Chemical Hydrolysis and Surface Etching of Synthetic Fibers

Alkaline hydrolysis of polyester uses NaOH (10–200 g/L) at 80–100°C for 10–60 minutes to etch the fiber surface, creating micro-pits and increasing surface area by 20–40% with controlled weight loss of 5–20% owf to improve moisture wicking, hand, and dye affinity. Silk-like drape is achieved at 8–15% weight reduction. Nylon hydrolysis with HCl (5–10%) or NaOH increases carboxyl and amine end groups. PAN alkaline hydrolysis at 85–95°C introduces carboxylate groups, improving cationic dye affinity by 30–50%. Process generates high-COD alkaline effluent requiring neutralization.