| Recently, the demand for high performance materials has increased tremendously due to the rapid development of microelectronics and aerospace industries. Because of its excellent properties, epoxy resins are widely used in electronic packing materials, printed circuit board and adhensives. Develop new type of curing agents, which are very important in the application of epoxy resin, is an impressive method to improve the overall properties of the composite materials.In this thesis, a maleimide compound containing hydroxyl group, N-4-hydroxyphenyl maleimide, was synthesized and it was used as curing agent for the Bisphenol-A type novolac epoxy resin. The curing kinetics and the property of the cured resin were further investigated. The brief contents were shown as follows:Firstly, N-4-hydroxyphenyl maleimide was synthesized with a two step method using maleic anhydride and p-aminophenol as raw materials. It was further used as curing agent for the Bisphenol-A type novolac epoxy resin and the suitable cure condition was investigated. Thermogravimetric analysis (TGA) of the cured resin showed that the5%weight loss temperatures and10%weight loss temperature were392℃and421, respectively. And the char yield is59.3%at800℃. All the results showed the prepared cured resin have the excellent thermal stability.Secondly, the curing kinetics of HPM/Bisphenol-A type novolac epoxy resin system were investigated by non-isothermal differential scanning calorimetry (DSC) at different heating rates (2,5,1015and20℃/min). Three different methods (Ozawa, Kissinger and Flynn-Wall-Ozawa) were employed to research the cure kinetics of B-pbf. Ozawa and Kissinger methods showed that the activation energy (Ea) of the system were78.0and85.3kJ/mol, respectively. The Flynn-Wall-Ozawa method provided the change of activation energy Ea values as a function of the degree of conversion. The autocatalytic kinetic model was found to be the best description of the investigated curing reactions. Non-isothermal DSC curves obtained from the experimental data showed a good agreement with that theoretically calculated. In addition, the appropriate curing reaction conditions were obtained.Thirdly, the isothermal cure kinetics of HPM/Bisphenol-A type novolac epoxy resin system was also investigated under different cure temperatures. At a given temperature, the reaction rate increased with conversion initially and passed through a maximum, and then gradually slowed down, finally tending to zero. Moreover, at a given time, a higher isothermal curing temperature gained a higher reaction rate. All the results further demonstrated that the system was cured under the autocatalytic kinetic model. The constants in the Kamal equation as apparent non-autocatalytic rate constant, apparent autocatalytic rate constant and reaction order were calculated accordingly. |
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