Structure and Properties of Novel Cellulose Fibres Produced From NaOH/PEG-treated Cotton Linters

Aqueous mixture of NaOH/poly(ethylene glycol) (PEG) at a ratio of 9/1 was foundto be an excellent solvent for untreated cellulose. Na-Cellulose complex andhydration of the subsequent alkali ions are the key factors to the dissolutionmechanism. The role of PEG molecules is believed to be the acceptor of hydrogenbonding which connects the hydroxyl groups in cellulose and prevents the regenerationof cellulose through the inter- and intra-chains association. The formation of a highconcentration of spinning dope in NaOH/PEG aqueous solution provided an excellentpotential for formation cellulosic fibres with high mechanical properties. Novelcellulose multi-filament fibres were spun successfully, for the first time, from thecellulose-NaOH/PEG dope on a laboratory scale spinning machine. Coagulation wasaccomplished in a bath with H2SO4/Na2SO4 (10 / 5 wt%) aqueous solution. The tensilestrength, elongation-at-break, and crystallinity of the resulting fibres, in the given ordercorrespond to 1.94 cN/dtex, 5.72% and 54%. The morphology and structure of theregenerated fibres were characterized by different techniques, e.g., scanningelectron microscopy (SEM), nuclear magnetic resonance (13C NMR), wide-angle X-raydiffraction (WAXD), and Fourier transform infrared (FTIR) spectroscopy. The novelfibres possess circular cross-sections as well as relatively high molecular weights, andcrystallinity indexes comparable with cellulose II family crystal structure, leading togood mechanical properties. This new approach offers great potential for cellulosefibres on an industrial scale with a cheap, non-polluting and shorter production cyclecompared to that of viscose technology.