Microcellular injection molding of polypropylene and glass fiber composites with supercritical nitrogen
Microcellular injection molding of polypropylene and glass fiber composites with supercritical nitrogen
复制标题
超临界氮气微孔注射成型聚丙烯和玻璃纤维复合材料
DOI：
10.1177/0021955x14528931
复制
发表时间：
2014-09-01
影响因子：
2.5
通讯作者：
Zhao, Ling
中科院分区：
文献类型：
--
作者：
Xi, Zhenhao;Sha, Xinyi;Zhao, Ling
采用超临界氮气作为物理发泡剂，对聚丙烯/玻璃纤维复合材料（PP-1684/GF-950）进行了微孔注射成型。通过实验矩阵设计，系统研究了玻璃纤维含量和操作条件对模压试样泡孔结构、玻璃纤维取向和力学性能的影响。结果表明，冷却和剪切作用对发泡制品的泡孔形态和玻璃纤维取向有一定的影响。当w GF / w PP = 11时，通过改善玻璃纤维的泡孔形态、分散状态和取向，可有效提高发泡聚丙烯-玻璃纤维复合材料的力学性能。百分之八通过对成型样品力学性能的信噪比分析，得到最佳注射成型工艺条件为：注射量36 mm，超临界氮气质量分数0.4%，注射速度60%，熔体温度190℃，模具温度70℃。在这些最佳条件下生产的聚丙烯-玻璃纤维复合材料的模塑样品表现出非常均匀的纤维分散和平均泡孔尺寸小于30 µm的微孔结构。微孔材料的力学性能（以质量比计）显著提高，尤其是冲击强度。
Microcellular injection molding of polypropylene and glass fiber composites (PP-1684/GF-950) was performed using supercritical nitrogen as the physical blowing agent. Based on design of experiment matrices, the influences of glass fiber content and operating conditions on cell structure, glass fiber orientation and mechanical properties of molded samples were studied systematically. The results showed the cell morphology and glass fiber orientation of foaming parts were definitely influenced by the cooling and shear effects. The mechanical properties of foamed polypropylene–glass fiber composites could be effectively enhanced by improving the cell morphology, dispersion state and orientation of the glass fiber at optimal weight percentage w GF / w PP = 11 . 8 % . And the optimal conditions for injection molding were obtained by analyzing the signal-to-noise ratio analysis of the mechanical properties of the molded samples, which were a shot size of 36 mm, a supercritical N2 weight percentage of 0.4%, an injection speed of 60%, a melt temperature of 190℃ and a mold temperature of 70℃. The molded specimens of polypropylene–glass fiber composites, produced under those optimal conditions, exhibited very uniform fiber dispersion and microcellular structures with an average cell size less than 30 µm. And the mechanical properties normalized by weight ratio of the microcellular samples were increased significantly, especially the impact strength.