Mercerization of Cotton

Mercerization treats cotton with 18–25% NaOH solution at 15–20°C under tension, causing fiber swelling of 15–20% in diameter and irreversible conversion from cellulose I to cellulose II crystal structure. Dye uptake increases by 25–30%, tensile strength by 10–20%, and luster improves significantly. Treatment duration is 3–5 minutes followed by thorough washing to pH 7. Cold mercerization below 15°C further enhances luster. Process adds $0.10–0.20/meter to fabric cost but commands 15–25% price premium in finished goods.