ABSTRACT
Outside of the plant, lignin is useful as a component of the diet of ruminant mammals; a soil property improver in the process of natural decay; and a source of peat, lignite, and coal. The most common use of lignin from pulping operations or ethanol from biomass processes is as a fuel. Other uses for lignin is of three large groups, two of which require chemical modification of the biopolymer. They are: breaking lignin down into component aromatics or repeat units, using the biopolymer as extracted from the wood, and adding to the lignin biopolymer, treating it as a starting material to be built on to make useful materials. Extensive studies on the modification of lignin by graft copolymerization have been made because of the enormous mass of kraft lignin produced each year by the pulp and paper industry. Graft copolymerization sharply changes the properties of lignin and allows useful products to be made from this underutilized portion of biomass.
