Study On The Basic Performance And The Double-Curing Behevior Of Epoxy (DADGEBA) Containing Allyl Group

As we known that epoxy resins were widely used as adhesives and matrix resin in composites. With the constant development of high technology, higher and higher request is put forward to the epoxy resin. So the enormous efforts have been made to study epoxy resins. This thesis bases on synthesizing a novel high performance epoxy resin (DADGEBA) containing double bonding and deeply study on the basic performance and double-curing behavior of epoxy DADGEBA. This thesis adopted the way of two steps to synthesize epoxy DADGEBA and deeply studied on the basic performance of epoxy DADGEBA by measuring NMR, FTIR, DSC, epoxy value, viscosity, shear strength and mechanics performance. And innovatively adopting sulfur as the curing agent of epoxy and deeply studying on the double-curing behavior, curing mechanism and the cooperating effect of sulfur and other curing agent.Results show that the epoxy value of DADGEBA is 0.436 and it has relatively lower viscosity in room temperature. IR spectra indicate the epoxy DADGEBA has double bonding in the molecular and it is a kind of multifunctional epoxy. DSC curves indicate that the epoxy resin has relatively longer pot time in room temperature though there has double bonding in the molecular. Mechanics performances show that epoxy DADGEBA has higher toughening and bending strength. For system S/DADGEBA, epoxy DADGEBA may carry out double curing. The curing reactions were likely contributed to two ways. A sulfur-sulfur bond was firstly broken to form two sulfur radicals when heated to relatively high temperature, and then a sulfur radical would captured a α-H atom in ally group to form a mercapto(SH) group and the ally group to form a carbon radical. The radicals (carbon or sulfur) resulted in radical polymerization reaction of double bond in the allyl group or the coupling reaction between two radicals. In the other hand, the epoxy group in DADGEBA was easily opened with the mercapto(SH) group to form C-S bond . Finally the system is cured by above two kinds of reactions. So by the cooperating effect of sulfur and other curing agent, the systems may carry out double curing and consequently it can enhance the cross-linking density, improve the thermal resistance and quicken the curing reactions and lay a stability foundation on the deep theory research.