结晶特性对聚丙烯空间电荷及直流击穿强度影响  

Effect of Crystalline Characteristics on Space Charge and DC Breakdown Strength of Polypropylene

作　　者：赵洪[1] 吕洪雷 杨佳明[1] 高铭泽 王理想 何辉[1] Hong Zhao;Honglei Lu;Jiaming Yang;Mingze Gao;Lixiang Wang;Hui He(Key Lab of Engineering Dielectrics and Application,Ministry of Education,Harbin University of Science and Technology,Harbin 150080,China)

机构地区：[1]工程电介质及其应用教育部重点实验室(哈尔滨理工大学)

出　　处：《高分子材料科学与工程》2019年第7期88-93,共6页Polymer Materials Science & Engineering

基　　金：国家自然科学基金资助项目(51337002);黑龙江省普通本科高等学校青年创新人才培养计划(UNPYSCT-2016162)

摘　　要：采用扫描电子显微镜、偏光显微镜和差示扫描量热法观察了不同成形条件聚丙烯(PP)的结晶形态及结晶度,通过动态力学热分析(DMA)测试了不同结晶形态PP的力学特性,利用电声脉冲法(PEA)测得不同结晶形态PP的空间电荷特性,并对不同结晶形态PP进行了直流击穿强度测试。结果表明,PP在较高的熔融温度和结晶温度下减少了晶核数目并促进了球晶生长。DMA和PEA测试表明,小球晶可使PP的储存模量降低,大球晶在生长过程中,将较多的杂质和低分子物排挤到无定形区中,导致β松弛损耗增大,从而使室温下的空间电荷量明显增加。直流击穿强度测试表明,当PP形成大且疏的球晶时,击穿过程可沿更短的路径发展,并且无定形区存在较多杂质及低分子物,从而使击穿强度明显降低。The crystalline morphology and crystallinity of PP under different forming conditions were observed by SEM,polarized light microscopy(PLM)and differential scanning calorimetry(DSC).The mechanical properties of different crystalline forms of PP were tested by dynamic mechanical analysis(DMA).The space charge characteristics of different crystal forms of PP were measured by electroacoustic pulse method(PEA),and DC breakdown strength tests were performed on different crystalline forms of PP.The results show that the crystalline morphology and crystallinity of PP are significantly different at different melting temperatures and crystallization temperatures.The higher melting temperature and crystallization temperature decrease the number of nuclei and promote the growth of spherulites.The results of DMA and PEA tests show that the small spherulites can reduce the storage modulus of PP.During the growth process of large spherulites,more structural defects are pushed out into the amorphous region,resulting in the increasedβ-relaxation loss and thus the space charge at room temperature increases significantly.The DC breakdown strength test results show that when PP forms large and sparse spherulites,the breakdown process can develop along a shorter path,and there are more impurity in the amorphous areas,so that the breakdown strength is significantly reduced.

关 键 词：聚丙烯 结晶温度 结晶形态 空间电荷 直流击穿强度 

分 类 号：TQ325.14[化学工程—合成树脂塑料工业]