Cotton yarn mercerization

Cotton yarn mercerization is a process which cotton yarns react with sodium hydroxide solution under tension condition. The process is heterogeneous non-catalytic reaction. The main objects of this work are to determine the rate of mercerization, the conversion of cotton fibres and the effective diffusivity of sodium ions in cotton fibre. The experiment were performed at the temperature between 303-343°K , concentration of sodium ions in mercerizing solution between 5.92 x 10⁻³ – 1.27 x 10⁻² gm-mole/ml., tension of cotton fibre between 112,380-337,130 gm/cm² and speed of stirrer between 80-750 rpm. Internal radius of cotton fibres were measured to be used in calculating rate of mercerization, percent conversion and effective diffusivity. The mathematical equations were developed by principle of expanding product-shrinking core model. From the results of experiment and analytical method, it was found that rate of mercerization is controlled by diffusion of sodium ions through the layer of alkali-cellulose. Equation of the rate of mercerization, the relation between time and conversion and effective diffusivity could be written respectively as shown below. [สูตร]