| Epoxy resin is widely used as insulation material in the field of electronic and electrical because of its excellent comprehensive performance such as strong adhesion and cohesive strength,low shrinkage,good mechanical,dielectric properties and creep resistance. At the same time epoxy resin has some shortcomings:lack of heat resistance,poor toughness and arc resistance. With the development of the inorganic particles refinement and particle surface treatment technology, especially the emergence of nano-fillers, these inorganic particles filled in epoxy resin could combine the rigidity, dimensional stability and thermal stability of inorganic with the processing and kinds of good comprehensive properties of epoxy resin to meet the requirements of the composite materials.This paper used mica as filler to improve the electrical properties especially the arc resistance of epoxy resin. Researched the influence factors on the arc resistance dielectric properties,conductivity properties and static mechanical properties of composites materials as well as changing rules. Analysed the changes of heat resistance and microcosmic configurations of composites by SEM and DSC.We prepared different samples by use different kinds of epoxy resin:E-51,AFG-90,TDE-85 and adding multifunctional modifier to these resins; different curing agents:MeTHPA,modified amine(laboratory-made). DDM. D400; different promoters:DMP-30 and imidazole. The DSC and arc resistance results of these sample showed that as the Tg increased, the arc resistance also increased. Different gloss of the arc resistance of E-51/MeTHPA/DMP-30 system increased with the increasing gloss. When the gloss was between 20 and 60, the arc resistance come to the best. However, continuing to raise the gloss, the arc resistance reduced and the change rates were relatively large. The arc resistance was only 75s while the gloss was 110.In this study we used four different particle size:500 mesh,1000 mesh,2000 mesh and nano-scale; different amounts:5%,10%,15%,20%,25% and 30%. After added mica, the Tg of the curing had greatly improved and the arc resistance was much higher than pure epoxy resin. When the mica content came to 30%, the arc resistance increased by 60s.Adding micron mica, the dielectric constant of materials changed relatively flat. But adding nano-mica, it had a slight increase. There was the maximum increase level when the mica content was 10%. The dielectric loss of composites increased with mica filler, with the undulating shape change. Adding 500 mesh mica, the tanδvalues changed little. When the particle size became smaller, the dielectric loss of samples increased relatively higher, especially to the nano-mica. It reached the maximum when the mass fraction was 10%, and then decreased. Overall, the trend increased. Compared with the pure epoxy, adding mica made the volume resistivity declined. The volume resistivity gradually decreased as the addition continued to increase. When filled with nano-mica, the volume resistivity declined from 1.25×1016Ω·cm to 1.38×1015Ω·cm, while the surface resistvity was on the increase. Different particle size did different influence degree to the materials. As the particle size decreased, the augmented trend of the surface resistivity declined. Compared with the other three kinds, adding 500 mesh mica did the greatest impact to surface resistivity, the maximum reached 1.04×1015Ω.Though the testing on the static mechanical properties of the modified epoxy resin, the results showed that:when the nano-mica content was 5%, the toughness came to the maximum(19.6KJ-m-2), was 192% of the pure epoxy resin (10.2KJ·m-2),but using micron-mica filled, the increscent values would be much lower. The bending strength and tensile strength increased when the content was very little(≤5%). As the content continued to increase, the strength declined, while the modulus of elasticity wavily increased.
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