Recent advances in fabrication and application of lignocellulose-based polyurethane

The development of bio-based polyurethane (BPU) using renewable lignocellulosic biomass instead of petroleum-based raw materials has become an effective strategy to cope with resource shortage and environmental problems. However, few of lignocellulose-based polyurethane (LCPU) have been synthesized and used at industrial scales. As such, this review paper intends to provide insight into the recent advances in the fabrication and potential applications of LCPU and discuss the existing challenges. The strategies and synthesis pathways to prepare LCPU are summarized and discussed. The roles of lignin, cellulose, and hemicellulose as either fillers or bio-based polyols in the synthesis of BPUs are discussed in detail. The incorporation of lignocellulose component not only enhances mechanical property and thermal stability of PU but also endows PU with special characteristics such as antibacterial activity, self-healing, flame retardancy, and biodegradability. Discussion on the features or functions of the corresponding PU inherited from lignocellulose, the structure-function relationships and their potential applications are included. Moreover, the recent advance in the environmental sustainability and techno-economic feasibility of LCPU are summarized and explored. Finally, we offer perspectives on challenges and the future prospects of LCPU. This review will contribute to the further exploration of LCPU as sustainable materials.