Preparation of novel UV-cured methacrylate hybrid materials with high thermal stability via thiol–ene photopolymerization

Methacryloxypropyl-polyhedral oligomeric silsesquioxane (MAP-POSS) was photopolymerized with the tri- or tetra-functional thiol monomer in different stoichiometry. A novel inorganic–organic methacrylate hybrid material with highly cross-linked network and high performance was synthesized by UV-initiated thiol–ene click chemistry. SEM–EDAX images and XRD diffractograms showed that no agglomeration of MAP-POSS was observed, indicating MAP-POSS dispersed uniformly in the hybrid materials. Real-time FTIR was employed to monitor the conversion of thiol and methacrylate as a function of irradiation time, and the results revealed that highly thiolated monomer could promote the conversion of methacrylate effectively because of stronger chain propagation capability. The TGA indicated that the hybrid materials had high thermal stability of which the onset decomposition temperature rose to 350 °C, approximately 50 °C higher than that of the traditional UV-cured epoxy acrylate/triethylene glycol dimethacrylate (EA/TEGDMA, 70:30 w/w) resin. The highest glass transition temperature (T_g) of the hybrid materials was 76.2 °C. Compared with traditional EA/TEGDMA resins, the novel hybrid materials consisted of MAP-POSS had fast curing rate, high mechanical properties and thermal stability which made the wider practical applications of UV-cured hybrid materials feasible.