It is difficult for polymeric materials to avoid the conflict between the mechanical properties and flowability in manufacturing large-sized injection-molded products. To solve the issue, this paper develops an industrial volume-pulsatile injection molding (VPIM) machine to introduce a high-amplitude vibration force field into the entire injection molding process. As a one-step morphology control, the vibration force field can drive the dispersed Poly(ethylene terephthalate) (PET) droplets to form the stiff microfibrils to improve the mechanical properties of the high-density polyethylene (HDPE) with high melt flow index (MFI). HDPE matrix is toughened and reinforced simultaneously under the synergistic effect of VPIM and PET. The impact and yield strengths of the HDPE/PET composite sample prepared by VPIM are increased by 696% and 28.5%, respectively, compared with that of the pure HDPE sample prepared by conventional injection molding (CIM). The optimal process frequency is found to be 0.5Hz for the mechanical properties of HDPE/PET composite. The phase and impact-fractured surface morphologies indicate that the dramatic improvement of the mechanical properties should be attributed to the in-situ formation of PET submicron-fibrils and hybrid shish-kebabs in the intermediate region. The morphological analysis results are verified by DSC, DMA, 2D-WAXD, and 2D-SAXD tests. From a multi-physics perspective, the influencing mechanism of the vibration flow field on the morphology is put forward to reveal why the mechanical properties of HDPE/PET composite are the best at 0.5Hz.

对于聚合物材料而言，在制造大型注塑产品时很难避免机械性能和流动性之间的冲突。为了解决这个问题，本文开发了一种工业体积脉动注射成型（VPIM）机器，以在整个注射成型过程中引入高振幅振动力场。作为一步式形态控制，振动力场可以驱动分散的聚对苯二甲酸乙二酯（PET）液滴形成坚硬的微纤维，从而改善具有高熔体流动指数的高密度聚乙烯（HDPE）的机械性能（ MFI）。HDPE基质在VPIM和PET的协同作用下同时增韧。VPIM制备的HDPE / PET复合材料样品的冲击强度和屈服强度分别提高了696％和28.5％，分别与通过常规注塑（CIM）制备的纯HDPE样品进行了比较。对于HDPE / PET复合材料的机械性能，发现最佳工艺频率为0.5Hz。相和冲击断裂的表面形态表明，机械性能的显着改善应归因于中间区域中的PET亚微米原纤维和杂种烤肉串的原位形成。通过DSC，DMA，2D-WAXD和2D-SAXD测试验证了形态分析结果。从多物理场的角度出发，提出了振动流场对形貌的影响机理，以揭示为什么HDPE / PET复合材料的机械性能在0.5Hz时最佳。对于HDPE / PET复合材料的机械性能，发现最佳工艺频率为0.5Hz。相和冲击断裂的表面形态表明，机械性能的显着改善应归因于在中间区域中原位形成PET亚微米原纤维和杂种烤肉串。通过DSC，DMA，2D-WAXD和2D-SAXD测试验证了形态分析结果。从多物理场的角度出发，提出了振动流场对形貌的影响机理，以揭示为什么HDPE / PET复合材料在0.5Hz时的机械性能最佳。对于HDPE / PET复合材料的机械性能，发现最佳工艺频率为0.5Hz。相和冲击断裂的表面形态表明，机械性能的显着改善应归因于中间区域中的PET亚微米原纤维和杂种烤肉串的原位形成。通过DSC，DMA，2D-WAXD和2D-SAXD测试验证了形态分析结果。从多物理场的角度出发，提出了振动流场对形貌的影响机理，揭示了HDPE / PET复合材料在0.5Hz时机械性能最佳的原因。相和冲击断裂的表面形态表明，机械性能的显着改善应归因于中间区域中的PET亚微米原纤维和杂种烤肉串的原位形成。通过DSC，DMA，2D-WAXD和2D-SAXD测试验证了形态分析结果。从多物理场的角度出发，提出了振动流场对形貌的影响机理，以揭示为什么HDPE / PET复合材料的机械性能在0.5Hz时最佳。相和冲击断裂的表面形态表明，机械性能的显着改善应归因于中间区域中的PET亚微米原纤维和杂种烤肉串的原位形成。通过DSC，DMA，2D-WAXD和2D-SAXD测试验证了形态分析结果。从多物理场的角度出发，提出了振动流场对形貌的影响机理，以揭示为什么HDPE / PET复合材料的机械性能在0.5Hz时最佳。