电力电缆用含石墨烯屏蔽材料的研究

发布时间：2018-06-25 13:17

本文选题：交联聚乙烯绝缘电缆 + 屏蔽层　；参考：《华东理工大学》2017年硕士论文

【摘要】：随着我国输配电系统的升级换代,中高压交联聚乙烯绝缘电缆(XLPE电缆)每年的需求量在不断增加。目前XLPE电缆所使用的半导电屏蔽料主要采用在乙烯-醋酸乙烯共聚物(EVA)中加入导电炭黑及其他助剂交联制成,炭黑作为导电填料的添加量一般在15wt～50wt%。但由于添加了大量的炭黑,不但会降低屏蔽料的加工性能与力学性能,同时,屏蔽料的表面也会因此变得粗糙。在电缆的使用过程中,屏蔽层表面的凸起在高压电场下很容易产生针尖效应,引发电树枝现象,最终导致绝缘层被击穿。为了降低屏蔽层中导电填料的添加量,采用电学、力学性能更佳的石墨烯作为导电填料代替部分炭黑。首先,采用溶液法制备了 EVA/CB-GNS复合材料,确定了填料配比为EVA/15%CB-1.5%GNS。该配方虽然电学性能优异,但是力学性能有较大的缺陷。为了进一步提高材料的力学性能,本研究采用熔融混合法进行工艺优化,通过添加润滑剂、交联剂、抗氧剂,采用合适的加工条件来提升复合材料的力学性能。经实验确定15wt%导电炭黑、5wt%石墨烯、3wt%硬脂酰胺、3wt%过氧化二异丙苯(DCP)、0.75wt%抗氧剂300、转速为65转、混合时间为1Omin的加工条件,制得的屏蔽料样品各项指标均达到了行业标准规定,体积电阻率达到97.1Ω·cm,断裂伸长率与拉伸强度分别达到513.7%与 15.5MPa。为了提升石墨烯在复合材料中的分散性能与结合力,首先通过在石墨烯表面接枝KH570对石墨烯进行改性,增强了石墨烯与EVA基体的结合力。然后,采用溶液法,将改性得到的石墨烯(MrGO)用于制备EVA/CB-MrGO复合材料,确定了复合材料的加料配方,并对复合材料性能进行了测试表征。结果表明,MrGO的电学性能虽然较普通石墨烯有所下降,但是它和EVA基体的界面结合力有了极大的提升。制备得到的EVA/10%CB-6%MrGO复合材料的力学性能较EVA/15%CB-1.5%GNS复合材料有了较大提升,EVA/10%CB-6%MrGO复合材料展现了良好的力学性能。其中断裂伸长率与拉伸强度为554.1%与13.8MPa,分别提升了 215.5%与90.1%。
[Abstract]:With the upgrading of transmission and distribution systems in China, the annual demand for XLPE cables is increasing. At present, the semi-conductive shielding material used in XLPE cable is mainly made by adding conductive carbon black and other auxiliaries to ethylene vinyl acetate copolymer (EVA). However, due to the addition of a large amount of carbon black, not only the processing and mechanical properties of the shielding material will be reduced, but also the surface of the shielding material will become rough. During the use of the cable, the protruding of the shield layer surface is easy to produce the pinpoint effect under the high voltage field, which leads to the phenomenon of electric tree and finally leads to the breakdown of the insulating layer. In order to reduce the amount of conductive filler in the shielding layer, graphene, which has better mechanical properties and electrical properties, is used as the conductive filler instead of some carbon black. Firstly, EVA / CB-GNS composites were prepared by solution method, and the ratio of the fillers was determined as EVA / 15-1.5 GNS. Although the formula has excellent electrical properties, its mechanical properties have some defects. In order to further improve the mechanical properties of the composite, the melt mixing method was used to optimize the process. The mechanical properties of the composite were improved by adding lubricant, crosslinking agent, antioxidant and suitable processing conditions. The experimental results show that the processing conditions of 15wt% conductive carbon black, 5wt% graphene, 3wt% stearamide, 3wt% dicumyl peroxide (DCP), 0.75wt% antioxidant, 65rpm, 1Omin, and all the parameters of the samples are up to the industry standard. The volume resistivity reached 97.1 惟 cm, elongation at break and tensile strength reached 513.7% and 15.5 MPA, respectively. In order to improve the dispersibility and adhesion of graphene in composites, the adhesion between graphene and EVA matrix was enhanced by modifying graphene onto the surface of graphene. Then, the modified graphene (MrGO) was used to prepare EVA / CB-MrGO composites by solution method. The addition formula of the composites was determined, and the properties of the composites were tested and characterized. The results show that the electrical properties of Mr go are lower than those of ordinary graphene, but the interfacial adhesion between Mr go and EVA matrix has been greatly improved. Compared with EVA / 15-1.5 GNS composites, the mechanical properties of the prepared EVA / 10-6 / 10 ~ (-6) Mrs go composites are better than that of EVA / 15-1.5 / GNS composites. The mechanical properties of the EVA / 10-6 / 10 ~ (-6) Mrs go composites show good mechanical properties. The elongation at break and tensile strength were 554.1% and 13.8 MPa, which increased by 215.5% and 90.1%, respectively.
【学位授予单位】：华东理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM247

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