Kinetics of Polyester Fiber Dissolution

Abstract

A theoretical model has been developed to describe the kinetics of polyester fiber dissolution in alkaline solutions. The model is based on the surface reaction concept. The rate of dissolution is taken as being proportional to the surface area of fibers and to the concentration of OH^- ions raised to a certain power (order of reaction: 0, 1, or 2). Integrated forms of rate laws are derived for all possible orders of dissolution reactions. According to the results, weight loss is not a simple linear function of time, as usually accepted. The kinetics of the process is characterized by the rate constant, which is, for a given system, independent of the content of OH^-, fibers, and water in the system. The experiments performed with poly(ethylene terephthalate) and aqueous NaOH solution at 100°C show that the reaction is a first order process with respect to surface and hydroxyl ions. A practical application for silk-like fabric production is demonstrated. The temperature effect is considered on the basis of the activation energy. The proposed analysis of experimental data enables optimization of the tech nological process in which silk-like fabrics are produced by alkaline hydrolysis of polyester textiles.