Thermal induced structural change investigations in PVC/PEMA polymer blend

The optical morphology of fresh and annealed PVC, PEMA and their polyblend revealed that the structure of annealed PVC had changed to become a rod-like structure, whereas the tiny round-shaped domains had developed to a larger size in annealed PEMA. FTIR study showed that there are significant changes in the band positions and band intensities in the spectra due to the annealing effect. X-ray pattern revealed that the crystallinity of the annealed PVC had been increased. TSDC was investigated in the vicinity of the glass transition temperature of PVC, PEMA, and their polyblend at different annealing conditions. The global TSDC spectra of annealed PVC showed two TSDC peaks. Only a very intense peak associated with the alpha -relaxation was observed around the glass transition temperature, whereas an additional peak was observed in the lower temperature side at T=331 K. This peak was examined and could be attributed to sub-T-g relaxation due to the formation of a new structure. On the other hand, global TSDC of PEMA showed a broad alpha -relaxation peak with very low activation energy. (C) 2001 Elsevier Science Ltd. All rights reserved.