Effect of rubber modification on fracture toughness properties of glass reinforced hot cured epoxy composites

In this study, carboxyl-terminated butadiene acrylonitrile (CTBN) added to epoxy resin to improve the fracture property of resin and glass reinforced epoxy (GRE) composites. Tensile strength and Young’s modulus of unreinforced resin with/without modifier were examined. Plane strain fracture toughness (KIC) was calculated using single-edge-notch specimens that tested in three point bending (3PB) geometry. Results indicated that fracture toughness improve through increasing rubber modifier content. Fracture surfaces of the 3PB specimens were observed by using optical microscope and scanning electron microscope. Tensile properties perpendicular and parallel to the fibers direction were tested, respectively. GRE composite interlaminar fracture toughness increased with increasing rubber modifier in composite.

► A liquid rubber modifier was employed as toughening agents in hot cured epoxy.
► Fracture toughness of modified resin increased by CTBN content.
► Longitudinal tensile strength of composites decreased with increasing the CTBN.
► Transverse tensile strength of modified GRE increased with increasing CTBN content.
► Interlaminar fracture toughness of modified GRE increased by CTBN addition.