A soy protein-based adhesive with improved mechanical and electromagnetic shielding properties by employment of core@double-shell BT@PDA@PANI fillers

Abstract

Resolving indoor electromagnetic interference (EMI) and radiation pollution caused by electromagnetic waves have become paramount. Plywood is broadly used in interior decoration and give them EMI shielding function will be significant for addressing these issues. Herein, inspired by the mussel underwater bonding strategy and oyster, polydopamine (PDA) graft transition layer was introduced between inorganic BaTiO3 (BT) core layer and organic polyaniline (PANI) shell layer to construct controllable core@double-shell BT@PDA@PANI nanoparticles. The epoxide polymer and aldehyde-decorated carbon dots (CDs) were used as crosslinkers to form the covalent bonds and dynamic covalent bonds within the adhesive network. The core@double-shell nanoparticles were used as a reinforcing element and crosslinker to construct an organic–inorganic hybrid protein adhesive. This as-prepared protein adhesive exhibits remarkable improvements in wet shear strength (1.16 MPa), dry shear strength (1.97 MPa), and water resistance. Encouragingly, the plywood with in-situ formulated adhesives is an absorption dominated EMI shielding material and reveals an excellent EMI SET of 38.04 dB EMI in the X-band, significantly outperforming most of the reported synthetic materials. This outstanding performance is attributable to its superior conductivity and unique hierarchical structure of plywood. Therefore, this study offers a facile, environmentally-friendly, and economically feasible strategy for preparing high-performance adhesives to address indoor EMI problems.