STRUCTURES AND MECHANICAL-PROPERTIES OF CELLULOSE FILAMENT SPUN FROM CELLULOSE AQUEOUS NAOH SOLUTION SYSTEM/

An attempt was made to disclose super-molecular structure and mechanic al properties of new cellulose filament prepared from cellulose-aqueou s alkali solution system. X-Ray crystallinity index chi(c)(X) of the n ew cellulose filament was far higher than those of other commercial ra yons, such as viscose including polynosic and cupro and was slightly l ower than the organic spun rayon. The new cellulose filament showed th e lowest degree of crystal orientation among these three kinds of cell ulose fibers, because of its lowest draft and stretching ratio during the spinning process. In the new filament degree of the intramolecular hydrogen bondings (1-chi(am)(C-3)) estimated by C-13 NMR method was h ighly developed. The mechanical loss tangent (tan delta) vs. temperatu re T curves of the new filament exhibited a relaxation (from higher te mperature side; alpha(2), alpha(sh)) attributed to micro-Brownian moti on of the cellulose chains, two beta(beta(a1), beta(a2)), local mode o f the chains, and gamma, rotational mode of primary alcohol group at C -6 position of pyranose rings, in the regions of T=250-100 degrees C a nd -30 similar to-100 degrees C, and near -100 degrees C, respectively . Judging from the co relationships of these relaxation peak temperatu re T-max to chi(c)(X) and 1-chi(am)(C-3), we concluded that there exis t two amorphous regions with well-developed intramolecular hydrogen bo nds but less advanced intermolecular hydrogen bonds and vice-versa in the new filament. The results of thermally stimulated currency (TSC) m easurements suggested that the hydrophobic interaction among cellulose chains is tightly formed in the region with the well-developed intram olecular hydrogen bonds. In this regard, chi(TSC) peak named here was found to correspond to mechanical relaxation alpha(sh). The tensile st rength and elongation of the new filament were comparable to those of the regular viscose rayon. The new filament showed less swelling ratio and low fibrillation nature in water. Woven fabrics made from the fil ament gave some softness and high abrasion, compared with other commer cial ones and were hard to wrinkle.