GLASS-TRANSITION OF ATACTIC POLYSTYRENE WITH LESS CHAIN ENTANGLEMENTS

Atactic polystyrene was dissolved and refluxed in benzene keeping the polymer concentration well below the critical concentration C value f or chain overlap. After rapid freezing of the solution by injecting it directly into liquid nitrogen, the solvent was sublimated so that the expanded chain coils with few entanglements could be obtained. T-g fo r this material was found to be 11 K lower than the normal polystyrene even after annealing up to 470 K. Comparison of the infrared spectra shows some conformational differences between the freeze-dried and the normal PS. Upon shock-cooling and subsequent freeze- drying, all vibr ational bands appear much sharper, indicating an increase in structure regularity.