Preparation and Performance Study of Ultra-lightweight In-situ Self-foaming Composite Insulation Cores

Linyao Wu; Yunpeng Liu; Le Li

doi:10.54097/5syhks40

Authors

Linyao Wu
Yunpeng Liu
Le Li

DOI:

https://doi.org/10.54097/5syhks40

Keywords:

Pillar insulation core; expandable microspheres; composite foam; microscopic morphology; thermal properties; breakdown strength; in-situ self-foaming.

Abstract

To achieve the lightweighting of pillar composite insulators, this study employs an in-situ self-foaming molding process to prepare expandable microsphere/epoxy composite insulation core materials. Using DU658 expandable microspheres as fillers and E-51 epoxy resin as the matrix, the core density was controlled at 0.35 g/cm³. Four types of specimens with resin mass fractions of 55%, 60%, 65%, and 70% were prepared. The effects of resin content on microscopic morphology (SEM), chemical structure (FT-IR), interfacial properties (dye penetration), thermal properties (DSC, TG, DMA), and power frequency breakdown strength were systematically investigated. Results indicate that resin content influences cell size and distribution by regulating the expansion space of microspheres and the matrix constraint. The 55% resin group exhibited the smallest cells with a concentrated distribution; the 65% group had the largest cell size and highest dispersion; the 70% group's cell distribution tended toward concentration again due to enhanced matrix encapsulation. FTIR testing confirmed that only physical bonding exists between the microspheres and the resin, with no chemical reaction. All specimens passed the dye penetration test, showing tight interfacial bonding. Regarding thermal properties, DSC results showed that the glass transition temperature increased from 85 ℃ to 109 ℃ with increasing resin content. TG analysis indicated that the initial decomposition temperature (T5%) of all specimens was above 192 ℃, making them suitable for long-term service below 200 ℃. DMA results showed the 60% resin group had the highest initial storage modulus (1250 MPa), satisfying rigidity requirements. Breakdown performance tests revealed a downward trend in power frequency breakdown strength as resin content increased; however, the breakdown strength of all specimens exceeded 30 kV/cm, meeting electrical standards, with the 55% resin group performing best. This study provides an experimental basis for the formulation and process optimization of lightweight insulation cores for UHV/EHV insulators.

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References

[1] Li Peng, Wang Rui, Ji Haoran, et al. Research and prospect of planning for low-carbon smart distribution network[J]. Automat ion of Electric Power Systems, 2021, 45(24): 10-21.(inChinese)

[2] Zhang Sheng. Prospects of China's Petroleum Refining and Petrochemical Industry under “Dual Carbon” Goals[J]. China Oil & Gas, 2022, 29(3): 41-46.

[3] Yun Baoji, Zhang Enshuo, Zhang Guo, et al. Optimal operation of anintegrated energy system consideringinte-grated demandresponse and a ‘dual Carbon’ mechanism[J]. Power System Protection and Control, 2022, 50(22): 11-19. (inChinese)

[4] SHANG Yong, WANG Zhe, YAN Huan, et al. Research exploration of Shanxi new type power system in the background of ‘dual Carbon’[J]. Power System and CleanEnergy, 2023, 39(12): 20-27. (inChinese)

[5] Zeng Peng, Wen Xiankui1, Tan Zhukui, et al. Analysis of the Evolution and Development of China’s Power System Under the Goal of Carbon Peaking and Carbon Neutrality Goals[J]. Construction Economy, 2023, 44(S02): 33-37.(inChinese)

[6] Liu Y P, Zhang M J, Liu H C, et al. The influences of silane coupling agents on the heat and moisture resistance of basalt fibre‐reinforced composites[J]. High Voltage, 2022, 8(1): 38-47.

[7] Yin Chengfeng, Xiao Zhang, Guo Yujun, et al. Method for detecting the pollution degree of naturally contaminated insulator based on hyperspectral characteristics[J]. High Voltage, 2021, 6(6): 1031-1039.

[8] Afolabi Olusegun A., Kanny Krishnan, Mohan T. P. Processing of Hollow Glass Microspheres (HGM) filled Epoxy Syntactic Foam Composites with improved Structural Characteristics[J]. Science and Engineering of Composite Materials, 2021, 28(1): 116-127.

[9] Sheng Wang Qun, Li Gang, Li Yanzhe, et al. Comprehensive simulation of snow crystal deposition and electric field characteristics of composite sheath improved porcelain cantilever insulator in a wind and snow environment[J]. Journal of Measurement Science and Instrumentation, 2022, 13(4): 379-389.

[10] Yang Xi, Wang Qingyu, Wang Haoran, et al. Transient electric field computation for composite cross-arm in 750kV AC transmission line under lightning impulse voltage[J]. IEEE Transactions on Dielectrics and Electrical Insulation, 2016, 23(4): 1942-1950.

[11] Kopparthi N R, Schuster J, Shaik Y P. Fabrication and Characterization of Bamboo—Epoxy Reinforced Composite for Thermal Insulation[J]. Open Journal of Composite Materials, 2024, 14(1): 15-32.

