文章摘要
iPP/PET原位微纤复合材料的超临界二氧化碳发泡行为
Isotactic Polypropylene/Polyethylene Terephthalate in Situ Microfibrillar Composites Foams Using Supercritical CO2
  
DOI:10.16865/j.cnki.1000-7555.2018.07.012
中文关键词: 发泡  原位微纤  超临界二氧化碳
英文关键词: foaming  in situ microfibrils  supercritical CO2
基金项目:国家自然科学基金资助项目(21664004);黔科合基础[2017]1090
作者单位
韦良强1,黄安荣1,孙 静1,董珈豪1,罗珊珊1,宁德阳2 1.国家复合改性聚合物材料工程技术研究中心,贵州 贵阳 550014
2.四川大学 制造科学与工程学院,四川 成都 610065 
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中文摘要:
      利用微纳层叠共挤技术中独特的剪切拉伸复合流动场作用实现聚对苯二甲酸乙二醇酯(PET)在聚丙烯(iPP)中的原位微纤化,研究了PET的原位微纤化对iPP/PET复合材料发泡行为的影响。扫描电子显微镜结果显示,经过微纳层叠共挤装置挤出后,PET在iPP中形成直径为0.2~1μm 的微纤。PET微纤化显著地改善了iPP的结晶性能、流变性能及发泡性能。差示扫描量热测试结果表明,PET微纤对iPP具有明显的异相成核作用,能提高iPP的结晶温度和熔点;拉伸流变行为分析发现,PET微纤的形成使得iPP产生明显的应变硬化现象;通过超临界二氧化碳发泡发现,iPP/PET原位微纤复合材料的泡孔比纯iPP更加稳定,尺寸更小,密度更大,且泡孔内存在三维微纤网络结构。
英文摘要:
      The isotactic polypropylene (iPP)/ polyethylene terephthalate (PET) in situ microfibrillar composites were prepared by micro-nano-stack co-extrusion technique based on its strong shear-elongational mixed flow field, and its effect on the foaming behavior of iPP was studied. The scanning electron micrographs illustrate that the micro-nano-stack co-extrusion process elongates the dispersed PET phase in the iPP matrix into high-aspect-ratio microfibrils with the diameter of 0.2~1 μm. The formation of PET microfibrils greatly affect the crystalline behaviors, rheological and foaming properties of iPP. The differential scanning calorimetry results reveal that the heterogeneous nucleation sites provided by the PET microfibrils enhance the crystallization and melting temperature of iPP. Uniaxial extensional viscosity test shows a strain-hardening behavior in the iPP/PET microfibrillar composites, which cannot be observed in the neat iPP. Supercritical CO2 was used to investigate the effect of the PET microfibrils on the foaming behavior of iPP. Results reveal that the presence of PET microfibrils in iPP yields foams that exhibit smaller cell size, larger cell density and entangled microfibrils networks exist in cell.
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