Wood-Inspired Dynamic Covalent Cross-Linking Network for Ultrahigh Adhesion Strength, Desired Weather Resistance, and Closed-Loop Recycling Adhesives
Xuebin Lian, Yuanjian Li, Penghui Li, Y. Jin, Xinyu Zhao, Jinyan Li, Dehuan Kong, Shujun Zhao, Shuangfei Xiang, Feiya Fu, Xiangdong Liu
Abstract
The problems of strength–toughness trade-off and stability–switchability conflict make it a huge challenge to integrate exceptional adhesion and desired recycling performances into a single system. Inspired by wood cellulose molecular chain structure, a parallel-ordered dynamic boronic esters cross-linking network is presented by using 4-dimethylaminopyridine as a countercation stabilizing the boron center to induce boric acid to form ionic spiroborate linkage with linear hydroxyl-decorated epoxy polymer. The ionic spiroborate polymer network has a high cross-linking degree to contribute to structural stability and adhesion strength. Moreover, the unique ionic spiroborate bond cooperates with the parallel-ordered structure, providing a highly effective path and a rapid exchange rate and thus affording excellent closed-loop recycling properties. Given the effects, a superior adhesion strength of 30.86 ± 0.74 MPa is found along with an excellent debonding work of 64929 N m –1 . Also, adhesives show excellent environmental reliability. In addition, the prepared adhesives exhibit good chemical/physical recyclability and display 106.8% conservation of adhesion strength after 3 bonding and debonding tests. This work provides a strategy to construct high-performance adhesives that combine robust adhesion and recyclable properties.