Abstract：The solid insulating materials represented by epoxy resin inevitably generate local cracks under long-term electrical/mechanical stress, which seriously affects their service life. In this paper, a novel epoxy insulating composite with one-component UV-photosensitive microcapsules is proposed. When the crack is generated and the microcapsule is broken, the damage channel is filled with the photosensitive healing agent and cured by UV excitation. Meanwhile, nano-SiO2 is introduced into the epoxy matrix as an ultraviolet reflecting agent to protect the healing agent in the microcapsule from the premature polymerization. Properties of microcapsules and composites are tested by optical microscope (OM), scanning electron microscope (SEM), infrared spectrometer, thermogravimetric analyzer and dielectric spectrum analyzer. The results show that the microcapsules are compact and uniform, and have good heat resistance. In addition, the SiO2 composite matrix has significant UV-shielding effect, which ensures the reactivity of the healing agent from the capsule core. And the composite has an excellent effect on the healing of micro-crack damage while maintaining good intrinsic properties of epoxy resin.
[1] 律方成, 詹振宇, 张立国, 等. 等离子体氟化改性微米AlN填料对环氧树脂绝缘性能的影响[J]. 电工技术学报, 2019, 34(16): 3522-3531. Lü Fangcheng, Zhan Zhenyu, Zhang Liguo, et al.Effect of plasma fluorinated modified micro-AlN filler epoxy resin on the insulation properties[J]. Transactions of China Electrotechnical Society, 2019, 34(16): 3522-3531. [2] 谢伟, 杨征, 程显, 等. 环氧树脂材料热氧老化特性研究[J]. 电工技术学报, 2020, 35(20): 4397-4404. Xie Wei, Yang Zheng, Cheng Xian, et al.Study on thermo-oxygen aging characteristics of epoxy resin material[J]. Transactions of China Electrotechnical Society, 2020, 35(20): 4397-4404. [3] Sima Wenxia, He Jiahui, Sun Potao, et al.Novel nanostructure composite dielectric with high insu-lation performance: silica-based nanometer-sized porous composite insulating paper reinforced by ceramic fibers[J]. Scripta Materialia, 2020, 181: 58-61. [4] 迟庆国, 崔爽, 张天栋, 等. 碳化硅晶须/环氧树脂复合介质非线性电导特性研究[J]. 电工技术学报, 2020, 35(20): 4405-4414. Chi Qingguo, Cui Shuang, Zhang Tiandong, et al.Study on nonlinear characteristics on conductivity of silicon carbide whisker/epoxy resin composites[J]. Transactions of China Electrotechnical Society, 2020, 35(20): 4405-4414. [5] 赵玉顺, 何元菡, 杨克荣, 等. Me-THPA扩链改性环氧树脂对其固化物绝缘特性的影响[J]. 电工技术学报, 2020, 35(增刊1): 311-319. Zhao Yushun, He Yuanhan, Yang Kerong, et al.Insulation performance of Me-THPA chain-extended epoxy resin cured products[J]. Transactions of China Electrotechnical Society, 2020, 35(S1): 311-319. [6] 王有元, 刘玉, 王施又, 等. 电热老化对干式变压器中环氧树脂特性的影响[J]. 电工技术学报, 2018, 33(16): 3906-3916. Wang Youyuan, Liu Yu, Wang Shiyou, et al.The effect of electrothermal aging on the properties of epoxy resin in dry-type transformer[J]. Transactions of China Electrotechnical Society, 2018, 33(16): 3906-3916. [7] Liu Shengkai, Zhang Junjie, Shi Baohui, et al.Damage and failure mechanism of 3D carbon fiber/ epoxy braided composites after thermo-oxidative ageing under transverse impact compression[J]. Composites Part B: Engineering, 2019, 161: 677-690. [8] 谢从珍, 袁超, 何子兰, 等. 复合绝缘子典型内部缺陷的相控阵检测[J]. 高电压技术, 2014, 40(3): 837-842. Xie Congzhen, Yuan Chao, He Zilan, et al.Ultrasonic phased array to inspect typical internal defects of composite insulators[J]. High Voltage Engineering, 2014, 40(3): 837-842. [9] Sun Potao, Sima Wenxia, Yang Ming, et al.Accumulative effect of repeated lightning impulses on transformer insulation: mechanism analysis[J]. IEEE Transactions on Dielectrics and Electrical Insulation, 2016, 23(4): 2430-2437. [10] 朱思瑞, 刘洋, 阮羚, 等. 环氧树脂浇注类绝缘管型母线易发缺陷分析及检测手段[J]. 电工技术学报, 2019, 34(12): 2664-2670. Zhu Sirui, Liu Yang, Ruan Ling, et al.The defects in the resin impregnated paper insulated tubular bus-bar and its test method[J]. Transactions of China Electrotechnical Society, 2019, 34(12): 2664-2670. [11] Sun Potao, Sima Wenxia, Jiang Xiongwei, et al.Review of accumulative failure of winding insu-lation subjected to repetitive impulse voltages[J]. IET High Voltage, 2019, 4(1): 1-11. [12] 罗杨, 吴广宁, 刘继午, 等. 