Effect of acid and enzymatic treatments of TCF dissolving pulp on the properties of wet spun cellulosic fibres

Dissolving-grade softwood pulp was treated with EG-rich enzymes and hot diluted sulphuric acid, to decrease the molecular weight of cellulose. The treated samples were dissolved in aqueous sodium zincate and spun into cellulosic fibres by a wet spinning method. The effects of cellulose concentration in the spinning solution and of cellulose molecular weight on the fibre properties were studied. The molecular weight (M_w) of the treated cellulose decreased by 38 to 63%, depending on the treatment parameters. The falling ball viscosity of the alkaline solution prepared from the differently treated pulps correlated linearly with the M_w of the treated cellulose. At constant M_w of cellulose, the tenacity of the obtained wet spun fibres correlated positively with the cellulose concentration of the spinning solution. However, a higher cellulose concentration could not compensate the lowered M_w as to the fibre properties.