高电压技术2017，Vol.43Issue(11)：3634-3644,11.DOI:10.13336/j.1003-6520.hve.20171031019
等规和嵌段聚丙烯的结构和性能
Structure and Properties of Isotactic Polypropylene and Ethylene-propylene Copolymer
摘要
Abstract
Polypropylene (PP) is well-known for its excellent electrical and thermal properties,as well as good recycling performance,so it has the potential to replace the cross-linked polyethylene (XLPE) as the cable insulation material in the future.Two kinds of PP such as isotactic homo-propylene (iPP) and ethylene-propylene copolymer (EPC) are selected to study the microstructure,impact strength,and electrical properties.The results show that,there is only α spherulite in iPP and EPC,the spherulites of EPC are smaller and denser than iPP and spherulites of EPC have no distinct interface.The growth rate of the spherulites in EPC is slower than that of iPP,but the crystallization rate is faster.In the different crystallization process,the degree of crystallinity of EPC is lower but the melting point of EPC is higher than that of iPP.The ethylene copolymer molecular chain fragment of EPC can be formed into rubber (EPR) structure,which enhances the EPC impact strength,and temperature of the low temperature brittleness of EPC is-57.3 ℃,which is much lower than iPP-5 ℃.It is found that,at room temperature,the DC breakdown and volume resistivity of iPP are higher than those of EPC.However,with the increasing temperature,the breakdown strength and volume resistivity of EPC become more stable.At 90 ℃,the DC breakdown strengths ofiPP and EPC drop by 27％ and 21％,and the volume resistivities ofiPP and EPC drop by 128.8× 1015 Ω·cm and 52.5× 1015 Ω·cm,respectively.The space charge density of iPP is about three times of EPC,so EPC is more suitable for extrusion insulation material of HVDC cables.The improvements of EPC properties are influenced by the phase structure and spherulite structure.关键词
直流电缆/等规聚丙烯/嵌段共聚聚丙烯/力学冲击强度/空间电荷/直流击穿特性Key words
DC cable/isotactic polypropylene/ethylene-propylene copolymer/mechanical impact strength/space charge/DC breakdown characteristics引用本文复制引用
张伟,徐曼,陈光辉,侯帅,傅明利,李维康..等规和嵌段聚丙烯的结构和性能[J].高电压技术,2017,43(11):3634-3644,11.基金项目
国家重点研发计划(2016YFB0900702) （2016YFB0900702）
南方电网公司科技项目(SGTRC[2014]K1409B06).Project supported by National Key Research and Development Plan(2016YFB0900702),Science and Technology Project of China Southern Grid (SGTRC[2014]K1409B06). （SGTRC[2014]K1409B06）
