Effect of CTBN Liquid Rubber concentration on mechanical properties of Dicy-Cured DGEBA based Epoxy Resins

Epoxy resins are widely used in many applications [1], due to their appropriate material properties including excellent mechanical and electrical properties, thermal and chemicalstability, high strength and resistance to creep. However, one of the most undesirable properties of epoxy resins is their verypoor fracture toughness. Therefore, much research has been carried out to enhance the toughness of the cured epoxy resins without a significant loss in other properties [2,3]. One of themost well-known methods is to incorporate various amounts of a reactive rubber into the epoxy matrix [1]. Among theliquid rubbers, carboxyl-terminated copolymer of acrylonitrile and butadiene (CTBN) has been largely used as a modifier forepoxy resins [4]. The enhancement in toughness is achievedbecause the elastomeric phase precipitates at some stage of the curing process into particles of very small size [1]. One ofpopular curing agent is dicyandiamide (Dicy) which is widely used as a latent curing agent in heat-cured epoxy resins forlaminates or prepreg fabrication, coatings, and adhesives. In this study, toughening of a diglycidyl ether of bisphenol-A (DGEBA) epoxy resin with CTBN has been studied. The mixture of DGEBA/CTBN is cured with Dicy which is novel and hasn’t studied yet