Solvent Effect on the Glass Transition Temperature of Syndiotactic Polystyrene Viewed from Time-Resolved Measurements of Infrared Spectra at the Various Temperatures and Its Simulation by Molecular Dynamics Calculation

摘要

Time-resolved infrared spectral measurement was performed in the solvent-induced crystallization process of syndiotactic polystyrene (sPS) glass at the various temperatures,and the crystallization kinetics were analyzed quantitatively.Both of the crystallization rate constant and the crystallinity estimated after passage of long time were found to decrease with decrease in the crystallization temperature.The extrapolation of the rate constant and the crystallinity to the zero values allowed us to estimate the glass transition temperature (T_g) in the organic solvent atmosphere.The Tg of the original glass sample (ca.100 deg C) was found to shift to -90 +- 10 deg C for chloroform,-70 +- 10 deg C for benzene,and -30 +- 10 deg C for toluene.The solvent with higher solubility or higher interaction with sPS was found to shift the T_g at higher degree.To understand this plasticizing effect of solvent from the microscopic point of view,the molecular dynamics calculation was performed for sPS-toluene and sPS-chloroform systems,and a good correspondence was obtained about the T_g shift between the observed and calculated results.