Effects of Coagulation Conditions on Properties of Multifilament Fibers Based on Dissolution of Cellulose in NaOH/Urea Aqueous Solution

Abstract

Effects of coagulation temperature, coagulants, and wet-spinning methods on structure and properties of novel regenerated cellulose (RC) fibers prepared from cellulose in 7.5 wt % NaOH/11 wt % urea aqueous solution on pilot scale spinning machine by one- and two-stage coagulation were investigated by tensile testing, optical microscopy, scanning electron micrograph, and wide-angle X-ray diffraction. The results indicated that H2SO4/Na2SO4 and H2SO4 aqueous solutions are potential coagulants for NaOH/urea system and fibers wet-spun from the two-stage coagulation obviously exhibited the better mechanical properties than those from the one-stage coagulation. The optimal coagulation conditions for two-stage coagulation are 10 wt % H2SO4/15 wt % Na2SO4 for the first coagulation bath and 5 wt % H2SO4 for the second bath or 5 wt % H2SO4/15 wt % Na2SO4 for the first coagulation bath and 10 wt % H2SO4 for the second bath. Moreover, the tensile strength of novel fibers increased with a drop in coagulation temperature. The diffusion rate between the coagulant and solvent plays a major role in determining the mechanical properties of the cellulose fibers. Our spinning process was quite different from that of the viscose process, in which orientation and coagulation proceed more or less simultaneously. The production method of this fiber wet-spun could be suitable in the wide range of coagulation conditions, compared to the viscose one.

Magnetic Responsive Cellulose Nanocomposites and Their Applications

“…However, mechanical mixing magnetic fills into dissolved cellulose solution often results in an inhomogeneous dispersion of particles in the cellulose matrix, thus considerable attention has been paid to the in situ chemical synthesis of metal nanoparticles in polymer matrices. In our previous works, 7wt% NaOH/12wt% urea aqueous solvent at low temperature is used for cellulose dissolving, and regenerated cellulose fibers can be spun from this solution (Chen et al, 2006;Mao et al, 2008). The cellulose fiber at swollen state exhibits an interpenetrating macroporous structure with a mean pore diameter of about 150 nm.…”

Green and Economical Strategy for Spinning Robust Cellulose Filaments

“…Unfortunately, the low production of the nature fibers could not meet the market demand and the nonbiodegradable synthetic fibers would hurt the environment after being discarded. The regenerated cellulose multifilament, viscose rayon, as a mature commercial product has been developed for over 100 years owing to the good breathability, lustre, softness, drapability, and so forth. , However, the viscose procedure discharges the toxic CS 2 , waste water, and heavy metal, which would cause serious environmental problems . Therefore, many efforts have been devoted to developing new processing technologies for simplifying the complicated production route and avoiding the hazardous byproducts during the cellulose fiber production process using low-cost “green” chemical reagents and a simple wet-spinning process. − In the recent decades, a series of low-toxic and environmentally friendly cellulose solvent systems such as N -methylmorpholine- N -oxide (NMMO), cuprammonium solution, ionic liquids, and alkali/urea solutions have been developed for the cellulose fiber production. − Although some commercial products such as cuprammonium rayon (cuprammonium solution) and lyocell (NMMO) have been successfully developed from these solvents, the high requirements for the solvent recycle limit their large-scale production .…”

“…The regenerated cellulose multifilament, viscose rayon, as a mature commercial product has been developed for over 100 years owing to the good breathability, lustre, softness, drapability, and so forth. 3,4 However, the viscose procedure discharges the toxic CS 2 , waste water, and heavy metal, which would cause serious environmental problems. 5 Therefore, many efforts have been devoted to developing new processing technologies for simplifying the complicated production route and avoiding the hazardous byproducts during the cellulose fiber production process using low-cost "green" chemical reagents and a simple wet-spinning process.…”

Preparation and characterization of cellulose carbamate membrane with high strength and transparency

“…New dissolution systems and more severe conditions are needed. For example, a certain amount of cellulose 17–19 can be dissolved in alkali/urea solution system at low temperature, such as dissolving cotton pulp in 4.5 wt% LiOH/15 wt% urea aqueous solution (−12°C) to prepare 6 wt% cellulose solution, 20 and using 8 wt% LiOH·H 2 O/15 wt% urea aqueous solution precooled at −12.8°C to dissolve cellulose, a 4 wt% cellulose solution 21 can be obtained. The cellulose pulp can be dispersed in NaOH/urea aqueous solution.…”