不同配比聚丙烯和双峰聚乙烯复合体系的力学性能和介电性能  

Mechanical and Dielectric Properties with Different Mass Ratio of PP and BPE

作　　者：操卫康 徐欣 CAO Weikang;XU Xin(Suzhou Power Supply Company,State Grid Jiangsu Electric Power Co.,Ltd.,Suzhou 215004,China)

机构地区：[1]国网江苏省电力有限公司苏州供电分公司,苏州215004

出　　处：《电线电缆》2024年第4期7-13,共7页Wire & Cable

摘　　要：为研究节能环保型中低压非交联电缆绝缘材料,采用熔融共混的方式制备了不同配比的聚丙烯(PP)和双峰聚乙烯(BPE)复合体系,观察微观结构,测定其力学性能和介电性能,研究PP和BPE的最佳配比。通过带热台的偏光显微镜观察单一PP和30%PP/70%BPE(质量分数)复合体系的等温结晶,可以看到140℃时PP球晶的生长,以及30%PP/70%BPE复合体系下致密的结晶结构,说明混料均匀性良好。通过测定不同配比PP/BPE复合体系的力学冲击性能,发现脆韧转变点出现在30%PP/70%BPE的试样中。力学拉伸试验表明,在10 mm·min^(-1)的拉伸速率下,弹性模量、拉伸强度、断裂伸长率和断裂能均随PP质量分数的增加而增加。介电性能测试表明,30%PP/70%BPE复合体系的体积电阻率在10^(14)数量级,相对介电常数在2.0~2.3之间,介质损耗因数在10^(-4)数量级,复合体系的介质损耗因数相较于单一PP和单一BPE略有增加,其整体电气性能符合中低压电缆绝缘材料的要求。In order to research energy-saving and environmently friendly non-crosslinked materials for medium and low voltage cable insulation,polypropylene(PP)and bimodal polyethylene(BPE)composite system with different mass ratio were prepared by melting blend method.Microstructures were observed,mechanical and dielectric properties were also measured to find out the best mass ratio of PP and BPE.Through hot stage polarized microscope,isothermal crystallization of pure PP and 30%PP and 70%BPE(mass fraction)composite system was observed.Growth of PP spherulites at 140℃and dense crystal structure of 30%PP and 70%BPE composite system were observed,which showed good uniformity of the mixture.In mechanical impact properties measurement of different compsite systems,brittle-ductile transition point occured in 30%PP and 70%BPE composite system.Tensile tests showed that under the stretching speed of 10 mm·min^(-1),elastic modulus,tensile strength,tensile elongation at break and fracture energy increased with the rise of PP content.In dielectric properties test of 30%PP and 70%BPE composite system,polymer volume resistivity was basically in the order of 10^(14),dielectric constant maintained between 2 and 2.3,and dielectric loss factor was in the order of 10^(-4).Besides,a little increase in dielectric loss factor appeared in PP and BPE composites compared to pure PP and pure BPE,electrical performance of which could meet requirements of insulation material for low and medium voltage cables very well.

关 键 词：聚丙烯 双峰聚乙烯 熔融共混 力学性能 介电性能 

分 类 号：TM211[一般工业技术—材料科学与工程] TQ325[电气工程—电工理论与新技术]