Lignin Modification for Enhanced Performance of Polymer Composites

From waste to resource: advancements in sustainable lignin modification

“…121,125 Ester group functionalized lignin Lignin esters exhibit more flexibility and a reduced T g in contrast to pristine lignin, rendering them suitable for thermoplastic applications on their own or in blends. 126,127 Esterification of lignin is easily achieved by reaction with highly reactive electrophiles, such as anhydrides or acyl chlor-Scheme 11 Aldehyde-assisted fractionation of lignin with glyoxylic acid and subsequent epoxy resin synthesis; ( prepared by the authors, adapted from ref. 35 and 120).…”

“…Lignin esters exhibit more flexibility and a reduced T g in contrast to pristine lignin, rendering them suitable for thermoplastic applications on their own or in blends. 126,127 Esterification of lignin is easily achieved by reaction with highly reactive electrophiles, such as anhydrides or acyl chlorides, resulting in a complete functionalization of all alcohol groups, but also waste associated with byproducts, the use of bases, and the necessary synthesis of the mentioned electrophiles (Scheme 12). Koivu et al reacted softwood kraft lignin with acetyl (C 2 ), octanoyl (C 8 ), lauroyl (C 12 ), or palmitoyl (C 16 ) chloride to prepare lignin esters of different aliphatic chain lengths ( E complex : 6.65–8.07, Table 4).…”

Thermo-Blending of Biobased Poly(propylene 2,5-furan dicarboxylate) and Poly(lactic acid) with Improved Mechanical Performance

“…In recent times, there has been a growing interest in sustainable biocomposite products driven by consumer demands and environmental organizations worldwide. − The escalating levels of carbon dioxide (CO 2 ) in the atmosphere pose a substantial threat, necessitating the urgent utilization of biobased natural resources as alternatives to CO 2 -emitting sources. − Despite the wide-ranging applications of polymeric materials, discontinuing the production of plastic materials derived from thermoplastic, thermosetting polymers, and rubber is challenging. − Additionally, composite manufacturing industries heavily rely on petroleum-based resources. , In this context, exploring carbon-based materials sourced from nature presents a viable alternative. − Poly­(lactic acid) (PLA) has emerged as a promising and popular bioplastic due to its monomer’s derivation from natural sources like corn, making it a renewable and biodegradable polymer. ,, PLA exhibits higher tensile strength and Young’s modulus compared to synthetic polymer-based plastics, enhancing its competitiveness. − However, it possesses inherent brittleness, heat resistance, and limited crystallization capabilities, hindering its potential applications. − Nevertheless, with suitable physical or chemical modifications, PLA can be considered a carbon-neutral thermoplastic polymer.…”