Developing Reprocessable shape memory thermosetting resins with high thermal resistance and strength through building a crosslinked network based on bismaleimide and epoxy resins

Abstract It is difficult to endow reprocessable shape memory thermosetting resins with outstanding heat resistance and high mechanical strength. Herein, a new kind of reprocessable shape memory thermosetting resins (DBE) are developed through building a crosslinked network based on N , N ′‐4,4′‐diphenylmethane bismaleimide (BDM), bisphenol A epoxy resin and 4,4′‐dithiodiphenylamine. The influence of the composition of DBE resins on their structure and comprehensive properties was studied. Results show that DBE resins have multiple phase structures. With the increase of BDM content of DBE resin, the glass transition temperature ( T g ), initial thermal decomposition temperature and flexural modulus increase, the impact strength and reprocessing efficiency decrease, while the flexural and tensile strengths increase initially and then decrease. 0.8DBE cannot be reprocessed, while 2DBE, 1.5DBE and 1DBE are reprocessable, and also have good shape reconfiguration and shape memory performances. Among them, 1DBE has the best integrated performance, which has attractively high T g (210°C), high tensile strength (76 ± 3.2 MPa), good reprocessability and excellent shape memory performance, its shape fixation rate and shape recovery rate reach 100% and 99.6%, respectively, overcoming the bottleneck problems of low heat resistance and insufficient mechanical strength of existing reprocessable shape memory thermosetting resins.