Shape and Property Change by Mixing Methods of Binary Mixtures of Cross-linked Polystyrene and Liquid Polybutadiene

Abstract

Binary mixture materials were prepared by mixing cross-linked polystyrene and liquid polybutadiene by several methods and their shapes and thermal phase transition behaviors were examined. Evaporating dichloromethane of crosslinked polystyrene and polybutadiene (1/1 wt/wt) solution in dichloromethane at 40 ℃ under reduced pressure gave solid/liquid two-phase-separated materials. Differential scanning calorimetry (DSC) of the materials showed that they had two glass transition temperature (T_g)s, one was T_g(-91.0 ℃) attributed to polybutadiene and the other was T_g (103.1 ℃) attributed to polystyrene. They coincided well with those of original polybutadiene and cross-linked polystyrene, respectively. On the other hand, freeze-drying of the cross-linked polystyrene and polybutadiene (1/1 wt/wt) solution in 1,4-dioxane gave powdered solid materials. DSC analysis of these materials revealed higher temperature shift of polybutadiene T_g (-88.8 ℃) along with lower temperature shift of polystyrene T_g (97.8 ℃). These observations indicated that binary materials with quite different shapes and properties can be prepared by varying the mixing methods.