The β-crystal nucleating agent ( TMB-5 ) was used to modify recycled polypropylene ( RPP ). The crystallization behavior, melting chara cateristic, crystalline morphology and impact strength of modified RPP were characterized by virtue of DSC, XRD, POM and impact testing apparatus. The results indicated that TMB-5 had strongβ-nucleating ability for RPP crystallization to increase the crystallization temperature of RPP. Meanwhile, modified RPP mainly formed β-spherulites, which increased the impact strength of RPP. However, the impact strength of RPP reduced with increasing mass fraction of β-crystal nucleating agent, which implied that there existed a certain dosage of β-crystal nucleating agent.%采用β-成核剂TMB-5改性回收聚丙烯( RPP)，借助差示扫描量热仪、广角X射线衍射仪、偏光显微镜和摆锤冲击测试仪研究了改性RPP的结晶行为、熔融特性、结晶形态以及冲击强度。结果表明， TMB-5对RPP结晶具有强的β-成核作用，可显著提高RPP的结晶温度。同时诱导RPP形成大量β-晶型，从而提高RPP冲击强度。但随着β-成核剂用量的增加，试样的β-晶型含量和冲击强度均下降，说明β-成核剂用量存在临界值。
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