【作者】 刘文辉；

【导师】 肖登明； 李旭光；

【作者基本信息】 上海交通大学 ， 高电压与绝缘技术， 2010， 硕士

【摘要】 s无机纳米/聚合物复合材料在宏观上表现出区别于普通聚合物介质的特殊性能,特别是在光、电、磁和热等方面展示出广阔的应用前景,已成为材料科学中的一个令人关注的研究方向。当前,在电气绝缘领域,多数学者主要以交联聚乙烯与低密度聚乙烯等为基础材料,进行不同浓度及不同种类无机纳米复合材料的各种介电特性的初步研究。但是,从研究的深度和广度方面来讲,对聚合物纳米复合材料的介电性能的研究仅停留在不同种类的添加剂上,对相同种类不同粒径以及含有不同表面处理剂的纳米微粒形成的复合介质的介电性能的研究还少有相关报道。本文采用LDPE作为基料,以亲水性与疏水性两种表面处理剂下的7种不同粒径SiO₂纳米颗粒作为添加剂制备复合介质试样。以电声脉冲法（Pulsed Electro-acoustic Method）进行了复合材料空间电荷分布的测量,研究表明浓度增大后,各粒径对空间电荷的抑制效果较好;进行了交流、直流正极性与负极性击穿试验,并用Weibull分布对试验结果进行了统计分析,试验结果表明不同表面处理对复合介质的击穿场强的影响较大,且亲水性纳米SiO₂/LDPE复合介质的击穿场强普遍比疏水性纳米SiO₂/LDPE复合介质的击穿场强低;采用强场电导测试系统进行了高场下的电导测试,结果表明2wt%浓度下,各试样高场电导率随粒径增大而逐渐增大;最后,以Agilent公司生产的宽频介电谱仪进行了复合材料介电谱的研究,研究表明各试样的介电常数相差不大,其中以7nm/2wt%复合介质的介电常数最小。更多还原

【Abstract】 Inorganic nanocomposite polymer materials shows some unexpected characteristics such as heat、light、electricity、magnetics in macro way compared to common polymers and demonstrates broad application prospects. It has become a concerning research hotspots in material science. At present, many scholars mainly make the cross-linked polyethylene and low-density polyethylene as the basic materials and make various preliminary dielectric property study based on several concentrations of different inorganic nano-composite materials. However, in terms of study depth and breadth, the dielectric properties study of the nanocomposite polymer materials also stay in different additives. The additive of the same types but different size or different surface treatment is rarely reported.This article adopts LDPE as the base material and seven kinds of SiO₂ nano-particles under hydrophilic and hydrophobic surface modification as the additives. The PEA（Pulsed Electro-acoustic Method） was used to measure space charge distribution of nanocomposite polymer materials, the study findings shows that the inhibitory effect of all kinds of particle size on space charge become better when the concentration increases. The AC, positive and negative DC breakdown test were carried out, and Weibull distribution was used to make statistical data analysis on the test results. The experiments results shows that different surface treatment has big impact on the breakdown strength of nanocomposite polymer materials, and the breakdown strength of hydrophilic nano SiO₂/LDPE composite generally smaller than those of hydrophobic nano SiO₂/LDPE. High field conductivity test system was adopted to make high field conductivity tests. The test results shows that under the 2wt% concentration, and the high-field conduction of all samples increase with the particle size increase. At last, 4294A broad band dielectric spectrometer of agilent company was used to make the study of dielectric spectra, the study shows that the difference of dielectric constant is smaller in all samples, and 7nm/2wt% concentration of nanocomposite polymer materials has the smallest dielectric constant.更多还原