The kinetics of hydrolytic polymerization of ϵ-caprolactam

• Published in: Journal of applied polymer science 1979-07, Vol.24 (1), p.211-224
• Main Authors: Tai, Kazuo, Teranishi, Hiroichi, Arai, Yoshihiro, Tagawa, Takashi
• Format: Article
• Language: English
• ISSN: 0021-8995; 1097-4628
• DOI: 10.1002/app.1979.070240119

A method to determine the concentration of ϵ‐aminocaproic acid (ACA) in poly‐ϵ‐caprolactam by high‐pressure liquid chromatography is established. The polymerizations for initial water concentrations of 0.42, 0.82, and 1.18 mol/kg and temperatures of 230, 240, 250, 260, 270, and 280°C were performed and concentration‐versus‐time curves were obtained for ACA, ϵ‐caprolactam (CL), and endgroups (EG). Each curve for ACA and EG has a maximum which increases monotonically in its value and shifts from right to left in position with increasing either the temperature or the initial water concentration. The reaction rates of CL, EG, and ACA were also evaluated numerically from the concentration data. The observed kinetic data were compared with those obtained by the numerical solution of the rate equations with Reimschuessel's kinetic constants. Good agreement is found in CL and EG concentrations but discrepancies in ACA concentration and rates are considerable, particularly in the early stage of the polymerization.