For highly impact polypropylene (HIPP), a good balance between stiffness and toughness has attracted much attention from both industrial and academic research. Herein, two HIPP resins (A and B) with different ethylene contents and impact resistances especially at low temperatures are investigated. Their chain microstructure is studied by combining preparative temperature rising elution fractionation (P-TREF) with multiple characterization techniques such as high-temperature gel permeation chromatography (HT-GPC), Fourier transform infrared (FTIR) spectroscopy, ¹³C nuclear magnetic resonance (¹³C NMR), wide-angle X-ray diffraction (WAXD), differential scanning calorimetry (DSC), rheometer, and thermal fractionation. Both samples are mainly composed of four portions: amorphous ethylene−propylene random copolymer (EPR), ethylene−propylene (EP) segmented and blocky copolymer, and isotactic polypropylene homopolymer. Sample A contains ∼30 wt% EPR fractions eluted at 35 °C, ∼9 wt% EP segmented and blocky copolymers eluted at 80–100 °C, and ∼19 wt% highly isotactic polypropylene fractions eluted at 125–140 °C, which are higher than the contents of corresponding fractions in sample B. Moreover, most fractions of sample A have higher molecular weights than the corresponding fractions of sample B. The contribution of different components to stiffness and toughness is also discussed. The excellent impact resistance of sample A is demonstrated from the perspective of chain microstructure.

对于高抗冲聚丙烯（HIPP），刚度和韧性之间的良好平衡已经引起了工业和学术研究的广泛关注。本文中，研究了两种乙烯含量和抗冲击性不同的HIPP树脂（A和B），尤其是在低温下。通过将制备温度升高的洗脱分级分离（P-TREF）与多种表征技术（例如高温凝胶渗透色谱（HT-GPC），傅里叶变换红外光谱（FTIR）光谱，¹³ C核磁共振（^13）NMR），广角X射线衍射（WAXD），差示扫描量热法（DSC），流变仪和热分馏。两种样品均主要由四部分组成：非晶态乙烯-丙烯无规共聚物（EPR），乙烯-丙烯（EP）嵌段和嵌段共聚物以及全同立构聚丙烯均聚物。样品A包含约35 wt％的EPR馏分，在35°C下洗脱；约9 wt％的EP嵌段和嵌段共聚物，在80–100°C下洗脱，以及约19 wt％的高等规聚丙烯馏分，在125–140°C下洗脱，样品A中的大多数组分具有比样品B中相应的组分更高的分子量。此外，还讨论了不同组分对刚度和韧性的影响。