol tetra(3-mercaptopropionate) (TTT-PETMP) ternary networks were evaluated using dynamic thermomechanical analysis and thermogravimetric analysis, respectively. Photopolymerization kinetics were monitored using real-time FTIR. Interestingly, an increase in glass transition temperature was observed with the APE-PETMP networks while a decrease in glass transition temperature was observed for the TTT-PETMP networks with increasing concentration of [Vi(OH)SiO]4. These observations are discussed in terms of cross-link density and monomer rigidity.