Study on plasma modified silica powder epoxy resin composites

This work uses micrometer scale silicon powder as raw material, conducts plasma interface modification in a nitrogen atmosphere, and adds nitrogen elements to generate active groups such as amino groups on its surface to improve the dispersion of silicon powder, enhance the interface interaction between silicon powder and epoxy resin, and form Si–N bonds. To a certain extent, the absorption performance of silicon powder has been improved, which indicates the effectiveness of plasma modification of Si powder. The hardness of the modified composite material increased from 75.52 to 85.34 HA. Mechanical experiments have shown that the addition of 3% wt significantly improves the tensile strength of epoxy resin, increasing it from 16.47 to 22.67 Mpa. Further increase in dosage will lead to a decrease in tensile strength. After modification, the 3%, 5%, and 10% modified epoxy composite materials increased from 22.67, 9.94, and 5.67 Mpa before modification to 24.15, 14.52, and 12.75 Mpa, respectively. Using molecular dynamics simulation to verify the feasibility of plasma modification on epoxy composite materials, it was found that the simulation results were consistent with the experimental results, and the ultimate tensile strength of the modified composite materials was improved. The electrochemical impedance spectroscopy and salt spray test results show that the low-frequency impedance modulus of the composite coating modified by plasma interface is about one order of magnitude higher than that of the unmodified silicon powder composite coating. The coating containing 5 wt% plasma modified silicon powder exhibits the best corrosion resistance.