A new strategy to improve the toughness of epoxy thermosets by introducing the thermoplastic epoxy

A novel thermoplastic epoxy (TPE) was constructed through the solution polymerization process between diglycidyl ether of bisphenol A (DGEBA) and aniline to improve the performance of epoxy thermosets. Its cure kinetics, molecular structure, thermal and mechanical properties were investigated. Due to the similar chemical structure, the TPE exhibits excellent compatibility with DGEBA and DGEBA-based thermosets. The results of the mechanical properties of cured TPE/DGEBA composites demonstrate that the appropriate content of TPE (15 phr) can significantly improve the mechanical properties including the tensile strength, tensile fracture strain, flexural strength, flexural fracture detection and fracture toughness, which is associated with the formation of semi-IPN structure of TPE and DGEBA-based thermosets. The corresponding mechanism for enhanced properties of TPE/epoxy composites was investigated deeply by scanning electron microscope. And, the tensile and flexure modulus, glass transition temperature and thermal stability of TPE modified DGEBA based thermosets demonstrates a slightly decrease tendency with the addition of TPE, which can be attribute to the coupling effect between the uncrosslinked chain structure of TPE and the strong interaction of hydroxyl between TPE and DGEBA thermosets. • Thermoplastic epoxy (TPE) was synthesized from bisphenol A epoxy and aniline. • The TPE exhibited excellent compatibility with epoxy and epoxy thermosets. • Introduction of TPE could significantly improve the toughness of epoxy thermosets.