摘要
电介质聚丙烯薄膜是干式直流电容器的核心,是新能源发电和柔性直流输电的“心脏”,直接影响电能变换的质量与安全。聚丙烯薄膜的晶体结构对电容器的性能起着决定性的作用。本文对三种聚丙烯(PP)粒料经流延双轴拉伸制备成的电容器用电介质薄膜(BOPP)的晶体结构采用广角X-射线衍射、傅里叶变换红外光谱、差示量热扫描等表征法进行了研究。表征结果发现,三种BOPP电介质薄膜均由α相构成,但其结晶度、熔点以及不同晶面方向上的晶粒尺寸存在较大差别。其中,基于北欧粒料的电介质薄膜熔点最低(169℃),结晶度最高(59.8%),且在[060]方向上的晶粒尺寸最大。红外光谱结果表明,基于北欧粒料的BOPP试样中,序列长度为n=14的31螺旋链段最多。通过对BOPP薄膜熔融重结晶后试样的研究发现,三种粒料的结晶度几乎无差别(~53%),但北欧PP粒料的非等温结晶温度最高(119℃),且在熔融过程出现明显β相熔融峰。中石化PP粒料的非等温结晶温度最低,较北欧PP粒料低3℃。
The dielectric polypropylene film is not only the core of dry DC capacitor,but also the“key”of new energy power generation and flexible DC transmission,which directly influences both quality and safety of electric energy conversion.The crystal structure of polypropylene film plays decisive role in the perfor-mance of capacitor.In this paper,the crystal structure of the dielectric film of capacitor(BOPP),which is made of three kinds of polypropylene pellets by way of casting bi-axially drawing,is studied by such charac-terization method as wide-angle X-ray diffraction,Fourier transform infrared spectroscopy and differential scanning calorimetry.It is found by the characterization result that three kinds of BOPP dielectric films are predominantly composed ofα-crystal structures.However,there are notable differences among the films in terms of their crystallinity,melting temperature and the crystallite size in various orientations.The melting point of dielectric film based on Borealis grains is minimum(169℃),the degree of crystallinity is highest(59.8%)and the crystals size along the[060]direction is maximum.The result of infrared spectrum shows that in BOPP species based on Borealis grains the 31 helical chain segments with sequence lengths n=14 is maximum.It is found by the study of specimens after melting recrystallization of BOPP film that the crysta-linity of three kinds of grains is almost identical(about 53%).However,the non-isothermal crystallization temperature of Borealis PP grains is highest(119℃)and obvious aβ-phase melting peak is occurred dur-ing the melting period.In comparison,non-isothermal crystallization temperature of Sinopec PP grains is the lowest,which is 3℃less than that of the Borealis grains.
作者
孙朦
龙厚尹
柏潇
闫寿科
孙晓丽
SUN Meng;LONG Houyin;BAI Xiao;YAN Shouke;SUN Xiaoi(State Key Laboratory of Chemical Resource Engineering,Beijing University of Chemical Technology,Beijing 100029,China;Key Laboratory of Rubber-plastics,Ministry of Education,Qingdao University of Science&Technology,Shandong Qingdao 266042,China)
出处
《电力电容器与无功补偿》
2024年第1期56-62,共7页
Power Capacitor & Reactive Power Compensation
基金
国家重点研发计划(2021YFB2401502)。
关键词
聚丙烯
电介质薄膜
结晶
结构
熔融
polypropylene
dielectric film
crystallization
structure
melting
