热拉伸比对PET/ PE 原位微纤化复合材料形态和拉伸性能的影响

采用熔融挤出2热拉伸2淬冷方法制备了聚对苯二甲酸乙二醇酯( PET) / 聚乙烯( PE) 原位微纤化复合材料。固定体系组成( PET/ PE 为15/ 85), 热拉伸比增加, PET 粒子相继从球状转变成椭球状、棒状和纤维状; 除了最小粒径保持基本不变外, 最大和平均粒径均逐渐减小。微纤化复合材料在PE 的加工温度下成型时, 纤维能够良好地保持在体系中, 但在PET 的加工温度下成型时, 纤维重新熔融, 形成球状粒子。复合材料的拉伸模量和拉伸强度随拉伸比增加显著增加, 表明微纤化对材料具有良好的增强效果; 而断裂伸长率随热拉伸比增加剧烈下降, 产生明显的韧-脆转变。比基本断裂功( we ) 先随热拉伸比( HSR) 增加而增加, 热拉伸比为19117 左右时达到最大值, 继续增加热拉伸比, we 降低。 

INFLUENCE OF HOT STRETCH RATIO ON MORPHOLOGY AND TENSILEPROPERTIES OF POLY( ETHYLENE TEREPHTHALATE) ANDPOLYETHYLENE IN-SI TU MICROFIBRILLAR COMPOSITE

The in-situ microfibrillar composite based on poly (ethylene terephthalate) ( PET) and polyethylene( PE) was prepared through melt ext rusion, hot stretching and quenching process. Fixing the mass composition(15 ∶85) of the PET and PE, increasing the hot stretch ratio, the spherical and ellipsoidal PET particles t ransformto rodlike particles, finally to well-defined microfibers. During hot stretching, the maximum and average diametersof PET particles reduced steadily while the minimum fiber diameter remained constant . The PET fibers were successfully preserved in the materials while being processed at the processing temperature of PE, but they were meltedagain and deformed into spherical particles at the processing temperature of PET. The tensile modulus and st rengthof the microfibrillar composites are significantly enhanced with increasing the hot st retching ratio, indicating that themicrofibers have a good reinforcement on the PET/ PE composites. The ultimate elongation is greatly decreased withhigher hot stretching ratio and there is a critical hot st retching ratio, at which the ductile-brittle t ransition occurs.The specific essential work of f racture ( we ) of the composite first increases with the increase of the hot stretch ratio,and shows a maximum at a hot st retch ratio of 19117, then decreases with further increasing the hot st retch ratio.