Toughening Of Epoxy Resin By Modification With Epoxidized Pyridyl-Functionalized SBS

Pyridyl-functionalized SBS(SBSVP) was epoxidized by using formic acid and hydrogen peroxide in this paper, and the toughening of epoxy resin with the epoxide of SBSVP (ESBSVP) was also studied.The influence of reaction conditions such as formic acid, hydrogen peroxide, reaction temperature, reaction time, the concentration of SBSVP was also discussed by the determination of the epoxy group content, the decrease of double bond and the degree of side reaction. IR proved that there were new functional groups in the epoxidation product of SBSVP. Proton nuclear magnetic resonance spectroscopy showed that the new characteristic peaks existed in the epoxidation product of SBSVP, and proved that the order of reactivity for doube bonds was that 1,4-> 1,2-. Tensile property of epoxidized SBSVP was analyzed. The result showed that epoxidized SBSVP possessed higher tensile strength, lower elongation at break and deformation at rupture. DMA showed that Tg and E' of the epoxidation product of SBSVP became bigger. TGA analysis showed that the thermal stability of ESBSVP had slightly decreased.The effect of the content of ESBSVP and the different epoxidizing structure of ESBSVP on the toughening of epoxy resin was investigated. The results showed that with the increase of the content of ESBSVP, the flexural strength of epoxy resin reduced, the impact strength increased firstly and then reduced. The impact strength for the epoxy resin with 3wt% ESBSVP was improved for 85 percent than that for unmodified epoxy resin. SEM analysis indicated that there was remarkable toughness fracture surface morphology for the epoxy resin system modified with ESBSVP. DMA analysis results showed that the Tg of the modified epoxy resin increased slightly than that of unmodified epoxy resin in the meantime that the toughness of the epoxy resin was improved. The thermal stability of epoxy resin system was evaluated through TGA, TGA showed that there were a certain degree of increase. There was great effect of the epoxidizing structure for ESBSVP on toughening of the epoxy resin. Depending on the curing agent selected, the structure of ESBSVP such as epoxy group and hydroxyl group presented in the elastomer could be controlled to react with the curing agent more sufficiently in order to obtain more improved toughening.