Kinetics of the crosslinking reaction of nonionic polyol dispersion from terpene-maleic ester-type epoxy resin

摘要

The bulk crosslinking reaction kinetics of a novel two-component waterborne polyurethanes (2K-WPUs) composed of a bio-resin-based polyol dispersion and a hydrophilically modified hexamethylene diisocyanate tripolymer are investigated by freeze-drying and differential scanning calorimetry (DSC) technique at different heating rates. The data fit for the above two components is implemented with the nth-order kinetics equation and Málek's mechanism function method, respectively. The kinetic parameters of crosslinking reaction are determined by the kinetic analysis of the data obtained from the thermal treatment, and then the kinetic model is built. The results indicate that the nth-order model deduced from Kissinger and Crane equation has great distinction with the experimental data, while the Málek analytic mechanism shows that the crosslinking process of the crosslinking reaction follows an autocatalytic reaction. The two-parameter (m and n) autocatalytic model (S-B model) can well describe the crosslinking reaction process of the studied 2K-WPU. The DSC curves derived from the experimental data show a good agreement with the theoretical calculation under 5-20 C min~(-1) heating rate. The results provide theoretical basis for the choice of the manufacturing process and the optimization of processing window.