Multidimensional Investigation of <scp>ILSS</scp> and Compressive Strength of <scp>CF</scp> ‐Reinforced Epoxy Composites

ABSTRACT Interlaminar shear strength (ILSS) and compressive strength are critical performance indicators for carbon fiber (CF) reinforced epoxy resin composites (CF/EP) in engineering applications. In this study, methyl tetrahydrophthalic anhydride (MTHPA) and tris(dimethylaminomethyl)phenol (DMP‐30) are used as the curing agent and catalyst, respectively, while amino‐terminated liquid nitrile rubber (ATBN) is served as the toughening agent. In parallel, an interpenetrating polymer network (IPN) derived from NCO‐terminated oligomers is introduced to synergistically enhance ILSS, compressive strength, and flexural strength. DMP‐30 regulates the curing mechanism of epoxy resin by controlling the reaction between hydroxyl and epoxy groups, thereby tuning the crosslinking density in the EP/MTHPA/DMP‐30 matrix. ATBN improves the toughness of epoxy resin through a chemical reaction between its amino groups and the epoxy matrix. Furthermore, NCO‐terminated oligomers are incorporated into the ATBN‐toughened EP/MTHPA/DMP‐30 matrix, forming an IPN‐modified composite via selective reaction between NCO groups and hydroxyl groups in the matrix. As a result of this multi‐dimensional optimization strategy, the composites achieved a maximum ILSS of 101.72 MPa, representing a 47.29% improvement, and a maximum compressive strength of 808.12 MPa, corresponding to a 71.84% increase.