Solubility of bacteria cellulose in zinc chloride aqueous solutions

Bacterial cellulose (BC) was dissolved in zinc chloride aqueous solution (ZnCl2 center dot 3H(2)O) with a maximal concentration of 5.5 wt and regenerated bacteria cellulose (RBC) nascent fibers were spun with a wet-spinning process. The behavior of the BC/ZnCl2 center dot 3H(2)O solution was investigated, together with the structure and properties of the RBC nascent fibers. Results revealed that the BC/ZnCl(2 center dot)3H(2)O solution showed typical shear thinning behavior. Though there was no chemical reaction occurred during the dissolution and spinning process, crystal forms of the RBC were transformed from cellulose I to cellulose II. Compared with the original BC fibers, the RBC fibers had lower degree of crystallinity and thermal stability, and showed round brilliants along the fiber axis with surface cracks and fibrillation, which caused lower tensile strength of 0.66-0.83cN/dtex, and extension at break of 1.95-3.66%. (C) 2011 Elsevier Ltd. All rights reserved.