注塑工艺参数对HDPE化学发泡行为的影响

Effect of Injection Processing Parameter on HDPE Foaming Behavior

设计了注塑工艺参数对高密度聚乙烯(HDPE)化学发泡质量影响的正交实验,用SEM对发泡HDPE材料样品的泡孔形态和尺寸进行了观察和测量统计,系统研究了注塑温度、注塑压力、注塑速度和冷却固化时间对化学发泡法制备高密度聚乙烯(HDPE)发泡材料泡孔平均直径、泡孔尺寸分布、泡孔密度的影响。结果表明,注塑温度对发泡HDPE的结构参数影响最大,其次为注塑压力。注塑温度的影响与其对发泡剂分解速度、产气量、熔体强度的影响而导致泡孔的形核和长大(并泡)过程有关。通过优化工艺,获得了泡孔平均直径为21μm、泡孔密度为每立方厘米3.2×107个、泡孔尺寸分布均匀的HDPE发泡材料样品。

The effect of injection process parameters on the quality of chemical foaming of high density polyethylene （HDPE） was studied through designing of experiments （DOE） matrices. These samples were then subjected to be observed and statistic by scanning electron microscope （SEM） and Image-Pro software. The effect of injection temperatures,injection pressure,injection speeds,and cooling time on cell size,cell density,and cell size distribution of chemical foaming prepared foamed HDPE materials was researched systematically. The result shows that the injection temperature has the most important affect on foamed HDPE structural parameters,which leads to different decompose rate,amount of gas of foaming agent,melt-viscosity of HDPE,followed by injection pressure. A statistical design analysis was used to identify the optimal process conditions that would result in desirable cell size,cell density and cell size distribution,for example,the highest grade microcells HDPE have been observed at the injection temperatures,injection pressure,injection speeds,and cooling time of 170 ℃,90MPa,12.1 （g/s） and 25 s.