Rate Reaction
Physical expansion rate of cotton cellulose when exposed to highly alkaline solutions governs the speed and thoroughness of the mercerization process. This phenomenon, which is described by fiber swelling kinetics, depends on both the concentration of the sodium hydroxide and the temperature of the bath. It determines the rate at which the crystalline structure of the cotton changes.
Structural Transition
Cotton fibers transition from a flat, bean-like cross section to a rounded, cylindrical form during this chemical reaction. Under the laws of fiber swelling kinetics, the maximum rate of swelling occurs at concentration levels between twelve and eighteen percent sodium hydroxide. The cellular walls expand as water is drawn into the crystalline regions, which increases the internal volume.
This structural change is irreversible after tension is applied and the caustic is washed away.
Process Duration
Fast reactions require only a few seconds of immersion to achieve the desired degree of structural change. Analyzing fiber swelling kinetics allows machine designers to calculate the optimal length of the dwell zone in continuous mercerizing ranges. If the fabric moves too quickly, the inner fiber core remains untreated.
This leads to poor luster and uneven dye uptake.
Quality Outcome
Slower swelling at higher temperatures can be compensated for by increasing the immersion time. In fiber swelling kinetics, temperature control is critical because warmer baths reduce the total swelling force. This reduction limits the luster of the processed yarn.
