Application of Lignins in Formulation and Manufacturing Bio- Based Polyurethanes by 31P NMR Spectroscopy

Abstract

The application of several industrial and technical biomass lignins from forestry and agricultural residues extracted by different chemical pulping processes in view of biobased polyurethanes were studied. Several qualitative and quantitative methods were utilized to characterize and elucidate lignin profiles by evaluating their physical and chemical properties as a potential substitute for petroleum-based polyols. The morphology, molecular weight distributions, elemental compositions, glass transition temperature and several important functional groups containing hydroxyl units were classified and their contents were determined quantitatively. In this chapter, lignin substitution in polyurethane by (i) direct substitution, (ii) with combination of polyols or (iii) chemically modified was reviewed. The emerging information aims at addressing a number of pressing issues relevant to the scientific development for value-added applications from lignins during industrial production of biofoams.

Optimizing Hardwood Lignin Precipitation from Kraft Black Liquor: A Study of Temperature and pH Effects

“…The abundance of aliphatic hydroxyl groups in lignin enhances its solubility in diols, benefiting the delignification in biomass fractionation [64]. In polyurethane production, a higher hydroxyl concentration modifies the cure rates, adds rigidity, and improves the cross-linking [65]. For the biocatalysis of carbohydrates, the selective acylation of lignin's hydroxyl groups is key [50].…”