Assembly of Micro-Carbonized Lignin-Cellulose Mixture and Carbon Nanotubes via Interfacial Interactions to Prepare Composite Film with Superior Electromagnetic Interference Shielding and Mechanical Performance

Abstract

Conductive polymer composite (CPC) shows obvious superiority because of its flexibility and lightweight, which reveal high application potential in electromagnetic interference (EMI) shielding field. However, the poor mechanical properties, conductivity, and EMI shielding efficiency hinder its development. Researches show that engineering interfacial interactions (electrostatic interaction, van der Waals interaction, and π-π bridging, etc.) between carbon nanotubes (CNT) and polysaccharide matrix could program the microtopography of the composite, which is the key to solve above dilemma. Here, sodium lignosulfonate (L) and carboxymethyl cellulose (CMC) mixture were microcarbonized into novel carbon dots (CDs), named LCCD, where, the CDs were grafted on CMC chains. As-prepared LCCD chains were added into CMC and CNT suspension to fabricate CMC-LCCD-CNT film. CMC-LCCD-CNT film showed high EMI shielding (82.6 dB), conductivity (1386.57 S cm - 1 ), and mechanical performance (tensile strength of ~ 748.6 MPa, Young's modulus of ~ 28.6 GPa and toughness of 24.1 MJ m -3 ) on account of its strong interfacial interactions between LCCD chains and CNT. Notably, the addition of CMC in LCCD preparation could increase entanglement and plastic deformation between the components in CMC-LCCD-CNT film, which was conducive to engineer the interfacial interactions of composite and further improved its corrosion resistance, EMI shielding and mechanical properties, exhibited great potential for working in severe environments.