A Review on the Lignin Biopolymer and Its Integration in the Elaboration of Sustainable Materials

Abstract

Lignin is one of the wood and plant cell wall components that is available in large quantities in nature. Its polyphenolic chemical structure has been of interest for valorization and industrial application studies. Lignin can be obtained from wood by various delignification chemical processes, which give it a structure and specific properties that will depend on the plant species. Due to the versatility and chemical diversity of lignin, the chemical industry has focused on its use as a viable alternative of renewable raw material for the synthesis of new and sustainable biomaterials. However, its structure is complex and difficult to characterize, presenting some obstacles to be integrated into mixtures for the development of polymers, fibers, and other materials. The objective of this review is to present a background of the structure, biosynthesis, and the main mechanisms of lignin recovery from chemical processes (sulfite and kraft) and sulfur-free processes (organosolv) and describe the different forms of integration of this biopolymer in the synthesis of sustainable materials. Among these applications are phenolic adhesive resins, formaldehyde-free resins, epoxy resins, polyurethane foams, carbon fibers, hydrogels, and 3D printed composites.

Plant Polysaccharides in Engineered Pharmaceutical Gels

“…An example of a lignin-derived polymer is polyurethane (PU), which polyol-rich structure of lignin act as a monomer in the PU synthesis. Other resins based on lignin are also available, such as epoxy, and in addition to it, lignin can act as a carbon fiber used as fillers in polymeric composites [ 91 ]. Unusual applications of lignin-based materials are binders, separators, and electrolytes (anodes and cathodes) for rechargeable batteries as lignin is itself electrically active [ 92 ].…”

High Concentration Lignin Biocomposites with Low Melting Point Biopolyamide

“…Biomass feedstocks, such as plant oils, fatty acids, cellulose, and lignin, have been considered potentially sustainable alternatives to producing polymers [60][61][62]. In this context, lignin has been deeply studied for its potential integration into different new materials as a sustainable replacement for some petroleum derivatives and chemicals [63,64]. Likewise, castor oil has been introduced as a promising source for developing several renewable and sustainable polymers such as polyurethanes, polyesters, epoxy-polymers, and polyamides [65,66].…”

Progress in Bio‐Based Phenolic Foams: Synthesis, Properties, and Applications

“…The exponential increase in the recent research for converting bioresources to valuable products is indicative of their importance. Significant advancements have been observed in the last decade in the bioresource conversion and modifications and their applications in foam production 179–181.…”