温度和掺杂含量对有机硅弹体/八乙烯基-笼型倍半硅氧烷纳米复合材料绝缘性能的影响  

Effect of Temperature and Filler Content on Insulation Properties of Silicone Elastomer/Octavinyl Polyhedral Oligomeric Silsesquioxane Nanocomposites

作　　者：王启隆 陈向荣 张添胤 王恩哲 任娜 Wang Qilong;Chen Xiangrong;Zhang Tianyin;Wang Enzhe;Ren Na(College of Electrical Engineering Zhejiang University,Hangzhou 310027,China;ZJU-Hangzhou Global Scientific and Technological Innovation Center,Hangzhou 311200,China;Zhejiang Provincial Key Laboratory of Power Semiconductor Materials and Devices ZJU-Hangzhou Global Scientific and Technological Innovation Center,Hangzhou 311200,China;Advanced Electrical International Research Center International Campus Zhejiang University,Haining 314400,China)

机构地区：[1]浙江大学电气工程学院,杭州310027 [2]浙江大学杭州国际科创中心,杭州311200 [3]浙江省宽禁带功率半导体材料与器件重点实验室(浙江大学杭州科创中心),杭州311200 [4]浙江大学先进电气国际研究中心,海宁314400

出　　处：《电工技术学报》2023年第5期1139-1153,共15页Transactions of China Electrotechnical Society

基　　金：国家自然科学基金项目(52007165);浙江省自然科学基金重点项目(LZ22E070001);浙江大学“百人计划”(自然科学A类)资助。

摘　　要：为了研究温度和掺杂含量对有机硅弹体/八乙烯基-笼型倍半硅氧烷(SE/OV-POSS)纳米复合材料绝缘和热学性能的影响,该文制备了纯有机硅弹体及不同掺杂含量的SE/OV-POSS纳米复合材料,对材料进行了SEM断面形貌表征、傅里叶红外光谱测量、热重分析、交联度实验、热刺激去极化电流测试、不同温度下介电谱和直流电导率测量,以及不同电场强度下的量子化学计算,分析了掺杂含量对SE/OV-POSS纳米复合材料交联网络的影响,以及温度对纳米复合材料电荷传输的作用机制。结果表明:掺杂质量分数为3%的OV-POSS可以与有机硅弹体基体形成密集的交联网状结构,有效抑制基体分子长链段发生介电弛豫运动,使纳米复合材料的热分解温度、交联度、α弛豫温度和陷阱能级显著增大;在20℃和120℃下,OV-POSS的未反应乙烯基和无机内核在纳米复合材料中分别起到深电子陷阱和深空穴陷阱作用,阻碍电极注入的载流子在材料内部传输,导致纳米复合材料的直流电导率小于纯有机硅弹体;然而在220℃下,纳米复合材料内部的大量热电子激发导致其绝缘特性的劣化。上述研究结果表明,适量掺杂的OV-POSS可以有效提升有机硅弹体在20℃和120℃下的绝缘性能。The silicon carbide-based wide bandgap(WBG)electronic power modules gradually develop towards a higher current,higher voltage,and miniaturization for realizing higher power density,leading to thermal and electric stress concentration.Therefore,the ideal encapsulation materials need lower permittivity,dielectric loss,electrical conductivity,and high-temperature resistance.The silicone elastomer(SE)is promising to be applied for high-temperature encapsulation in WBG power modules due to its excellent high-temperature resistance and low storage modulus.Polyhedral oligomeric silsesquioxane(POSS)is the known smallest nanofiller,which is widely used in various high-technology areas.Octavinyl polyhedral oligomeric silsesquioxane(OV-POSS)is selected in this paper due to its high reactivity with the SE matrix.This paper investigates the thermal and insulation properties of SE/OV-POSS nanocomposites with different filler contents under 20℃,120℃,and 220℃.Moreover,the effect of the filler content on the crosslinking network of SE/OV-POSS nanocomposites and the mechanism of the temperature on the charge transport of the nanocomposites are analyzed.For the thermal experiments,field emission scanning electron microscopy,Fourier transform infrared spectroscopy,thermal gravity analysis,and crosslinking degree measurements are performed to characterize the nanofiller distribution and analyze chemical groups,thermal stability,and molecular structure of the nanocomposites.For the electrical experiments,the dielectric spectroscopies,thermally stimulated depolarization current,and DC electrical conductivities at different temperatures are measured to analyze the effect of OV-POSS on the molecular chain relaxation process,trap characteristics,and insulation properties of the nanocomposites with different filler contents.Moreover,the quantum chemical calculations of the pure SE and SE/OV-POSS nanocomposite are performed at different electric fields to acquire the variation total density of states,molecular orbit energy level,dipol

关 键 词：有机硅弹体 八乙烯基-笼型倍半硅氧烷(OV-POSS) 纳米复合材料 绝缘性能 温度 

分 类 号：TM211[一般工业技术—材料科学与工程]