Studying the influence of short chain branch (SCB) on the crystal properties and breakdown strength of low-density polyethylene (LDPE) plays an important role in improving the electrical and mechanical properties of LDPE by adjusting the molecular structure. In this work, the SCB and long chain branch (LCB) content of LDPE are quantitatively characterized. Grain size, crystallinity and breakdown strength of LDPE (including AC and DC) are calculated through related characterization experiments. The results show that the SCB content in LDPE is dozens of times that of LCB. Reducing the SCB content can reduce the grain size of 110 face in LDPE and improve the AC and DC breakdown strength. The trap distribution characteristics measured by the thermally stimulated depolarization current (TSDC) method show that the SCB inhibits the formation of deep cavity defects in the LDPE interface area and decreases the trap energy level of crystal defects. This inspired us to improve the breakdown strength by reducing the SCB content in LDPE.

中文翻译：

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短支链对低密度聚乙烯晶体特性和断裂强度的影响

研究短支链（SCB）对低密度聚乙烯（LDPE）晶体性能和击穿强度的影响，通过调节分子结构，对提高LDPE的电性能和机械性能具有重要作用。在这项工作中，定量表征了 LDPE 的 SCB 和长支链 (LCB) 含量。LDPE（包括AC和DC）的晶粒尺寸、结晶度和击穿强度通过相关表征实验计算。结果表明，LDPE中SCB的含量是LCB的几十倍。降低SCB含量可以减小LDPE中110面的晶粒尺寸，提高交直流击穿强度。热激去极化电流（TSDC）法测得的陷阱分布特性表明，SCB抑制了低密度聚乙烯界面区深腔缺陷的形成，降低了晶体缺陷的陷阱能级。这启发我们通过降低 LDPE 中的 SCB 含量来提高击穿强度。