PP/PA6共混比例对其水辅助注塑管件性能及微观形态的影响

以聚丙烯 (PP)为基材，聚酰胺6(PA6)为分散相，制备了4种共混比例的PP/PA6复合材料，考察了共混比例对其水辅助注射成型技术（WAIM）管件拉伸强度及微观形态的影响。结果表明，试样拉伸强度随PA6含量增加先减小后增大；近模壁层和近水层的PA6分散相为大长厚比的长条状或长片状，中间层分散相为椭球状，且随PA6含量增加各层分散相有聚集长大的趋势；管件近模壁层和近水层的晶粒小而密且沿流动方向排列，而中间层晶粒相对更粗大；PP只形成了一种晶型，PA6形成了2种晶型；近水层和近模壁层PP结晶度高于中间层；PA6随其含量增加其结晶度有增大的趋势，且近模壁层结晶度较高。

Influence of PP/PA6 Blending Ratio on Performance and Morphology of WAIM Pipes

PP/PA6 blends were prepared at four blending ratios using PP as a continuous phase and PA6 as a disperse phase, and the effect of PP/PA6 blending ratio on the tensile strength and microstructure of the pipes obtained by WAIM with PP/PA6 blends was investigated. The tensile experimental results indicated that the tensile strength of the pipes increased at first and then tended to decrease with an increase of PA6 content. The scanning electron microscopic observation showed that the PA6 phase was dispersed in both the near-wall and the near-water layers in a long strip or long slice shape with a large length/thick ratio, but it was dispersed in the middle layer as ellipsoids. There is an increase trend in the aggregation and growth of the dispersed phases in each layer with an increase of PA6 content. Polarizing microscopic observation showed that some small and dense crystals were formed along the flow direction at the near-wall and near-water layers, whereas the relatively larger crystals were distributed at the middle layer. Moreover, PP was found to only form one crystal form during the WAIM process, but two crystal forms were generated in the PA6 phase. The degree of crystallinity of PP domain at the near-water and near-wall layers was higher than that at the middle layer. The degree of crystallinity of PA6 phase increased with its weight fraction in the blends, while a high degree of crystallinity was maintained for the PA6 phase at the near-wall layer.