The modification of epoxy resin by aldehyde-terminated liquid rubber with side epoxy groups
Epoxy resin is one of the main thermosetting resins.Although traditional toughening methods can improve the toughness,other properties,such as rigidity and strength,tend to decrease.Therefore,it is of great significance to maintain or even improve the rigidity and strength while increasing the toughness of epoxy resins.In this paper,the aldehyde-terminated liquid styrene-butadiene rubber and polybutadiene rubber with side epoxy groups(EATSBR and EATPB)were prepared by the epoxidation-cracking method.Then,the flexible chains were introduced into the epoxy resin cross-linking network through co-curing by utilizing their reactive groups to form a special topology where the hard and soft chains were cross-linked with each other,and the cross-linking density was moderately enlarged.It has been found that both of the two liquid rubbers can effectively improve the toughness of epoxy resin and significantly enhance its rigidity and strength.Moreover,EATSBR has a better toughening and strengthening effect on epoxy resin since existence of styrene units in its macromolecular chain can better disperse the rubber in the epoxy resin matrix.The comprehensive modification effect was the best when the epoxidation ratio of EATSBR is 5.8%and its addition amount is 1 wt%.
epoxy resinliquid rubber with side epoxy groupsco-curingtoughening modification