Fabrication of regenerated cellulose fibers using phosphoric acid with hydrogen peroxide treated wheat straw in a DMAc/LiCl solvent system

Regenerated cellulose fibers (RCFs) are widely used biodegradable and eco-friendly materials made from woody biomass that can replace synthetic fibers. In this work, we explored the feasibility of fabricating RCFs using phosphoric acid with hydrogen peroxide (PHP)-treated wheat straw in an N, N-dimethylacetamide/lithium chloride (DMAc/LiCl) solvent system. The effects of upstream pretreatment conditions on the obtained cellulose-enriched fraction (CEF), the solubility of CEF in DMAc/LiCl, the mechanical properties of RCFs, and the interfacial interaction of residual lignin were systematically studied. CEF could be completely dissolved in DMAc/LiCl, and its wet spun RCFs had tensile strengths of 184 MPa and toughness values of 25 MJ/m3; it demonstrated remarkable wet strength (84 MPa), wet toughness (11 MJ/m3), and dyeing properties. The existence of residual lignin negatively affected the RCF mechanical properties; however, it enhanced its resistance to water infiltration. The present work provided a new approach for producing RCFs from woody biomass.