| With the development of sciences, the technical requirements of adhesive is more and more strictly, the adhesive with low curing temperature and can be used in high temperature is an important study direction. Epoxy resin is important structure adhesives which had good peel strength and synthesize properties and used widely in industry. However, with conventional curing agents, it is fragility and could not be used at high temperature,the curing process of epoxy resin often showed slow gel time unless high curing temperature.In this work, the reaction mechanism and the factors influencing the structure and the adhesive properties of the epoxy resin adhesive were studied. For example, the structure and the amount of curing agent had great influence on the strength and curing rate of the adhesive. It was also found that the curing reaction time and the curing temperature also played an important role on the mechanical properties of epoxy resin adhesive system. Results showed that the higher the curing temperature, the faster the curing rate and the higher the adhesive strength.In addition, the influence of the addition of B4C on the performance of epoxy resin adhesive such as heat-resistance and mechanical properties was studied. The experimental result confirmed that the addition of B4C would improve the mechanical properties and the adhesive properties of the adhesive in certain degree. What is more, the adhesive performance was also influenced by the content of the B4C in the adhesive. The content of fillings affected the dispersion of B4C in epoxy resin was studied, and got the optimal level of B4C. The particle size of B4C also played an important role on the shear strength, the result showed that the smaller particle size,the better of the dispersion of B4C in epoxy resin, and the greater of the shear strength. The surface status of bonded joint was another important factor that affected the bonding ability of the epoxy resin adhesive. Two kinds of metal bonded material were used in the experiment: one was aluminum alloy, and the other was stainless steel, the adhesive strength of the adhesive on the stainless steel was larger than aluminum alloy.TG and DTG were used to study the thermal stability of several kinds of epoxy resin adhesive systems. It certified that the heat-resistant property of the sample 5# is the best, adding the LP-3 could reduce thermal stability. The effect of the kinds and the amount of curing agent on exotherm of epoxy adhesive system was further analyzed through DSG. DSC was also used to analyze the curing temperature and the curing reaction mechanism of the adhesive system.The IR spectrum was used to characterize the cured epoxy resin. The results showed that the curing time and the curing temperature had great effect on the curing process, improving the high curing temperature would increase the curing degree. The reaction mechanism of the epoxy adhesive was also analyzed through IR. IR spectra analysis indicated that the curing temperature was one of the important factors that influenced the property of epoxy resin adhesive.The fracture surface morphology of the system was observed through metallographic microscopy and scanning electron microscope (SEM), the results showed that the toughness of the curing system modified improved remarkably and the fracture surface morphology of the tough curing agent modified epoxy resin was found to display tough fracture feature. In addition,combined with metallographic microscopy and SEM pictures, it can be found that the dispersion of carbonate boron and epoxy resin was the most important factor at all the time. |
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