Preparation of biomimetic functionalized hierarchical bamboo fibers for reinforcing plant protein-based adhesives

Natural materials (like teeth, bone, wood, bamboo, etc.) with organized hierarchical structures usually exhibit exceptional characteristics of both high stiffness and toughness. Bioinspired by this structure, design of functionalized hierarchical fibers has become an effective reinforcement strategy in fiber-reinforced polymer composites. In this work, bioinspired functionalized hierarchical fibers were constructed by anchoring catecholmodified metal-organic frameworks (MOFs) onto bamboo fiber surfaces which were then used as efficient strengthening phases to enhance the performance of soybean meal-based adhesives. The catechol-modified MOFs on fibers can form multiple interactions with a soybean meal matrix, whilst a hierarchical structures design for fibers can create a material gradient at the interval with a largely mismatched elasticity, which, remarkably, can decrease the stress concentration and thereby enhance energy dissipation in this region. As a result, the wet/dry shear strengths of the resultant adhesives were increased by 96.87% and 66.46%, and reached to 1.26 and 2.68 MPa, respectively. Also, the reinforcing mechanism of functionalized hierarchical fibers modified adhesives was proposed. We conceive that the functionalized hierarchical fibers as a bioinspired structural reinforcement has great potential for bionic adhesive applications. It also provides an effective reinforcement strategy for structural composites.

Automated summary

Bioinspired functionalized hierarchical fibers were constructed by anchoring catechol-modified metal-organic frameworks (MOFs) onto bamboo fiber surfaces to enhance the performance of soybean meal-based adhesives. The fibers with hierarchical structures can create a material gradient and decrease stress concentration, thus enhancing energy dissipation. The wet/dry shear strengths of the resulting adhesives were significantly increased by 96.87% and 66.46%.