加工助剂对高压电缆半导电屏蔽料性能影响研究

Effect of Processing AIDS on Performance of Semi-conductive Shielding Materials for High Voltage Cable

高压电缆半导电屏蔽料主要由基体树脂、导电炭黑和加工助剂通过熔融混合加工而成。其中,加工助剂是影响高压电缆半导电屏蔽料品质的重要因素,然而加工助剂对高压电缆半导电屏蔽料性能的影响鲜有报道。该文采用熔融共混法制备导电炭黑(CB)/乙烯–丙烯酸丁酯共聚物(EBA)半导电屏蔽料,系统研究导电炭黑用量、分散剂类型与含量、交联剂类型与用量对半导电屏蔽料结构与性能的影响。采用扫描电子扫描显微镜和光学显微镜观察CB/EBA半导电屏蔽料内部微观结构和表面光洁度,通过电阻率测试仪和电子万能试验机评价CB/EBA半导电屏蔽料电性能和力学性能。实验结果表明:在导电炭黑质量分数为30%、分散剂N.N’-乙撑双硬脂酰胺为2.0%及交联剂双叔丁基过氧异丙基苯在1.0%时达到最优性能,半导电屏蔽料23℃和90℃电阻率为13.6Ω·cm和307.9Ω·cm,拉伸强度和断裂伸长率分别为18.5MPa和241.5%,且试样表面没有直径大于50μm的突起点,能够满足高压电缆屏的应用要求。此外,对比分析发现,我国自主研制的高压电缆半导电屏蔽料与国外同类产品拥有同等性能水平。该文工作为高压电缆半导电屏蔽料国产化提供了理论依据和数据支撑,对推动高压电缆半导电屏蔽料自主可控生产具有重要意义。

Semi-conductive shielding materials for high voltage cable are made of matrix resins,conductive carbon black and processing aids through melting blending technology.The processing aids play an important role in the quality of semi-conductive shielding materials.However,the effect of processing aids on the performance of semi-conductive shielding materials is rarely reported.Herein,conductive carbon black(CB)/ethylene-butyl acrylate copolymer(EBA)semi-conductive shielding material is prepared to investigate the effects of processing aids.Scanning electron microscope and optical microscope is used to observe the inner microstructure and surface finish of the CB/EBA materials.The electrical and mechanical properties of the CB/EBA materials are performed on a resistivity tester and an electronic universal testing machine.The semi-conductive shielding materials exhibited an electrical resistivity of 13.6/307.9Ω·cm at 23/90℃,a tensile strength of 18.5 MPa and an elongation at break of 241.5%,respectively,at 30%CB,2.0%EBS and 1.0%cross-linking agent,respectively.No obvious protrusion point of larger than 50μm is observed on the surface of the samples,achieving the requirements of high-voltage cable in practical applications.The prepared semi-conductive shielding materials in this work show the same level with the foreign products,which is of significance in promoting the development of domestic high-voltage cable shielding materials.