On the Elongation Mechanism of Regenerated Cellulose Fibres

Abstract

The elongation at break äs well äs the tensile modulus of solvent spun cellulose fibres, both measured in the conditioned state, correlate with the amorphous orientation factor. The relevant regression curves are similar to that of the relation between the elongation at break resp. the tensile modulus and the crystallite orientation factor; the latter preceding the amorphous orientation factor with increasing total orientation. Hence it is concluded, that the elongation mechanism of regenerated cellulose fibre does not consist only of orientation of crystallites, but that additionally a straightening and orientation of the less ordered molecular segments in the interstices between the crystallites has to be assumed.

Moisture sorption/desorption behavior of various manmade cellulosic fibers

“…The hydrophobic PES fiber showed an extremely low moisture uptake in comparison with that of the hydrophilic fibers. The moisture regain in Co fibers was distinctly lower than that in the regenerated cellulosics and W and D fibers because of the fewer amorphous regions in Co. 6 The total equilibrium moisture regain of D fibers was lower than that in regenerated cellulosics and W fibers at high RHs; this might be due to the internal structure of the D fibers. 7 The equilibrium moisture isotherms show a distinct hysteresis between the sorption and desorption cycles, indicating structural changes in the fibers caused by interaction with water.…”

Pilling in cellulosic fabrics, Part 2: A study on kinetics of pilling in alkali‐treated lyocell fabrics

“…2 In comparison with untreated lyocell fibers in wet state, the tenacity of alkali-treated fibers are almost stable and only slight variation was found among the different alkali concentrations as shown in Table I. The wet tensile strength of lyocell fibers shows positive correlation with the amorphous orientation.…”

“…At low concentrations study, sodium hydroxide decreased strength and modulus of lyocell fibers, but without changing the crystalline orientation significantly. 2 Along with an increasing concentration of the sodium hydroxide solution, a decrease of the amorphous orientation was recorded, whereas the crystalline orientation remains almost constant. 2 This could serve an explanation for the decrease in dry tenacity with higher sodium hydroxide concentrations.…”

“…The wet tensile strength of lyocell fibers shows positive correlation with the amorphous orientation. 2 Regarding to tenacity, the elongation at break of alkali-treated fibers decreased in both wet and dry state from $ 20 to 40% with increasing concentration of sodium hydroxide. At high sodium hydroxide concentrations, the low elongation made the fibers more rigid, less flexible, and easy to be pulled out from the yarn and fabric body.…”

“…As lyocell fiber is prone to fibrillation because of the extension of cellulose chains and alignment of fibers axis during spinning process, the physical properties of lyocell fibers are significantly changed in the swollen state. 1,2 The high potential of fibrillation in lyocell fabric has intensive correlation with crystallinity and intrinsic viscosity that define mechanical resistance of fabrics, for example, the high-fiber tenacity but low lateral cohesion. 1 In lyocell fabrics, the pill formation in the wet state is defined by swelling and fibrillation together with high friction as suggested in the mechanism of pilling.…”