Methylation-triggered fractionation of lignocellulosic biomass to afford cellulose-, hemicellulose-, and lignin-based functional polymers via click chemistry.

This paper reports a new concept for the biorefinery of lignocellulosic biomass where the derivatisation and fractionation of lignocellulose are accomplished at the same time. Methylation of sawdust of Larix kaempferi (Lamb.) Carriεave;re in dimethyl sulfoxide/tetrabutylammonium fluoride followed by fractionation provided three different polymeric derivative fractions: methylated cellulose, lignin, and hemicellulose. An aqueous solution of the methylated hemicellulose fraction was amphiphilic and possessed surface activity similar to that of industrially-produced methylcellulose. The azido-functionalised methylated cellulose and lignin fractions reacted with peracetyl propargyl β-cellobioside via Huisgen 1,3-dipolar cycloaddition followed by the removal of acetyl groups to yield a methylcellulose-block-cellobiose and methylated lignin-graft-cellobiose, respectively. An aqueous solution of diblock methylcellulose analogue, methylcellulose-block-cellobiose, formed thermoreversible supramolecular hydrogels near human body temperature. Methylated hemicellulose exhibited amphiphilic properties and acted as a surfactant. Methylated lignin-graft-cellobiose formed nanoparticles. Three major components in lignocellulosic biomass, cellulose, hemicellulose, and lignin, were successfully converted into three different functional materials. [ABSTRACT FROM AUTHOR]