Structure-s And Properties Of Epoxy Resin Modified By Carboxyl-terminated Butadiene Acrylonitrile(CTBN) Copolymer

Epoxy resin is a kind of important thermosetting resin, which has the advantages of good adhesion, excellent mechanical properties, abrasion resistance and low cost. At present, it plays a very important role in many fields, such as adhesive, construction, aerospace, electronics, electric and so on. But, it is difficult to meet the requirements of engineering technology and its application is restricted, because of its curing product brittle, poor fatigue resistance, poor impact toughness and so on. Therefore, it has become a topic of concern for toughening modification of EP with liquid carboxyl terminated butadiene acrylonitrile(CTBN) rubber.For the moment, the research on toughening modification of EP with CTBN is as follows: first of all, CTBN/EP prepolymer is prepared by CTBN and EP reaction. And then, high temperature curing is implemented. Finally, analyzing its performance is needed. But, the performance comparison between CTBN/EP prepolymer and curing product of CTBN/EP mixture is rare. In this paper, CTBN/EP prepolymer and curing product of CTBN/EP mixture are in the low and high temperature curing by flexible curing agent(Polyether amine). The thesis studies the effect of factors on system performance. The factors are curing temperature, matrix selection and the content of CTBN.In order to prepare CTBN toughening epoxy adhesive, the bisphenol a type epoxy resin E-44, E-51 are respectively used as adhesive matrix, D-230 polyether amine as a curing agent, ethylene glycol diglycidyl ether as the diluents, Dimethyl silicone as defoamer, and the EP was toughened by chemical copolymer and physical blending each, the bubbles in the system was eliminated by vacuum deaeration technique. To identify the mechanical properties of the optimal ratio of adhesive, the radio of E-44 and E-51, the curing temperature and the content of CTBN is explored the effect on elongation, impact strength, tensile strength, young’s modulus, shear strength. The changes of mechanical properties are also researched when the adhesive curing in low and high temperature. At last the research tries to explore the toughening mechanism, getting a theoretical basis for process selection on different temperatures.The toughening modification of EP is investigated by reacting with different contents of CTBN, which is proved to be one of the most effective toughener for resins. Then the structures of CTBN/EP prepolymers and mixtures, as well as the properties of them, are characterized using corresponding standard methods. The FT-IR spectra confirms the formation of the functional ester group, which was generated by the reaction between the epoxy group of epoxy resin and the terminal carboxyl group of CTBN. The mechanical properties of CTBN/EP systems are investigated by the impact failure tests, and the results indicate that the increasing of CTBN in the systems contributes to better mechanical properties. The research results also show the shock resistance of prepolymers is significantly better than that of mixtures at the lower curing temperature, while there is no significant difference between the two at higher curing temperature.