Solvent-free modification of lignocellulosic wood pulp into a melt-flowable thermoplastic

This paper reports on a flowable lignocellulosic thermoplastic prepared from forestry biomass by solvent-free acetylation. The non-solvent approach relies upon a functionalizing agent derived from benzethonium chloride (hyamine) and sulfuric acid, which was chose for its similar wetting attributes to an ionic liquid for the lignocellulose but was much less expensive to use. Besides acetylation, this functionalizing agent became chemically bonded to the lignocellulose by the sulfate group formed in situ, as demonstrated by 13C NMR, infrared and elemental analysis. This attached species appeared to contribute strongly to the flowable nature of the product. The modified material showed good melt flowability by compression molding, as demonstrated in this study by the production of semi-transparent films and was characterized by differential scanning calorimetry and dynamic mechanical analysis. An experimental investigation of reaction parameters was included in the study, exploring the mechanism by which the cationic functionalizing agent modified the structure of lignocellulose.Graphic Abstract