| Epoxy resin is used more and more widely in the field of electricalinsulation. However, as the development of electrical equipment which requireslarge capacity and high voltage, the operation of equipment needs more strictsafety and reliability. The demands for electrical properties of insulating materialare also higher. As ordinary epoxy resin can not meet the requirement ofdielectric properties, the nanoparticles modified epoxy resin which is aimed atobtaining high dielectric properties becomes the focus of today’s relevantscholars.Epoxy/organic-montmorillonite nanocomposites were prepared withorganic-montmorillonite and different contents of montmorillonite by diglycidylether of bisphenol A. During the melting intercalation processesmontmorilloniteis is used as inorganic filler, octadecyl trimethyl ammoniumchloride is used as modifying agent and methylhexahydrophthalic anhydride isused as curing agent. The interlayer spacing and composition of montmorillonitewere measured by X-ray diffraction (XRD) and Fourier transition infraredspectroscopy (FTIR) before and after modification. The microstructure ofEpoxy/organic-montmorillonite nanocomposites with different contents ofmontmorillonite was characterized by scanning electron microscopy (SEM) andtransmission electron microscopy (TEM). The temperature dependence ofcomposites insulation resistance was verified using a high resistance meter andthe conductance characteristics which influenced by modifier, montmorillonitecontent and test temperature were also investigated. Dielectric strength wasmeasured to investigate the effect of the modifier, different montmorillonitecontent, the specimen thickness, the breakdown medium, and experimentaltemperature on breakdown strength of composites were discussed.The results of X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) show that the interlayer spacing of montmorilloniteincreased to1.9times, using octadecyl trimethyl ammonium chloride modified.The composites microstructure characterization shows that the right content oforganic montmorillonite was conducive to the formation of the stripping-typeepoxy resin/montmorillonite nanocomposites. The conductivity test resultsshow that the conductivity of the composites were increased with themontmorillonite filled, but the right content of organic montmorillonite caneffectively slow down the magnitude of its conductivity increases with increasingtemperature.The results of Breakdown test show that the organic montmorillonitecan increase the breakdown strength of epoxy/montmorillonite nanocompositesand the breakdown strength of pure epoxy resin were increased from1.13to1.47times with the different content of organic montmorillonite of composites. Notonly the specimen thickness and breakdown media affect the breakdown strengthof the composites, but also the experimental temperature on the breakdownstrength of the composites was also a considerable degree of influence. However,the right content of organic montmorillonite can enhance the breakdown strengthof the composites when the temperature is increasing. |
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