The field of lignin-based polymeric materials and composites has seen great growth in the past 10 years, although the field still has room to grow. To develop bio-based polymeric materials to replace those from petroleum-based sources will require significant progress in several different areas. Methods to isolate more useful lignin-based chemical products, such as benzene, toluene, or xylenes, must be developed. In addition, methods to chemically functionalize lignin to synthetically useful products without the use of expensive reagents or complicated synthetic routes must be identified. While lignin model compounds have been used to elucidate the potential reactivity of lignin, more structurally relevant systems such as those prepared by Lancefield and Westwood should be utilized to study new depolymerization and upgrading techniques. By investigating the most structurally relevant and well-defined materials, newly developed techniques are more likely applicable to naturally occurring lignin. Polymerization systems and reactions should be designed to allow for “high-throughput type screening” to easily modify polymeric materials toward commercially relevant targets. The combination of these developments will allow not only for the synthesis of polymeric materials capable of competing with commodity commercial polymeric materials but also for the development of more sustainable synthetic practices.

http://pubs.acs.org/doi/full/10.1021/acs.chemrev.5b00345