Soy protein isolate (SPI), a ubiquitous and readily available biopolymer, has drawn increasing attention because of its sustainability, abundance, and low price. However, the poor mechanical properties, tedious performance adjustments, irreversible damage, and weak microorganism resistance have limited its applications. In this study, a facile but delicate strategy is proposed to fabricate an excellently selfhealable and remarkably antibacterial SPI-based material with high mechanical strength by integrating polyethyleneimine (PEI) and metal ions (Cu(II) or Zn(II)). The tensile strengths of the SPI/PEI-Cu-0.750 and SPI/PEI-Zn-0.750 films reach up to 10.46 ± 0.50 and 9.06 ± 0.62 MPa, which is 367.06 and 306.28% strength increase compared to that of neat SPI film, respectively. Due to abundant non-covalent bonds and low glass transition temperature of the network, both SPI/PEI-Cu and SPI/PEI-Zn films exhibit a satisfactory self-healing behavior even at room temperature. Furthermore, SPI/PEI-Cu and SPI/PEI-Zn films demonstrate high bacterial resistance against Escherichia coli and Staphylococcus aureus. This facile strategy of establishing dynamic networks in a biomaterial with numerous excellent properties will enormously expand the scope of its applications, especially in the field of recyclable and durable materials.
The development of magnesium oxychloride cement (MOC) contributes to reducing CO 2 emissions and recycling potash industrial wastes. Unfortunately, MOC is restricted by its water sensitivity, and fabrication of an MOCbased composite with combined water resistance and compressive strength is still challenging. Bioinspired by marine organisms, we herein proposed an organic−inorganic hybrid strategy to enable such a cementitious material. Under a sustainable development concept, we chose biobased chitosan (CS) and tartaric acid (TA) as organic components, which can provide more active sites for Mg 2+ ions in MOC to construct the stable double chelating network, thus promoting the generation of phase 5. The MOC− CS−TA composite realized the combination of a high compressive strength (52.25, 59.01, and 61.52 MPa at various curing ages, respectively) and an enhanced water resistance coefficient (0.88) compared with other MOC-based materials. The improvement can be attributed to the physical filling and protective effects of gel-like phase 5 and chelating products, which is similar to reef-building oysters and slush-buried sea rocks. This work provides a workable guideline for the practical applications of eco-friendly and highperformance building materials.
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