| Glass fiber reinforced epoxy resin composite materials as a good insulating material, is widely used in electrical equipment such as insulation sleeve. Due to the problem of the surface activity of the glass fiber, it can not form a good combination with the epoxy resin matrix, so that it's easy to make defects in the production and application of the process, and accelerate the aging of electrical equipment insulation. Plasma surface modification is a new rapid developing technology. It can deal with materials efficiently in a short time, and make glass fiber easier to combine with organic adhesives such as epoxy resin. In this paper, the glass fiber was modified by low temperature plasma, and the electrical and mechanical properties of glass fiber reinforced epoxy resin composites are studied.First of all, dielectric barrier discharge (DBD) is used to modify the glass fiber under low atmospheric pressure, and deal with Os, 180s, 360s, 540s. The changes of surface morphology and chemical composition of glass fiber after modification are investigated, and the relationship between the modification effect and the time of plasma treatment of glass fiber are analyzed.The experimental results show that there are different degree of etching traces on the surface of the glass fiber after different time plasma treatment, and the new oxygen-containing polar functional groups such as O-C=O have been successfully introduced. The interaction between the two can be well enhance the interface strength of glass fiber and epoxy resin.However, the plasma treatment effect is not enhanced with the increase of the time. Based on the experimental results of this paper, the best solution for plasma treatment of glass fiber under atmospheric pressure is 11kHz power frequency, 20kV working voltage, 70W discharge power,180s processing time.Secondly, use different contents of glass fiber which is modified by low temperature plasma reinforced epoxy resin, and the partial discharge inception voltage, AC short breakdown strength, tensile strength and bending strength of composite materials are tested. Combine with the cross-sectional morphology of the composites, the modification effect between the electrical and mechanical properties of composites are analyzed. It is found that the electrical and mechanical properties of composites are improved by using the modified glass fiber. From the surface morphology of glass fiber/epoxy resin composites, after plasma modification of glass fibers distributed more evenly in epoxy resin, and less holes due to the glass fiber pull out, more closely combined with epoxy resin. When the content of modified glass fiber is 20wt%, the partial discharge inception voltage and AC short breakdown strength of composites reach a maximum of 23.2kV and 33.5kV, increased by 6.9% and 3.4%. The tensile and bending strength of the modified glass fiber as 15wt% reach the highest, respectively 61.325MPa and 170MPa, increased by 29.1% and 22.4%.To sum up, the changes of the surface morphology of glass fiber caused by the chemical etching of low temperature plasma, as well as the introduction of polar groups,are the dominant processes in the surface treatment of glass fiber. The electrical and mechanical properties of the composites can be significantly improved by using glass fiber after plasma surface modification reinforced epoxy resin. When the content of the modified glass fiber reaches 20wt%?25wt%,the electrical and mechanical properties of the glass fiber / epoxy resin composite are optimized,which has certain reference value for the practical application of the composite material. |
PDF Full Text Request