THE EFFECT OF NON-EQUILIBRIUM ANNEALING ON THE SWELLING BEHAVIOR OF POLYSTYRENE AND STYRENE-ACRYLONITRILE COPOLYMER

The relaxation behavior of polystyrene (PS) and styrene-acrylonitrile copolymer (SAN) with annealing at temperatures below Tg (non-equilibrium annealing) was studied as a function of the excess enthalpy which was calculated from the absorption of thermal energy as measured by DSC. And also, the non-equilibrium annealing effect on the swelling behavior of PS and SAN with ethanol was investigated. The rate of enthalpy relaxation of SAN with annealing below Tg was equal to that of PS at the same Tg-Ta. It was turned out that the rate of relaxation was hardly affected by the presence of 38mole% of acrylonitrile. It was expected that the mechanisms of enthalpy relaxation process of PS and SAN were identical. The swelling test with ethanol was carried out for the original and annealed samples at 40°C. It became clear that the swelling process of polymeric glasses were affected with annealing below Tg. The non-equilibrium annealing delayed the beginning of swelling. However, the diffusion rate of ethanol was affected slightly with annealing after the beginning of swelling. The swelling process of PS was affected with annealing more than SAN.