Engineering plastics from lignin. XV. Polyurethane films from chain‐extended hydroxypropyl lignin

作者：Stephen S. Kelley, Wolfgang G. Glasser, Thomas Carl Ward · 发表于：Journal of Applied Polymer Science · 年份：1988 · DOI：10.1002/app.1988.070360403 · 被引用次数：39 · 研究领域：Lignin and Wood Chemistry、Polymer composites and self-healing、Wood Treatment and Properties

Abstract A series of polyurethane (PU) films was prepared from chain‐extended hydroxypropyl lignins (CEHPL). In appearance, these films ranged from brittle and dark brown to rubbery and bronze. The thermal, mechanical, and network properties of these PUs were investigated by DMTA and DSC analysis. All films exhibited single Tg's which varied between −53° and 101°C, depending on lignin content. From swelling experiments, molecular weight between crosslinks (Mc) was determined and found to vary over 2.5 orders of magnitude. The Mc's were related to the change in Tg that accompanied network formation. Stress–strain experiments showed a variation in Young's modulus between 7 and 1300 MPa. Most of the variation in material properties was related to lignin content and to a lesser extent to diisocyanate type, hexamethylene diisocyanate, or toluene diisocyanate. The source of the CEHPL had no effect on the observed properties. From these results it was concluded that the properties of PUs can be controlled and engineered for a wide variety of practical uses.