【摘要】 以超临界CO2作为物理发泡剂,对低密度聚乙烯(LDPE)进行了微孔发泡的研究。介绍了微孔塑料成型过程中聚合物/气体均相体系的形成、气泡成核和气泡长大及定型这三个步骤。并分析了加工工艺因素(温度、压力)等对制品中泡孔尺寸和密度的影响:泡孔直径随挤出压力的增加而减小;泡孔密度随压力的增加而增加;泡孔直径随压力降速率的增大而减小;泡孔密度随压力降速率的增大而增加;而适当提高温度有利于减小泡孔直径、增加泡孔密度。更多还原

【Abstract】 Extrusion of LDPE microcellular plastics using supercritical carbon dioxide is investigated.Three steps in forming of microcellular plastics namely forming of homogeneous gas/polymer system,nucleation and growing and shaping of gas bubbles are introduced.The influences of processing factors on bubble dimension and bubble density of sample are analyzed:a higher pressure and a higher pressure drop rate and a propriety higher temperature in the die results in smaller cells and greater cell density.更多还原