Basin-type insulators are made by epoxy resin composite materials. Curing defects are easily formed in basin-type insulators, and degrade their insulating performances. High curing exothermic rates of epoxy resin composite materials have deemed as the main cause of curing defects formation. In this study, methyl tetrahydrophthalic anhydride (Me-THPA) was used to extend the molecular chain of liquid epoxy resin to prepare epoxy resin composite materials with low curing exothermic rates. Curing exothermic properties, molecular weight distribution, curing stress, microstructures, and surface flashover characteristics of the composite materials were investigated. The results showed that chain-extended epoxy resin had low curing exothermic rates. The curing stress of the chain-extended epoxy resin composite materials was small. The curing defects forming in the composite materials were inhibited. Negative DC surface flashover characteristics of these composite materials were improved. Furthermore, variation of functional groups of the composite materials was studied before and after surface flashover tests. Results showed that the content of carbon–oxygen single bonds (–C–O) in the chain-extended epoxy resin composite materials was observed to decrease. The –C–O bonds also affect the voltage withstand capability of the epoxy resin composite materials.

盆形绝缘子由环氧树脂复合材料制成。固化缺陷容易在盆形绝缘子中形成，并降低其绝缘性能。环氧树脂复合材料的高固化放热速率被认为是固化缺陷形成的主要原因。在这项研究中，使用甲基四氢邻苯二甲酸酐（Me-THPA）来扩展液态环氧树脂的分子链，从而制备出具有低固化放热速率的环氧树脂复合材料。研究了复合材料的固化放热性能，分子量分布，固化应力，微观结构和表面闪络特性。结果表明，扩链环氧树脂固化放热速率低。扩链环氧树脂复合材料的固化应力小。复合材料中形成的固化缺陷得到抑制。这些复合材料的负直流表面闪络特性得到改善。此外，在表面闪络测试之前和之后，研究了复合材料的官能团的变化。结果表明，扩链的环氧树脂复合材料中碳氧单键（–C–O）的含量降低。–C–O键还会影响环氧树脂复合材料的耐电压能力。结果表明，扩链的环氧树脂复合材料中碳氧单键（–C–O）的含量降低。–C–O键还会影响环氧树脂复合材料的耐电压能力。结果表明，扩链的环氧树脂复合材料中碳氧单键（–C–O）的含量降低。–C–O键还会影响环氧树脂复合材料的耐电压能力。