多価フェノール共沈化合物添加によるポリカーボネートの熱安定効果

Abstract

The thermal stability and recyclability of polycarbonate resin (PC) composites filled with coprecipitated polyhydric phenol/polyethylene glycol (CGP) have been investigated. The composites were evaluated after 4 repeated molding. For the composites containing 0.02wt% polyhydric phenol CGP, the number-average molecular weight (Mn) of PC in the composites, measured by gel permeation chromatography, decreased from 24300 to 22100 after 4 injection molding cycles while the unfilled PC resin control decreased to 21000. These results suggest that the PC molecule depolymerized during the injection molding process due to the thermal energy and stress. On the other hand, we found that the CGP reduced the increase in PC Izod impact strength to 120% that of the neat PC resin. In addition, we studied the effects of the addition of a coprecipitate of polyhydric phenol with polyethylene glycol at levels of 0.02 to 0.03wt%. The glass transition temperatures (Tg) of the composites were evaluated by dynamic viscoelastometry. Using the Fox equation to examine the Tg-Mn-1 plots of these PC composites, it was observed that these results were different from those expected for particle dispersed PC composites.These findings suggest that the addition of polyhydric phenol/polyethylene glycol coprecipitation compounds in PC improved the stability of PC. This implies that added coprecipitation compounds may be an effective method in the recycle of PC resin.