Thermally resistant and strong remoldable triple-shape memory thermosets based on bismaleimide with transesterification

It is still a great challenge to endow remoldable triple-shape memory thermosets (Rtri-SMTs) with high glass transition temperature (Tg) and high mechanical properties. Herein, two Rtri-SMTs with high Tg and high tensile properties, coded as BA1 and BA2, were developed through building unique dynamic crosslinked networks based on bismaleimide and novel bisallyl compounds with dynamic ester bonds (AEG1 and AEG2). The Tg values of BA1 and BA2 resins are 143 °C and 203 °C, respectively, much higher than those of Rtri-SMTs reported so far (10–110 °C); meanwhile, BA resins exhibit high tensile strengths (BA1: 81 MPa; BA2: 84 MPa) and moduli (BA1: 2165 MPa; BA2: 3233 MPa), which are severally at least about 1.3–1.4 and 3.2–4.7 times of those Rtri-SMTs in the literature, respectively. Besides the superiorly high thermal and tensile properties, both BA resins are able to be remolded and reconfigured through the re-arrangement of crosslinked networks induced by dynamic exchange reaction of ester bonds. The mechanism behind these attractive properties of BA1 and BA2 resins is discussed. Remoldable triple-shape memory thermosets with high glass transition temperature, high mechanical properties and good reconfigurability were developed.