冲击强度是聚丙烯树脂一项重要的性能指标，采用悬臂梁形式测定聚丙烯树脂冲击强度前，测试样条需经注塑成型并制V形切口。实验采用两种不同熔体流动速率的无规共聚聚丙烯树脂，通过调整注射机的注塑条件及切口机对样条开口的切口强度，探究注塑条件及开口深度、切口弧度及切口根部曲率半径对两种无规共聚聚丙烯悬臂梁冲击强度的影响，以期为正确评定塑料材质的冲击强度提供依据。结果表明：降低聚丙烯的熔融温度、降低注射速度及注射压力、减少保压时间可提升无规共聚聚丙烯的悬臂梁冲击强度。采用不同的开口机对注塑后的样条进行开口，对样条冲击强度大小影响很大，且两种聚丙烯树脂的冲击强度变化趋势相同。切口深度较浅、根部曲率半径越大、切口角度越大，切口处应力和应变越集中，无规共聚聚丙烯的悬臂梁冲击强度越大。

The impact strength of polypropylene resin is an important property index. Before using a cantilever beam to measure the impact strength of polypropylene resin, the test spline needs to be injection molded and V-shaped incision made. The article uses two different melting indexes of random copolymer polypropylene resin. By adjusting the injection molding conditions and the notch strength of the spline opening by incision machine, The effects of injection molding conditions and opening depth, incision radian and curvature radius of incision root on the Izod impact strength of two kinds of random copolymer polypropylene were investigated in order to provide a basis for correctly evaluating the impact strength of plastic materials. The results show that the Izod impact strength of random copolymer polypropylene can be improved by reducing the melting temperature of polypropylene, reducing the injection speed and injection pressure, and reducing the holding time. Different opening machines are used to open the injection molded spline, which has a great influence on the impact strength of the spline, and the impact strength of the two polypropylene resins has the same change trend. The shallower the notch depth, the larger the radius of the root curvature, the larger the notch angle, the more concentrated the stress and strain at the notch, and the greater the Izod impact strength of the random copolymer polypropylene.