Lignin-Based Polyurethane

Polyurethane(PU), one of the most multifunctional polymers, is produced by polyaddition reaction of polyols and isocyanates. It has found wild applications in coatings, elastomers, adhesives, foams. However, one of the problems related to the production of PU is its dependence on petroleum-based resources. With the consumption of petroleum resources and the destruction of environment, the searching for renewable raw materials has become a research hotspot. At present, most reports are based on biobased polyols replacing petroleum-based polyols to prepare polyurethane, among which vegetable oil and lignin are the most used. Lignin, a natural organic carbon resource with abundant reserves, is low value-added and wasted as fuel at present. Compared with vegetable oil, lignin does not compete with human for food and the performance of related products is superior. However, the utilization of lignin has some problems, such as isolation, heterogeneity, aggregation, steric hindrance and low activity. These disadvantages make the unmodified utilization and modified utilization of lignin become the key problem. This paper introduces the development status and latest research progress of lignin in bio-based polyurethane synthesis. Finally, the development prospects of lignin-based polyurethane materials in different fields are prospected.