注塑工艺参数对微发泡PP/SiO2纳米复合材料发泡行为及力学性能的影响

用正交实验研究了喷嘴温度、注射压力、注射速度和冷却时间等工艺参数对化学发泡法制备的微发泡聚丙烯（PP）/SiO2纳米复合材料的泡孔平均直径和泡孔密度的影响，用Image-pro图像处理软件对复合材料的泡孔尺寸进行了观察和统计，并对其力学性能进行分析。结果表明，在PP中添加纳米SiO2后，喷嘴温度对发泡PP/SiO2纳米复合材料的发泡行为影响最大，其次为注射速度；实验范围内较理想的工艺参数为：喷嘴温度175 ℃、注射压力67.5 MPa、注射速度95 %、冷却时间35 s，在此工艺条件下获得了泡孔平均直径为15.71 m、泡孔密度9.8×106个/cm3的PP/纳米SiO2发泡复合材料，冲击强度达5.45 kJ/m2。

Effect of Injection Molding Parameters on the Foaming Behavior and Mechanical Properties of PP/ SiO2 Nanocomposites

The effect of nozzle temperature, pressure, melt viscosity, and cooling time on the cell size, cell density, and mechanical properties of chemically foamed PP/SiO2 nanocomposites were studied through orthogonal experiments. The Image-Pro software was used to count the cell size. It was found that the nozzle temperature was the most important factor, melt viscosity was the second. The optimal injection processing parameters were nozzle temperature 175 ℃, injection pressure 67.5 MPa, melt viscosity 95 %, and cooling time 35 s, by which an impact strength of 5.45 kJ/m2 ,an average cell diameter of 15.71 m , an cell density was 9.8×106 bubble/cm3 were obtained.