High Tensile Strength Regenerated α-1,3-Glucan Fiber and Crystal Transition

alpha-1,3-Glucan is a linear and crystalline polysaccharide which is synthesized by in vitro enzymatic polymerization from sucrose. A previous study reported that regenerated fibers of alpha-1,3-glucan were prepared using a wet-spinning method. However, the mechanical properties were poorer than cellulose regenerated fibers. Then, in this study, the mechanical properties of the regenerated alpha-1,3-glucan fiber were improved by the transformation of the crystal structure and stretching. The regenerated fiber stretched in water and dehydrated by heating showed high tensile strength (18 cN/tex) that is comparable with that of viscose rayon. Moreover, the crystal structures of the regenerated fibers were investigated using wide-angle X-ray diffraction (WAXD). To date, four crystal polymorphs of alpha-1,3glucan from polymorph I to IV have been reported. This study revealed that the regenerated alpha-1,3-glucan fibers had two different polymorphs, polymorph II (hydrated form) and polymorph III (anhydrous form), depending on post-treatment methods of stretching and annealing procedures. Furthermore, the obtained distinctive 2D-WAXD patterns suggested that polymorph III is identical to polymorph IV.

Automated summary

The mechanical properties of regenerated alpha-1,3-glucan fiber were improved by transforming the crystal structure and stretching methods, resulting in comparable tensile strength with viscose rayon. Two different crystal polymorphs, polymorph II and polymorph III, were identified in the regenerated fibers depending on post-treatment methods. Additionally, the study revealed that polymorph III is identical to polymorph IV based on distinctive 2D-WAXD patterns.