Thermal, mechanical and shape memory properties of an intrinsically toughened epoxy/anhydride system

A series of intrinsically toughened shape memory epoxy resins (SMEPs) were prepared by curing two bisphenol-A type epoxy resins containing two and six oxyethylene units (DGEBAEO-2 and DGEBAEO-6) with hexahydrophthalic anhydride in the presence of tris-(dimethylaminomethyl) phenol. The thermal, thermomechanical, mechanical and shape-memory properties of these SMEPs were systematically investigated by DSC, DMTA, tensile test and fold-deploy shape memory test, respectively. DSC and DMTA experiments showed that as the concentration of the DGEBAEO-6 increased, the glass transition temperature and storage modulus in the rubbery plateau of the SMEPs decreased gradually. The tensile stress at yield also decreased with increase in the relative content of DGEBAEO-6 and all the SMEPs exhibit a ductile fracture feature with the appearance of yielding, according to the uniaxial tensile test. The fold-deploy shape memory test showed that all the SMEPs showed a good shape memory effect with a combination of relatively high shape fixity and shape recovery.