局部放电作用对变频电机匝间纳米复合绝缘的损伤机理研究[J]. 电工技术学报, 2014, 29(6): 303-310. Luo Yang, Wu Guangning, Liu Jiwu, et al.Study on PD damage mechanism of nano-composite used as turn insulation in inverter-fed traction motors[J]. Transactions of China Electrotechnical Society, 2014, 29(6): 303-310. [13] Acome E, Mitchell S K, Morrissey T G, et al.Hydraulically amplified self-healing electrostatic actuators with muscle-like performance[J]. Science, 2018, 359(6371): 61-65. [14] Cao Yue, Tan Yujun, Li Si, et al.Self-healing electronic skins for aquatic environments[J]. Nature Electronics, 2019, 2(2): 75-82. [15] Hu Zunxiang, Hu Xiangming, Cheng Weimin, et al.Performance optimization of one-component polyure-thane healing agent for self-healing concrete[J]. Construction and Building Materials, 2018, 179: 151-159. [16] Li Chenghui, Zuo Jinglin.Self-healing polymers based on coordination bonds[J]. Advanced Materials, 2020, 32(27): 1903762. [17] Gao Lei, He Jinliang, Hu Jun, et al.Photoresponsive self-healing polymer composite with photoabsorbing hybrid microcapsules[J]. ACS Applied Materials & Interfaces, 2015, 7(45): 25546-25552. [18] Gao Lei, Yang Yang, Xie Jiaye, et al.Autonomous self-healing of electrical degradation in dielectric polymers using in situ electroluminescence[J]. Matter, 2020, 2(2): 451-463. [19] Lesaint C, Risinggård V, Hølto J, et al.Self-healing high voltage electrical insulation materials[C]//IEEE Electrical Insulation Conference (EIC), Philadelphia, PA, USA, 2014: 241-244. [20] Vertkov A V, Evtikhin V A, Lyublinski I E, et al.Self-healing electrical insulating coating processes for vanadium alloy-lithium systems[J]. Fusion Engineering and Design, 2001, 58: 731-735. [21] Zhen Hu, Zhang Dayu, Lu Fei, et al.Multistimuli-responsive intrinsic self-healing epoxy resin con-structed by host-guest interactions[J]. Macromolecules, 2018, 51(14): 5294-5303. [22] Su Junfeng, Zhang Xiaolong, Guo Yandong, et al.Experimental observation of the vascular self-healing hollow fibers containing rejuvenator states in bitumen[J]. Construction and Building Materials, 2019, 201: 715-727. [23] Lang Sinuo, Zhou Qixin.Synthesis and characteri-zation of poly (urea-formaldehyde) microcapsules containing linseed oil for self-healing coating development[J]. Progress in Organic Coatings, 2017, 105: 99-100. [24] Sima Wenxia, Shao Qianqiu, Sun Potao, et al.Magnetically gradient-distributed microcapsule/epoxy composites: low capsule load and highly targeted self-healing performance[J]. Chemical Engineering Journal, 2021, 405: 126908. [25] Wang Youyuan, Li Yudong, Zhang Zhanxi, et al.Repair performance of self-healing microcapsule/ epoxy resin insulating composite to physical damage[J]. Applied Sciences, 2019, 9(19): 4098. [26] Caruso M M, Blaiszik B J, Jin Henghua, et al.Robust, double-walled microcapsules for self-healing poly-meric materials[J]. ACS Applied Materials & Inter-faces, 2010, 2(4): 1195-1199. [27] Matsuda T, Kashi K B, Fushimi K, et al.Corrosion protection of epoxy coating with pH sensitive microcapsules encapsulating cerium nitrate[J]. Corrosion Science, 2019, 148: 188-197. [28] Song Y K, Jo Y H, Lim Y J, et al.Sunlight-induced self-healing of a microcapsule-type protective coating[J]. ACS Applied Materials & Interfaces, 2013, 5(4): 1378-1384. [29] Baqir M A, Choudhury P K.Hyperbolic metamaterial-based UV absorber[J]. IEEE Photonics Technology Letters, 2017, 29(18): 1548-1551. [30] Smirnov J R C, Calvo M E, Míguez H. Selective UV reflecting mirrors based on nanoparticle multi-layers[J]. Advanced Functional Materials, 2013, 23(22): 2805-2811. [31] GB/T 1408B/T 1408.1—2016 绝缘材料电气强度试验方法[S]. 北京: 中国标准出版社, 2016. [32] Tanaka T, Kozako M, Fuse N, et al.Proposal of a multi-core model for polymer nanocomposite die-lectrics[J]. IEEE Transactions on Dielectrics and Electrical Insulation, 2005, 12(4): 669-681. [33] Ahmadi G, Guo Shiguang, Zhang Xinyu.Particle adhesion and detachment in turbulent flows including capillary forces[J]. Particulate Science and Technology, 2007, 25(1): 59-76.
2022, Vol. 37 
