An Investigation on Structure and Thermal Properties of TSP-POSS/PU Hybrid Composites by Molecular Simulation Approach

Trisilanolphenyl PUSS (TSP-POSS) with open cage structure was incorporated into PU backbones in concentrations of 0 wt%,3. 06 wt%, 6. 56 wt%, 10. 13 wt%, 12. 11 wt%, 15. 36 wt% and 19.87 wt%, respectively by molecular mechanics and molecular dynamics methods to elucidate the effect of TSP-PUSS on structure and thermal properties of polyurethane hybrid composites. These hybrid composites models were characterized by mean square displacement, radial distribution function, temperature-volume behavior and Xray diffraction at molecular level. The result shows: as TSP-PUSS loading is lower than 12. 11 wt%, the mobility of the polymer chains is enhanced apparently due to the humping open cage structure of TSP-PUSS which increases the average distance between the polymer chains; as TSP-PUSS loading is higher than 12. 11 wt%, TSP-POSS self-reunites and crystalline clusters are formed which lead to restricting the motion of the polymer chains. According to temperature-volume behavior analysis, the introduction of TSP-PUSS can significantly increase the glass transition temperature of polyurethane hybrid composites and thus, the introduction of TSP-PUSS is supposed to improve the hybrid composite' s thermal stability with reasonable concentration in application.