Lignin, a plant constituent, is the second most abundant biopolymer on earth. Every year, the pulp and paper industry generates over 45 million metric tons of lignin as a by-product of chemical wood pulps and uses about 10 million metric tons of lignin as a component of mechanical wood pulps. The majority of the by-product lignin is being used internally as a low-grade fuel for the chemical pulping operation, while the lignin-rich mechanical wood pulps are being used mainly to make short-life paper products such as newsprint and telephone directories because of the light-instability of lignin. There is a tremendous economic incentive to find better uses of lignin and to expand the markets of mechanical wood pulps.
In Asia and other areas of the world where forest resources are less abundant, non-wood plant materials such as straw and bamboo have been used to make paper products for many centuries. The effective isolation and product development of lignin from chemical pulping of non-wood materials have become increasingly more important because internal use of the non-wood pulping spent liquors is difficult and the traditional way of discharging them to the environment is no longer acceptable.
This volume covers recent developments in chemical modification and utilization of lignin as a component of polymeric materials such as starch films, conducting polymers, polyurethanes and thermoplastics, and as a key building block to make carbon fibers, soil conditioners, nitrogenous fertilizers, and pulping catalysts. It also describes recent advances in chemical modification of lignin aimed at the photostabilization and upgrading of lignin-rich mechanical wood pulp and paper.