电缆绝缘用聚丙烯/弹性体复合材料的高温介电性能  

High Temperature Dielectric Properties of Polypropylene and Elastomer Blends for Cable Insulation

作　　者：蒋毅恺 徐曼[1] 王若霏 徐静 路文贤 Jiang Yikai;Xu Man;Wang Ruofei;Xu Jing;Lu Wenxian(State Key Laboratory of Electrical Insulation and Power Equipment,Xi’an Jiaotong University,Xi’an 710049,China;Far East Cable Co.Ltd,Wuxi 214000,China)

机构地区：[1]电力设备电气绝缘国家重点实验室(西安交通大学),西安710049 [2]远东电缆有限公司,无锡214000

出　　处：《电工技术学报》2024年第1期99-109,共11页Transactions of China Electrotechnical Society

摘　　要：为研究弹性体含量对聚丙烯(PP)不同温度下介电性能的影响,制备了不同聚烯烃弹性体(POE)含量的试样,并通过添加β成核剂的方式对聚丙烯晶型进行调控,以优化聚丙烯/弹性体复合体系的高温介电性能。试验结果表明,相较于POE体系,POE/成核剂体系的柔韧性和高温力学的稳定性提高,高温交流击穿强度也明显改善,90℃时,POE40-β的交流击穿强度比POE40高11.4%。此外,β成核剂的引入抑制了POE体系高温低频下相对介电常数的上升现象,并大大降低了高温下的损耗,90℃时,工频下的介质损耗因数从10^(-2)降到10^(-3),下降了一个数量级。研究结果表明,β成核剂的添加不仅可以改善聚丙烯/弹性体复合体系的力学性能和高温击穿强度,还提高了聚丙烯和弹性体的相容性,削弱了界面极化的作用,使其表现出更为优异的介电性能。Polypropylene(PP),which has excellent electrical properties,is a research hotspot of potential recyclable cable insulation materials at present.Nevertheless,PP is not capable as cable insulation material because of its stiffness and brittleness.Further modification should be studied for cable insulation applications.Elastomers are often used to improve the mechanical properties of PP.Because of the large difference in melting point between PP and elastomer,the enhanced relaxation of segments at high temperatures results in a significant deterioration of electrical properties.Therefore,β-nucleating agent was used to regulate the crystal morphology of PP in order to optimize the high temperature dielectric properties of polypropylene and elastomer blends.Firstly,blends were prepared with and without nucleating agent in micro twin-screw extruder,for polyolefin elastomer(POE)contents of 20%,40%and 60%in weight.In the case of blends nucleated with TMB-5,the PP was previously melt blended with the additive at 0.06 weight fraction of and subsequently blended with the elastomer.The changes in microstructure of specimens were tested through wide-angle X-ray diffraction(WAXD)and differential scanning calorimetry(DSC).The morphologies of the crystals were observed by scanning electron microscope(SEM).The structure and molecular motion information of the specimen were reflected by the dynamic mechanical thermal analysis.The mechanical and electrical properties were all investigated,with emphasis on the dielectric properties at different temperatures.The results show that,for samples incorporatingβ-nucleating agent,β-crystals appear and ethylene crystals disappear.The introduction ofβ-crystals significantly improves the tensile strength while retaining the toughening effect of POE.The tensile strength of POE40-βis 46.4%higher than POE40.Compared with the POE system,the high-temperature mechanical stability of the POE/nucleating agent system is improved,and the high-temperature AC breakdown strength also increases signifi

关 键 词：聚丙烯 弹性体增韧 晶型调控 介电性能 

分 类 号：TM215[一般工业技术—材料科学与工程]