| Research on synthesis and application of the epoxy resin has become the focus in the high temperature resistant material because of its high bonding strength, high mechanical properties, excellent electrical insulation properties, good solvent resistance, and other good features.Using4,4’-diaminodiphenylsulfone (DDS), epichlorohydrin (ECH) and sodium hydroxide (NaOH) as the basic raw material epoxy resin--N, N, N’, N’-tetralycidyl-4,4’-diaminodiphenylsulfone(TGDDS) of high temperature resistance was synthesized in this research.Owing to the phenyl structure units and the strong electron-withdrawing-sulfuryl, TGDDS have stable physical and chemical properties. Therefore, synthesized TGDDS have excellent temperature resistance, good transparency, high epoxy value, excellent stability, etc. It will serve as a kind of important matrix of high performance composite materials.This research topic is divided into four main parts:1. Synthesis and characterization and performance of DDS type polyfunctional epoxy resin.2. Preparation of TGDDM epoxy resin adhesive and study of its curing kinetics.3. Study on performances of TGDDS epoxy adhesive.4. Study on the properties of TGDDS epoxy compared with TGDDM epoxy adhesive.Firstly, the suitable catalyst---TCAT-172was foud to transform4,4’-diaminodiphenylsulfone (DDS) and epichlorohydrin (ECH) into TGDDS resin under conditions of the existence of additives---C-98, alkaline environment, washing, vacuum distillation. The TGDDS is brown and solid in room temperature. Then, the product was characterized by FTIR. The effect of the amount of catalysts, the time of ring opening reaction and the closed-loop response, the temperature of ring opening reaction and the closed-loop, the proportion of raw materials and the time of distillation under pressure were studied to select the optimum reaction process. Under this reaction condition, the final yield of product was90%-92%. the epoxy value was0.70-0.71. the volatile matter was0.95%-1.0%.Secondly, TGDDS was modified with CTBN, then mixed with2-ethyl-4-tetramethyl imidazole and S330, then the TGDDS epoxy adhesive was synthesized. The curing kinetics of TGDDS/2,4-EMl curing systems were explored by differential scanning calorimetry (DSC). Morever, the proper curing process was determined, namely,100℃/0.5hâ†'110℃73hâ†'>120℃/0.5h, and the curing kinetic equation were calculated,which was da/dt=4.39×106exp(-55030/RT)(1-a)0.8930Thirdly, the mechanical properties of TGDDS epoxy adhesive were investigated under different formula composition and curing process, then, the optimal proportion was determined and also the curing process was examined. At the same time, the curing process optimized further and confirmed as the following:room temperatureâ†'100℃/0.5hâ†'110℃/3hâ†'120℃/0.5h. The tensile shear strength, gelation time, viscosity, bibulous rate, electrical properties and contact angle were tested, then relative dielectric and surface energy were calculated. The tensile shear strength was23.8MPa in room temperature, and13.8MPa in100℃, bibulous rate was around1.22%, relative dielectric constant is in the range of3.83-3.95, surface energy was44.5mJ/m2and the hydrophobic performance was good.Fourthly, under the same curing process conditions, properties of TGDDS epoxy compared with TGDDM epoxy adhesive were studied, such as, mechanical properties, physical and chemical properties. The results showed that the ratio of actual epoxy value and the theoretic epoxy value was above83%for both of the two kinds of epoxy resin. The apparent activation energy of TGDDS/2,4-EMI system and TGDDM/2,4-EMI system were51.4kJ/mol and49.3kJ/mol respectively, which were within acceptable range. The electrical insulation properties of cured TGDDS epoxy adhesive were better than that of cured TGDDM epoxy adhesive.They both had small bibulous rate, low surface energy. |
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