相对分子质量分布对双峰聚乙烯薄膜树脂性能的影响

Effect of Molecular Weight Distribution on Properties of Bimodal Polyethylene Resin for Films

通过差示扫描量热仪、高温凝胶渗透色谱仪、旋转流变仪表征了2种具有不同力学性能的双峰高密度聚乙烯薄膜树脂(FHM 9455F 1-A、FHM 9455F 1-B)结构的差异性,FHM 9455F 1-A比FHM 9455F 1-B具有更高的冲击强度和拉伸强度。结果表明,FHM 9455F1-A高相对分子质量部分的相对含量更大,片晶间能够形成更多的系带分子,改善了材料的冲击强度,而片晶厚度,特别是厚片晶部分的片晶厚度更厚,使得材料具有更高的拉伸强度。

In this work,the structural difference of two types of bimodal high density polyethylene resins(FHM 9455F 1-A and FHM 9455F 1-B)with different mechanical properties used for films was investigated by means of differential scanning calorimeter,high temperature gel permeation chromatograph and rotational rheometer.The FHM 9455F 1-A resin exhibited higher impact strength and tensile strength than the FHM 9455F 1-B one.The results indicated that the FHM 9455F 1-A resin had a higher relative content in the higher molecular weight fraction,which resulted in the formation of more tie molecules between the lamellas.This result improved the impact strength of PE resins.In addition,the lamella thickness,especially for the thicker lamella contributed to higher tensile strength for the PE resins.