利用升温淋洗分级技术对两种乙丙抗冲共聚物（简称试样1和试样2）进行了分级，并研究了试样及其各级分的化学组成、序列分布、结晶熔融行为和相态结构。结果表明：试样1和试样2均由乙丙无规共聚物、乙丙嵌段共聚物和丙烯均聚物组成；试样2的乙烯含量和乙丙无规共聚物含量均高于试样1，可结晶乙丙嵌段共聚物的共聚单体分布更均匀；试样2的100℃以上高温可溶级分总含量和结晶度均高于试样1；试样2中分散相——乙丙无规共聚物颗粒数更多，颗粒粒径分布较均匀；试样2表现出更好的刚韧平衡性。%Preparative temperature rising elution fractionation is applied to the physical fractionation of two impact ethylene-propylene copolymers(sample1&sample2). The chemical structure,crystallization and melting behavior, phase morphology,and sequence distribution of both samples and their fractions are further observed. The results show that both samples are composed of ethylene-propylene random copolymer, ethylene-propylene block copolymer andpropylene homopolymer. The content of ethylene and ethylene-propylene random copolymer in sample2 is more than that of sample1, and comonomer of ethylene-propylene block copolymer in sample2 is better distributed. Sample2 contains more fractions which can be soluble above100 ℃ thansample 1, and the fractions insample2 eluted above100℃ have higher crystallinity than those insample1. The particles of ethylene-propylene random copolymer in dispersed phase in sample2 are more than in sample1, and homogeneously dispersed. As a result, the sample2 exhibits better rigidity-toughness balance.
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