THE FORMATION OF STRUCTURE IN THE SPINNING AND COAGULATION OF LYOCELLFIBERS

The formation of structure in the spinning of cellulose fibres from th e N-methylmorpholine-N-oxide (NMMO)/water system (Lyocell) has been st udied. The filament shape in the air gap was measured together with th e birefringence growth, using a special device built in our laboratory . The shape is consistent with what would be expected if the viscosity rises exponentially away from the spinneret. We have also shown that the birefringence is proportional to the stress. In the coagulation ba th, the precipitation is diffusion driven. Through this process, a hig hly fibrillar structure is obtained for lyocell fibres, which, as a re sult, has very good mechanical properties.