Multifunctional Lignin-Based Composite Materials for Emerging Applications

Abstract

Lignin exhibited numerous advantages such as plentiful functional groups, good biocompatibility, low toxicity, and high carbon content, which can be transformed into composites and carbon materials. Lignin-based materials are usually environmentally friendly and low cost, and are widely used in energy storage, environment, electronic devices, and other fields. In this review article, the pretreatment separation methods like hydrothermal process are illustrated briefly, and the properties and categories of technical lignin are introduced. Then, the latest progress of lignin-based composites and lignin-derived carbon materials is summarized. Finally, the current challenges and future developments were suggested based on our knowledge. It is expected that this review paper favored the applications of composites and lignin-derived carbon materials in the future.

Keywords: applications; carbon; composites; lignin; synthesis.

FIGURE 1

(A) Typical structure of lignocellulose (Zhu et al., 2020). (B) Precursors and (C) common interunit linkages (Luis Espinoza-Acosta et al., 2018).

FIGURE 2

(A) pH-responsive deformation of the lignin-based hydrogel by adding HCl and KOH solution; (B) Actuating performance of the lignin-based hydrogel for being hooked up (Dai L. et al., 2020).

FIGURE 3

Schematic diagram of NaOH/urea aqueous solution to depolymerize the alkali lignin to prepare low molecular weight lignin derivatives (Li et al., 2018).

FIGURE 4

(A) Preparation of a composite by blending PBAT and Eucalypt hydrothermal lignin via two strategies (Xiong et al., 2020); (B) Digital photos of 0%, 5%, and 10% lignin (from top to bottom) exhibiting the effect on print quality (Sutton et al., 2018).

FIGURE 5

Schematic diagram of [Amim]LS precursors for N-doped porous carbon material fabrication (Xu Q. Q. et al., 2020).

FIGURE 6

Illustration diagram of lignin esterification reaction (Dai Z. et al., 2020).