Correlation between Internal Structure and Time-Temperature Dependence on Bending Properties of PC/ABS Blend Injection Moldings

摘要

This investigation was directed towards the experimental analysis of bending properties of injection molded PC/ABS blend and GFPC/ABS blend. To study the internal structures of injection molded articles, three point bending tests of as-received and shaved skin layer specimens were carried out at various temperatures and strain rates, and time -temperature superposition principle was applied to bending properties. From the results of bending test, two different straight lines of activation energy were obtained when plotting the temperature dependence of time -temperature shift factor. The activation energy varied by the change of specimen thickness in the case of PC/ABS blend. On the other hand, the activation energy exhibited constant value in spite of the change of thickness in the case of GFPC/ABS blend. It can be considered that PC/ABS blend injection molding has heterogeneous internal structure through thickness, whereas GFPC/ABS blend injection molding has uniform internal structure.Furthermore, the morphology of each article was also examined by scanning electron microscopy. It was obvious that PC/ABS blend had heterogeneous phase distribution through thickness direction, whereas GFPC/ABS blend had uniform distribution. Therefore, the activation energy of PC/ABS blend molding varied dramatically by shaving its skin layer.From the above all results, it appears that the internal structures of polymer blend injection moldings can be understood by using the activation energy obtained by time-temperature superposition.