摘要
通过核磁共振波谱仪、凝胶渗透色谱仪、差示扫描量热仪、扫描电子显微镜等对乙烯-1-丁烯共聚物为橡胶相的抗冲共聚聚丙烯的结构进行了分析,并测试了其模塑收缩率及耐应力发白性能。结果表明:乙烯-1-丁烯共聚物可溶物的相对分子质量较低时,所制抗冲共聚聚丙烯在注塑过程中易受到剪切应力作用而沿熔体流动方向形成柱状取向结构,此橡胶相取向结构赋予抗冲共聚聚丙烯低模塑收缩率和良好的耐应力发白性能;乙烯-1-丁烯共聚物可溶物的相对分子质量较高时,所制抗冲共聚聚丙烯在注塑过程中则呈现典型的"海-岛"状橡胶形态,因而表现出较高的模塑收缩率和较差的耐应力发白性能。
The structure of impact polypropylene(IPP) with ethylene/1-butenen copolymer(EBC) as rubber phase were analyzed by nuclear magnetic resonance spectrometer,gel permeation chromatograph,differential scanning calorimeter,and scanning electron microscope. The mold shrinkage and stress whitening properties of the copolymer were measured. The results show that when the molecular weight of EBC soluble is low,the IPP prepared is under the action of shear stress during the injection molding process and forms a columnar oriented structure in the melt flow direction. This rubber phase oriented structure favors to low mold shrinkage and good stress whitening resistance to IPP. When the molecular weight of EBC soluble is high enough,the IPP prepared exhibits a typical island-like rubber phase during the injection molding process,representing higher mold shrinkage and poor resistance to stress whitening.
引文
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