The Degradation Behavior of PC/PBT Blends Under Alkaline Solution

摘要

Degradation behavior of PC/PBT blends has been investigated under alkaline condition over a full range of blend ratios. The SEM observation showed PC/PBT blends were incompatible blends with continuous PBT phase and dispersed PC phase. The degradation behavior of PC/ PBT blends was evaluated by change of weight, degradation depth, flexural strength etc. The PC/PBT blends were progressively degraded by cutting of ester linkages in PC and results in decrease of specimen thickness. The weight loss and degradation depth increased linearly with immersion time. It appeared clearly that the corrosion rate of the blends was decreased with increasing PBT fraction. Neat PBT resin showed good resistance to alkaline aqueous solution even at high alkaline concentration. However, more important and interesting thing was that continuous PBT phase in blends was degraded. So that we were discussed that PC phase was degraded and then PBT phase neighbored with the PC phase was also degraded. The degradation was limited only at the surface of specimen, and remained material showed no change of molecular weight and also IR spectrum correspond to virgin blends.