Preparation of lignopolyols from wheat straw soda lignin
; Ahvazi, Behzad
; Wojciechowicz, Olivia
; Ton-That, Tan-Minh
NRC Biotechnology Research Institute; NRC Industrial Materials Institute; National Research Council Canada
Journal of Agricultural and Food Chemistry
wheat straw; soda lignin; oxyalkylation; propylene oxide; lignopolyl; characterization; 31P NMR spectroscopy; FTIR
Wheat straw soda lignin was modified and characterized by several qualitative and quantitative methods such as <sup>31</sup>P NMR spectroscopy, to evaluate its potential as a substitute for polyols in view of polyurethane applications. Chemical modification of the lignin was achieved with propylene oxide to form ligno-polyol derivatives. This was performed by a two-step reaction of lignin with maleic anhydride followed by propylene oxide and by direct oxyalkylation under acidic and alkaline conditions. The physical and chemical properties of ligno-polyols from each method and the subsequent chain-extended hydroxyl groups were evaluated. Direct oxyalkylation of lignin under alkaline conditions was found to be more efficient than acidic conditions and more effective than the two-step process for preparing ligno-polyol with higher aliphatic hydroxyl contents.