Development of an Internal Structure by Amorphous Polymer in the Melt State

For an amorphous polymer, it is well known that annealing under the glass transition temperature introduces changes in physical properties due to entropy relaxation. For casting solutions of amorphous polymers under the glass transition temperature, the molding and solidification history is reflected in their viscoelastic properties (especially tan delta). However, above the glass transition temperature, it has been thought that the conformation of the polymer becomes random. In this study, we evaluated the dependence of the mechanical properties on the duration of melt compression molding by using amorphous polystyrene virgin pellets. From the results, we found that the tensile mechanical properties of virgin PS improved with increases in both the molding duration and temperature. In addition, a new diffraction peak appeared at a low scattering angle in X-ray diffraction measurement.