Abstract
The method of molecular dynamics simulation is applied to the study of glass transition, local motion of chain molecules, and local structure in amorphous polymers. The glass transition temperature, determined from the change in the thermal expansion coefficient, exhibits the expected dependency on the chain length. The local chain dynamics is investigated by evaluating the time correlation functions of bond reorientation motion and the distribution of resulting reorientation angles. The degree of success of the simulation for atactic polystyrene was examined by comparing the calculated X-ray intensity curve and neutron diffraction curves with experimental data. The calculated curves agree well. The results of the simulation were analyzed in detail to evaluate the intramolecular and intermolecular correlations. The most prominent feature in the intermolecular correlation is the strong tendency for the phenyl groups to have a separation distance of about 6Å.
