Among natural polymers, lignin is unique in that it is highly random instead of being linear and structured. Lignin in wood is a crosslinked polymer that has gelled. Delignification or pulping represents a severe degradation of lignin by chemicals. In molecular terms, this process involves cleavage of various chemical bonds so that the insoluble lignin gel is reduced to molecular fragments of various sizes. Physical and chemical properties of lignin gel and sol (the degraded and dissolved fraction) can both be accounted for with the "tree-like" molecular model formulated by Flory and Stockmayer. A quantitative theory based on this model has recently been developed by the Principal Investigator. This model requires substantial computation to interpret the degradation data of lignin. Molecular weight distribution is the most important information in any stage of delignification; measurements of molecular weights are possible with modern instrumentation. Measured and calculated data will allow the calculation of structure-property relations of lignin and its contribution as an energy and material source.Anticipated Results/Potential Commercial Applications as described by the awardee:A molecular biology of lignin may be developed as a result of a better understanding of the polymeric properties of lignin. A well-developed macromolecular chemistry and biology will facilitate the application of lignin, wood, and their energy conversion.
