Xylan-tannic acid adhesive combined activated wood interface to construct ultrastrong cross-linking network bonding interface
Wenxing Li, Zhi Li, Tongda Liu, Guanben Du, Kelu Ni, Hongxing Yang, Hang Su, Sichen Liu, Chunyan Yin, Xin Ran, Wei Gao, Long Yang
Abstract
Biomass adhesives have long been a subject of widespread concern and study due to their cost-effectiveness and minimal environmental impact. In this study, an activated wood surface with epoxy groups (AWI) was created by uniformly applying 3-glycidoxypropyltrimethoxysilane (KH560) onto poplar veneer. Then the aminated xylan-oxidized tannic acid adhesive (2AX-OTA) was prepared based on the Schiff base reaction between the quinone of oxidized tannic acid (OTA) and the amine group of aminated xylan (AX). Eventually, the high-performance bonding interface was co-built by 2AX-OTA and AWI. The dry bonding strength of 2AX-OTA-AWI plywood achieved 3.86 MPa, while the wet bonding strength was measured at 2.41 MPa and 2.15 MPa after immersion in hot (63 °C)/boiling water for 3 h. FT-IR, 13 C NMR, and XPS chemical analyses demonstrated that a triple cross-linked network structure of the bonding interface was co-constructed by imine covalent chain bridges and epoxy-amine network. This triple cross-linked network structure plays a crucial role in enhancing water resistance. This study presents a novel approach to designing multi-cross-linked networks for the synthesizing of eco-friendly and high-performance bio-based adhesives.