工艺条件对微孔塑料挤出成型的影响

Effect of Technological Conditions on Microcellular Plastics Extrusion Processing

通过CFD软件对超临界CO2/PS均相熔体在快速降压口模中流动状态的数值模拟,研究了工艺参数对CO2/PS均相熔体气泡成核的影响。研究表明:在CO2溶解度范围以内,增加CO2浓度和增大流率有利于成核更多的气泡,但不利于小尺寸泡孔的生成;在满足发泡温度条件时,降低口模温度有利于高密度小尺寸泡孔的生成;压力降或压力降率越大越有利于形成数量尽可能多、尺寸尽可能小的泡孔。

The influence of technological condition on cell nucleation was studied in mieroeellular plastics extrusion processing for supercritieal CO2/PS by a finite element method CFD. It showed that a higher CO2 concentration or a higher mass flow rates induced a higher nucleation density but a larger cell size. Above the foaming temperature, cell size decreased and cell density increased with a decreasing of the temperature. A larger pressure drop or pressure drop rate was favorable for producing a smaller cell size and a larger cell density.