Design of mechanically robust, recyclable, multi-stimuli-responsive shape memory elastomers based on biological phytic acid and cuttlefish ink

Facilitating the utilization of biomass in the rubber field is a facile strategy to reduce environmental pollution and the carbon emission. Herein, biological phytic acid (PA) was served as an eco-friendly curing agent, and cuttlefish ink (CI) was acted as a photothermal trigger switch to fabricate multi-stimuli-responsive shape memory biobased epoxidized natural rubber (ENR) with mechanical robustness and recyclable ability. ENR was vulcanized by PA via the ring-opening reaction between phosphate groups of PA and epoxy group of ENR, leading to the construction of an impeccable cross-linking network and an adjustable Tg gradient, which endowed the elastomers with improved mechanical properties and shape memory effect. Meanwhile, the topology rearrangement occurred at elevated temperatures relied on phosphate transesterification, leading to excellent thermo-activated recyclable ability and reconfigurable shape memory performance of the elastomers. Additionally, CI acted as reinforced filler to enhance the ENR matrix, enabling elastomers to achieve a robust tensile strength of 21.4 MPa and tensile toughness of 30.4 MJ/m3, which was nearly 26.8 times and 11.3 times of the neat ENR, respectively. Exhilaratingly, CI also acted as photothermal trigger switch for the response to near-infrared light and sun, which realized the remotely multistage shape memory performance, demonstrating the potential application of ENR in the field of actuators without environmental pollution.