The Influence Of Cage Structure On Chain Characteristics And Properties Of POSS/PU Hybrid Composite: A Molecular Simulation Approach

Different concentration of Octa-propylglycidyl ether poss(Ope POSS) was incorporated into PU backbones by molecular mechanics and molecular dynamics methods to elucidate the effect of cage structure on chain characteristics and properties of POSS/PU hybrid composites with the software Material Studio 5.5. In combination with the macroscopic properties of relevant experiment, the feasibility and effectiveness of the simulation method was validated. Furthermore, Trisilanolphenyl POSS(TSP – POSS) was incorporated into PU backbones in polymer builder method with different concentrations, respectively. The aggregation and mobility of polymer chains were characterized by Radial distribution function(RDF) and Mean square displacement(MSD) ananlysis. Meanwhile, amorphous cell modulus was applied in construction in TSP-POSS/PU systems in physical blending to compare the different mechanism of properties improvement in chemical bonding. The validation of simulation method and the analysis of structure-property relationship in two different method was attempted to provide the guidline for experimental modification for PU composites.1.The molecular simulation on Ope POSS/PU and simulation method validationDifferent quality percentage OpePOSS/PU polymer structure model was constructed by polymer builder modulus,The MSD、g(r) and Tg of each system were obtained after series steps of energy optimization. The result shows that Ope POSS as an anchor point in the polymer backbone has the dominate effect on chain characteristics of hybrid composites. Increasing as Ope POSS content in the system, the mobility of polymer chain increases Meanwhile, the probability to find another particles at the same distance with Ope POSS is decreased which indicates that the average distance of the adjacent polymer chain is increased. Furthermore, it is coincide to the experiment literature results that the glass transition temperature increases as the Ope POSS loading raising which also validate the reasonable models and the simulation methods.2. The molecular simulation on TSP-POSS modified polyurethane covalently.With polymer builder modulus, different weight percentage of TSP-POSS modified polyurethane was constructed to investigate the relationship between the structure and properties. Results show that when TSP- POSS percentage up to 12.11 wt %, fractures of TSP-POSS have the tendency to self-assemble which apparently reduce the MSD and depart the neighboring chains. Thus, glass transtion temerature is increased as the TSP-POSS concentration rasing.3. The molecular simulation on TSP-POSS modified polyurethane with physical blendingDifferent quality percentage TSP-POSS/PU physical blending system was consturcted to predicate the properties and compare the results to that in chemical method. Results show that in physical blending, TSP- POSS cannot be evenly dispersed into polyurethane. Only the loading less than 3.06 wt %, the TSP-POSS/PU can be in homogeneous phase and the glass transition temperature can be increased to some extent.