[12] Dong Weiwei ,Qian Danbo ,Xi Ying, et al.Preparation and properties of waterborne polyurethane coatings containing polyurethane-coated hollow glass microspheres[J].Progress in Organic Coatings, 2025, 208109490-109490.

[13] Liu Yunpeng, Li Le, Liu Hechen, et al. Hollow polymeric microsphere-filled silicone-modified epoxy as an internally insulated material for composite cross-arm applications[J]. Composites Science and Technology, 2020, 200(4): 108418.

[14] Wang Pucheng, Yang Na, Liu Dong, et al. Coupling effects of gamma irradiation and absorbed moisture on silicone foam[J]. Materials & Design, 2020, 195(1): 108998.

[15] Martin-Gallego M, Lopez-Hernandez E, Pinto J, et al. Transport properties of one-step compression molded epoxy nanocomposite foams[J]. Polymers, 2019, 11(5): 756-756.

[16] Song W, Tagarielli V L, Lee K Y. Enhancing the fracture resistance and impact toughness of mechanically frothed epoxy foams with hollow elastomeric microspheres [J]. Macromolecular Materials and Engineering, 2018, 303(12): 1800363.

[17] Stefani P, Barchi A T, Sabugal J, et al. Characterization of epoxy foams[J]. Journal of Applied Polymer Science, 2003, 90(11): 2992-2996.

[18] Cheng Qiyun, Sun Caixin, Zhang Xiaoxing, et al. Short-Term load forecasting model and method for power system based on complementation of neural network and fuzzy logic. Transactions of China Electrotechnical Society, 2004, 19(10): 53-58.

[19] Roggendorf C, Schnettler A. Accelerated hydrothermal aging of epoxy resin based syntactic foams with Polymeric Microspheres. IEEE Transactions on Dielectrics and Electrical Insulation, 2012, 19(3): 973-980.

[20] Yu Wei, Qian Meng, Li Huijian. Elastic and plastic properties of epoxy resin syntactic foams filled with hollow glass microspheres and glass fibers[J]. Journal of Applied Polymer Science, 2016, 133(46): 44188.

[21] Kessler M, Schnettler A. Investigation of the DC breakdown mechanism in elastic syntactic foams[J]. IEEE Transactions on Dielectrics and Electrical Insulation, 2010, 17(3): 898-905.

[22] Li Xiudi, Zhu Ming, Tang Xuemei, et al. Influence of hollow carbon microspheres of micro and nano-scale on the physical and mechanical properties of epoxy syntactic foams[J]. Rsc Advances, 2015, 5(63): 50919-50928.

[23] Wu Xinfeng, Tang Bo, Yu Jinhong, et al. Preparation and investigation of epoxy syntactic foam (epoxy/graphite reinforced hollow epoxy macrosphere/hollow glass microsphere composite)[J]. Fibers and Polymers, 2018, 19: 170-187.

[24] Bharath K B, Doddamani M, Zeltmann S E, et al. Effect of particle surface treatment and blending method on flexural properties of injection-molded cenosphere/HDPE syntactic foams[J]. Journal of materials science, 2016, 51: 3793-3805.

[25] Rousseau C-E, Plume G, Goñi M, et al. Behavior of syntactic foam under plate impact[J]. Mechanics Research Communications, 2017, 83: 1-5.

[26] Kaur M, Jayakumari L S. Consequence of cenosphere loading on hygrothermal, thermal, and mechanical properties of epoxy syntactic foams[J]. Journal of Cellular Plastics. 2019, 55(3):297-318.

[27] Samsudin S S, Ariff Z M, Zakaria Z, et al. Development and characterization of epoxy syntactic foam filled with epoxy hollow spheres[J]. Express Polymer Letters. 2011, 5(7).

[28] Ozkutlu M, Dilek C, Bayram G J C S. Effects of hollow glass microsphere density and surface modification on the mechanical and thermal properties of poly (methyl methacrylate) syntactic foams[J]. Composite Structures, 2018, 202: 545-550.

[29] Zheng Luyu, Wu Mei, Sun Dayu, et al. Development of a flame-retardant epoxy resin with high glass transition temperature and transparency based on a diphenylphosphine oxide derivative[J]. Frontiers of Chemical Science and Engineering, 2025, 19(8): 33-44.

[30] Lakouraj M M, Rahpaima G, Zare N E. Effect of functionalized magnetite nanoparticles and diaminoxanthone on the curing, thermal degradation kinetic and corrosion property of diglycidyl ether of bisphenol a-based epoxy resin[J]. Chinese Journal of Polymer Science, 2014, 32(11): 1489-1499.

[31] Jiang Shuajun, Meng Weifeng, Wan Yongqing, et al. Pyrolysis Mechanism of a cyclotriphosphazene-based flame-retardant epoxy resin by reaxFF molecular dynamics[J]. China Petroleum Processing & Petrochemical Technology, 2023, 25(03): 136-152.

[32] Yang K-R, Dai J-Y, Wang S-P, et al. Bio-based epoxy composites demonstrating high temperature breakdown strength and thermal conductivity for high voltage insulation[J]. Chinese Journal of Polymer Science, 2025, 43(1): 40-52.