MPN-GE Bilayer Interphase Construction: Green Modification Derived from Biomass and Synergistic Enhancement of CFRP

The interfacial performance of carbon fiber-reinforced polymer composites (CFRP) is a key factor restricting their wide application in aerospace and other fields. In this paper, based on naturally derived biobased materials, we propose a green, layered surface modification strategy. First, metal-phenolic networks (MPN) are self-assembled on the carbon fiber surface as the bottom layer, with the help of the coordination of tannic acid (TA) with Fe³⁺ to form a three-dimensional cross-linked structure. Then, through the phenol-amine codeposition effect, gelatin (GE) is introduced as the top layer to construct an MPN-GE bilayer interfacial structure. The results show that the interlaminar shear strength, flexural strength, and transverse fiber bundle tensile strength (TFBT) of the modified CFRP are increased by 60.88, 126.66, and 143.32%, respectively, compared to the unmodified composites. The biobased, nontoxic modification system adopted in this paper provides a new idea for the green, efficient interfacial engineering of high-performance CFRP.