Interfacial engineering of bacterial cellulose composites with enhanced mechanical robustness and environmental stability via itaconic acid-based poly(urethane-amide)

초록

Bacterial cellulose (BC) is a promising sustainable polysaccharide material owing to its hierarchical nanofibrillar structure and high crystallinity; however, its inherent brittleness and moisture sensitivity limit its practical applications in flexible structural materials. Herein, an interfacial engineering strategy is developed to enhance the structure-property relationships of BC by impregnating its porous network with an itaconic acid (IA)-based bio-poly(urethane-amide) (PUA). The enhanced performance is attributed to conjugation-mediated electronic modulation, which strengthens interfacial noncovalent interactions between the elastomeric matrix and cellulose nanofibers, thereby improving load transfer efficiency within the composite. As a result, the composite exhibits a nearly 100-fold increase in elongation at break and an approximately 15-fold improvement in toughness compared to pristine BC. In addition, the material demonstrates a modulus of similar to 272 MPa at 2% strain and a tensile strength of 9.7 MPa, comparable to conventional synthetic leathers. The composite also shows excellent elastic recovery with negligible permanent deformation and a crease recovery of 86.1%, along with stable mechanical performance under exposure to water, ultraviolet irradiation, and representative solvents. These results demonstrate that interfacial engineering of bio-based polymers provides an effective and scalable route to design mechanically robust BC composites for sustainability-oriented structural material applications.

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