The Property of Waterborne UV-curable Polyurethane Based on Alkali Lignin of Wheat Straw

To improve the added value of lignin, the modified alkali lignin of wheat straw was used to prepare waterborne UV-curable polyurethane. The purpose of this paper is to discuss the properties of the cured films made from the above lignin-based polyurethane. The mechanical and optical properties of the cured films were investigated. Results showed that the tensile storage modulus, tensile loss modulus, and tensile loss factor of the cured film were influenced by the addition of the lignin, which indicated that proper dosage of the lignin could change the micro-phase separation structure and improve the mechanical properties of the product. The addition of the lignin also influenced the gloss and light transmittance of the cured film. On the whole, the lignin-based polyurethane exhibits good mechanical and optical performance if proper proportion of the lignin was added to the product. The study was beneficial for utilizing the lignin in high value products.