振动力场作用下温度对超临界CO_2/PS微孔塑料气泡形态的影响

Effects of Temperature on Cell Morphology of Supercritical CO_2/PS Microcellular Plastics under Vibration Force Field

以超临界CO2 为发泡剂 ,用自行研制的动态发泡模拟机将机械振动力场引入到PS微孔塑料成型过程中 ,初步研究了振动力场作用下温度对微孔塑料气泡形态的影响。实验发现 ,发泡温度越高 ,气泡核长大的速度越快 ,导致气泡合并甚至破裂。但发泡温度过低时 ,超临界CO2 在PS熔体中的扩散速率较低 ,最终制品的泡孔密度小 ,气泡分布也不均匀。在微孔塑料成型过程中施加振动 ,有利于发泡剂在熔体中的分散和混合 ,从而在较低的温度 ( 13 0℃ )下制备出泡孔直径为 18μm、泡孔密度为 7× 10 7个 /cm3

The effect of temperature on the cell morphology of microcellular plastics was analyzed elementarily, in which mechanical vibration was imposing on the molding process of PS microcellular plastics by dynamic foam process simulation machine and supercritical carbon dioxide was used as foaming agent. The results showed that the higher the temperature, the more quickly the nucleus grew, resulted in cell coalescent and breaking. However, the dispersion speed of supercritical carbon dioxide in PS melt was low at lower temperature. So the cell density of final produce was small and cell distribution was not homogeneous. The imposition of vibration on the molding process of microcellular plastics was of benefit to the dispersion and blending of blow agent in the melt. Then the microcellular plastics with cell diameter of 18 μm and cell density of 7×10 7 cells/cm 3 could be prepared at low temperature of 130℃.