The preparation and study of regenerated cellulose fibers by cellulose carbamate pathway.

In this work, using cotton pulps and urea as raw materials, cellulose carbamates (CCs) were successfully prepared by liquid-solid phase in the high-boiling aprotic and polar solvent (DMAc). Regenerated cellulose (RC) fibers were successfully spun from cellulose carbamate in a NaOH aqueous solution by wet spinning on a conventional viscose filament device. And the structures and properties of products were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffractometry (XRD), Thermal gravimetric analysis (TG) and Scanning electron microscopy (SEM), rheology measurement and dye testing. The results showed that the CC can be quickly dissolved in 9%NaOH solution. RC fibers exhibited a bright surface and an approximately circular cross section. There was no lobulate shape and contained obvious pores and voids in the internal sections. RC fibers demonstrated a typical cellulose II crystal structure and a good thermal stability. And tensile strength of the RC fibers was 1.4 cN/dtex, and their elongation at break was 6.8%. Furthermore, the RC fibers showed excellent dyeing properties compared with viscose rayon and Yingli Lyocell. So, the described carbamate pathway provided a simple and environmentally friendly method to overcome the environmental drawbacks of the traditional viscose process.