微发泡注塑聚丙烯复合材料的性能及微观结构

Performance and Microstructure of Polypropylene Composites for Microcellular Foaming Injection

针对常规聚丙烯复合材料应用于微发泡注塑过程中遇到的孔径大、分布不均匀、力学性能损失严重等问题,从基料特性、填充体尺寸、成核助剂等不同角度对材料配方进行优化升级。结果表明:适当提高熔体的加工流动性有利于气泡扩散,材料的拉伸、弯曲强度保持率同比可提升10%~20%;而加入小尺寸填料及成核助剂则可以有效降低泡孔孔径,材料的缺口冲击强度可从8~10 kJ/m^2提升至15~20 kJ/m^2;扫描电镜SEM分析显示,材料的泡孔平均孔径从170~180μm降低至80~90μm,孔密度明显增加。

This study focuses on the defects such as large aperture, uneven distribution and serious losson the mechanical properties, when the normal polypropylene composites using on the microcellular foa-ming injection. The results based on the adjustments on polymer matrix, filler size and nucleating agentshowed that the tensile and flexural strength for the PP composites is improved by 10% ~ 20% becauseof the certain promotion of processing fluidity, while the introduction of small-size filler and nucleatingagent can also elevate the notched impact strength from 8 ~ 10 kJ / m2to 15 ~ 20 kJ / m2due to the reduceon the cell structure. By the used of SEM analysis, it can be confirmed that the average size of foamcell has been shorten from 170 ~ 180 μm to 80 ~ 90 μm, and the density of cell structure is also in-creased remarkably.