Preparation of a biomass-derived imine hardener, biobased epoxy thermoset and their coating on cellulose nanofiber film for high-performance and energy-harvesting applications

Abstract

The design of biobased epoxy-cellulose nanofiber (CNF) films is highly sought after in the scientific community and industry sector due to superior comprehensive properties. Nevertheless, durable device performance is the primary challenge for CNF-based materials under humid working environments. Herein, we report (for the first time) a biomass-derived Schiff-based imine hardener for curing biobased epoxy resins, which, when applied as a coating improved the properties of cellulose nanofiber (CNF) films. The biobased epoxy-coated CNF film showed remarkable tensile strength (218.0 ± 4.2 MPa), Young's modulus (6.9 ± 0.2 GPa), thermal stability, and superior UV protection compared with those of neat CNF. Moreover, the biobased epoxy thermoset exhibited excellent chemical degradability in an acidic medium compared with that of the petroleum-based one. The biobased epoxy-coated CNF film was applied for a triboelectric nanogenerator (TENG) device. The latter exhibited a significant output power of 14.6 μW, with durability in humid conditions. We explored an effective strategy for all-biobased epoxy thermosets and their coating on CNF films but also demonstrated the potential of biobased TENG devices for energy harvesting.