发泡工艺对超临界CO2／PP微孔发泡泡孔形态的影响

研究了超临界CO2／PP微孔发泡过程中发泡温度和饱和压力对结晶性聚合物PP泡孔形态的影响。结果表明，温度对泡孔形态影响很大，温度升高，熔体黏度和表面张力降低，泡孔变大，泡孔密度减小。与发泡温度相比，CO2饱和压力对泡孔结构的影响较小。压力太低，CO2的溶解度小，泡孔壁太厚，泡孔分布不均匀。随着压力升高，CO2的溶解度增加，熔体黏度减小，所以泡孔直径和泡孔密度都增加，泡孔壁变薄。

Effect of Foaming Parameter on Cell Morphology in Microcellular Foaming of Supercritical CO2/PP

The effects of foaming temperature and saturation pressure on the cell morphology of foamed semicrystalline PP in microcellular foaming of supercriticai CO2/PP were investigated. The experimental results showed the foaming temperature had great effect on the cell morphology; the melt viscosity and surface tension reduced with the elevated temperature that caused the increase in cell size and decrease in cell density; the saturation pressure had less effect on the cellular structure in contrast to the foaming temperature; too low saturation pressure induced too low CO2 solubility, which led to large cell wall thickness and non-uniform cell size distribution; the CO2 solubility increased and melt viscosity decreased as the saturation pressure of supercriticai CO2 enhanced, as a resuit, both the cell size and cell density increased and the cell wall thickness decreased.