The influence of electron-beam irradiation on polypropylene (PP) and high-density polyethylene (HDPE) was investigated with a focus on crystallization. A high-temperature (200°C) creep test revealed that the HDPE gradually increased cross-linking density in the range 30–120 kGy, while the PP underwent a chain scission which was quantitatively evaluated by gel permeation chromatography. The mechanical properties were measured in the range -150 to 200°C by a dynamic mechanical analysis. A small presence of C=C and C=O bonds was found in the irradiated PP by a Fourier transform infrared spectroscopy. Crystallization kinetics measured by differential scanning calorimetry and hot-stage optical microscopy results were influenced tremendously by irradiation for HDPE and to a lesser extent for PP. Irradiation caused a decrease in both the number of nucleation centres and the growth rate of individual spherulites. Crystallization was analysed in detail with the help of Hoffman–Lauritzen, Avrami and Arrhenius equations. Interestingly an increasing β-crystal formation with an increasing irradiation level was discovered for PP by X-ray diffraction. A generation of defects in the crystalline structure owing to irradiation was discussed.

研究了电子束辐照对聚丙烯 (PP) 和高密度聚乙烯 (HDPE) 的影响，重点是结晶。高温（200°C）蠕变测试表明，HDPE 的交联密度在 30-120 kGy 范围内逐渐增加，而 PP 发生断链，通过凝胶渗透色谱法定量评估。通过动态机械分析在-150 至200°C 范围内测量机械性能。通过傅里叶变换红外光谱法发现，经辐照的 PP 中存在少量 C=C 和 C=O 键。通过差示扫描量热法和热台光学显微镜测量的结晶动力学结果受到辐射对 HDPE 的影响极大，对 PP 的影响较小。辐照导致成核中心的数量和单个球晶的生长速率下降。借助 Hoffman-Lauritzen、Avrami 和 Arrhenius 方程对结晶进行了详细分析。有趣的是，通过 X 射线衍射发现，PP 的β晶体形成随着辐照水平的增加而增加。讨论了由于辐照而导致晶体结构中缺陷的产生。