| Epoxy resin not only has excellent adhesive properties, mechanical properties and corrosion resistance, but also has low cure shrinkage, dielectric loss and so on. So it is widely used in various fields including the coatings, adhesives, composites and cast molding. N, N, N’, N’-Tetralycidyl-4’,4’-Diaminodiphenyl Ether (TGDDE) resin is a tetra-functional epoxy resin. The advantages mentioned above are contributed to the phenyl structure units and higher epoxy functionality of the epoxy resin. TGDDE epoxy resin also has the poor toughness. Because the molecular structure containing an ether bond, it has good flexibility. The modified TGDDE epoxy resin can be used as a carbon fiber reinforced composite matrix material which is widely applied in the aerospace field, so it has good development prospects.This research is using aromatic amine and epichlorohydrin to synthesize the tetra-functional epoxy-TGDDE, and studies its properties. This research topic is divided into three main parts:1. Synthesis and process optimization of TGDDE epoxy resin.2. Preparation and properties of TGDDE epoxy resin adhesive.3. Comparative study on the performance of TGDDE epoxy resin and TGDDM epoxy resin.Firstly, in this study,4,4’-Diaminodiphenyl ether and epichlorohydrin were used to synthesize the products in additives CAT-18and CAT-78. Finally, TGDDE was synthesized through the post-treatment methods such as washing, distillation under pressure and so on. Besides, the epoxy value, viscosity and volatile matter of TGDDE were tested. We studied the effects of the proportion of raw materials, the reaction time and temperature on the synthesis of TGDDE product, then selected the optimum reaction process. Under this reaction condition, the epoxy value was0.79-0.82, the yield was88.0-92.0%, the volatile was less than one percent, the viscosity of the epoxy resin was2.0-2.8P after stored60days.Secondly, TGDDE was modified with the CTBN, and mixed with2-ethyl-4-tetramethyl imidazole, KH550and KH560of silane coupling agent, then the TGDDE epoxy adhesive was synthesized. We also tested the performance of TGDDE epoxy adhesive, including the tensile shear strength, gelation time, electrical properties and contact angle. Then we calculated the activation energy, surface energy of epoxy adhesive. We also analyzed the curing behavior of the resin system, and determined the activation energy, reaction order and curing temperature by DSC. The tensile shear strength was25.8MPa; the activation energy was about46.8-47.8kJ/mol, dielectric loss was low, the surface energy was40-50mJ/m2, significantly lower than that of water. By DSC analysis, we found the activation energy was48.5kJ/mol. The reaction order of the curing reaction process was0.875. The results showed that TGDDE epoxy adhesive had excellent performance.Finally, we studied the performance of TGDDE adhesive and TGDDM adhesive in different curing process. We found their activation energy were35.9kJ/mol and37.6kJ/moI, respectively. Both of them had low dielectric loss and surface energy. The water absorption was0.88%and0.96%.The studies also showed that the TGDDE adhesive is higher than TGDDM adhesives. The highest TGDDE adhesive was31.74kJ/mol and the highest TGDDM adhesive was25.8kJ/mol at room temperature. The tensile shear strength of TGDDE adhesive was23.158MPa at160℃and was11.652MPa at180℃. The tensile shear strength of TGDDM adhesive was20.135MPa at160℃and was9.812MPa at180℃.The conclusion is that TGDDE adhesive and TGDDM adhesive are high temperature resistant epoxy resin, and TGDDE adhesive is better. |
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