A Kinetic Model for Non-Oxidative Thermal Degradation of Nylon 66

A model is developed to predict rates of undesirable reactions in the low‐moisture, high‐temperature finishing stage of nylon 66 production. The model contains 56 unknown parameters and initial conditions, which are ranked based on their influence on model predictions, correlation with other parameters and uncertainty in their initial guesses. A mean‐square‐error criterion is used to determine that 43 of 56 parameters should be estimated. The proposed model, which describes the effect of melt‐phase water concentration on degradation, matches the data well with typical errors of 6.1 and 2.9%, respectively, for amine ends (A) and carboxyl ends (C) and 4.3, 27.2, and 29.4%, respectively, for evolution rates of CO2, NH3, and cyclopentanone (CPK). A model to predict the rates of undesirable reactions in low‐moisture, high‐temperature finishing stage of nylon 66 production is presented. Parameters are ranked based on their influence on model predictions, correlation with other parameters, and uncertainty in initial guesses. An MSE criterion is used to determine which parameters should be estimated to match end‐group and gas evolution data.