Effect Of Thermo-oxidative Aging On Breakdown Properties Of Epoxy/Montmorillonite Nanocomposites

The thermo-oxidative aging which reduces insulation life is occurred duringthe usage of insulation material. The material which is perpared using nano-particle and polymer can improve mechanical and thermal performance.This dissertation choosed Bisphenol A type epoxy resin and methylhexahy-drophthalic anhydride was used as curing agent. The montmorillonite which usedoctadecyl trimethyl ammonium chloride doing surface modification was used asnano-filler. The EP/O-MMT was prepared using melt intercalation method. Thedielectric properties of EP/O-MMT was studied after thermal aging process. TheTEM and SEM was used to characterize the micro characterization of nano-composite. The FTIR was used to analyze the properties of EP/O-MMT andcomposite. The dielectric frequency and AC breakdown was used to test thedielectric property of material before and after thermal aging. This article mainlystudied the content of montmorillonite and thermal aging time which willinfluence the breakdown property of composite material.The result of FTIR shows that octadecyl trimethyl ammonium chloridecationic of organic montmorillonite only has physical impact on montmorillonitelamellar. The lamellar skeleton of organic montmorillonite does not change. Thehydrophilicity of montmorillonite change into hydrophobicity. The TEM resultsshows that adding of montmorillonite can form peeling-up structure. The resultof breakdown shows that addition of montmorillonite can improve the breakdownstrength of composite material. But too much addition will reduce the breakdownstrength of composite material. As the aging processed, the breakdown strengthof pure eposy resin was lower than the material with appropriate addition ofmontmorillonite. But after aging the magnitude decrease of breakdown strength was also significant. The result of dielectric frequency spectra shows that theaddition of montmorillonite decrease the dielectric constant of composite. But thedielectric change with frequency is nearly the same when compared with pure EP.When the content of montmorillonite is3wt%, after480h thermal aging thebreakdown strength decreases about27%. Dielectric spectrum with the spectrumtest results show that the dielectric loss of the organic montmorillonite to joinwas reduced by the dielectric constant and loss factor of composite materials,When the frequency is60hz, the montmorillonite content of3wt%of thecomposites dropped25.9%compared with the pure EP dielectric constant,dielectric loss factor decreased by52.8%. Pure EP after480h thermal aging,dielectric constant increased by9.3%, t after480h aging. In comparison, thedielectric constant of material which contains3wt%montmorillonite increase22%.