微孔聚碳酸酯的制备工艺与泡孔结构研究

Preparation and Cell Structure of Microcellular Polycarbonate

使用超临界CO2流体作为发泡剂在不同条件下制得一系列微孔聚碳酸酯(PC)。通过扫描电子显微镜观察分析了各种制备工艺参数对微孔PC泡孔结构和分布的影响。结果表明,饱和阶段的时间超过3.5 h时,试样中的CO2基本达到饱和;饱和阶段压力的增加会使泡孔直径减小,泡孔密度增大;而发泡温度的增加和发泡时间的延长则会使泡孔直径增大,泡孔密度减小。当完全发泡时,试样的泡孔结构在厚度方向上有明显区别:试样表皮部分未发泡,有致密的表皮结构;试样表层附近泡孔直径较小,泡孔密度较大;试样中心处的泡孔直径较大,泡孔密度较小。

A series of microcellular polycarbonate foam were prepared using supercritical CO2 as the foaming agent under different preparation conditions.The effects of process parameters on the cell structure and cell distribution were analyzed with the graphs observed by scanning electron microscopy.The results show that CO2 is almost saturated in the specimen when the time of saturation stage is more than 3.5 h.With the pressure of saturation stage increasing, the cell diameter is reduced and the cell density is increased.Differently, when the foaming temperature or the foaming time increases, the cell diameter is increased and the cell density is reduced.The completely foamed specimen has a significant difference of the cell structure in the thickness direction.The scarfskin of the specimen is unfoamed with dense epidermal structure, and the surface layers of the specimen have larger cell diameter and smaller cell density than the central layer.