Abstract:

In order to improve the solubility of hemp fibers, samples were subjected to alkali pretreatment and lithium chloride /N, N- Dimethylacetamide (LiCl/DMAc) solution treatment. Native hemp fibers were immersed in 18% alkali liquor and 60℃ bath temperature for 1 -4 h. After pretreatment, hemp fibers were dissolved in 10% LiCl/DMAc solvent system at different temperatures (70 C, 80 C and 95 C).The changes of the surface morphology, crystallization structure and solubility of hemp fibers were indicated by scanning electron microscope, Fourier transform infrared spectroscopy, X-ray diffraction and solubility test. The results show that with the alkali treatment crystal form of cellulose I turned into cellulose II . Solubility of hemp fibers increased when LiCl/DMAc treatment temperature were raised from 70℃ to 95℃. After alkaline activation, hemp fibers could be dissolved1.0-1.2g for 2h and 1.2-1.5g for 3h in 10% LiCl/DMAc soluble system. The viscosity value of the hemp/LiCl/DMAc with hemp fiber pretreated by NaOH for 3 h is greater for 3 h NaOH preteratment hemp fibers in. The solution of hemp/LiCl/DMAc is stable.

Key words: hemp cellulose, sodium hydroxide, LiCl/DMAc system, solubility