A reaction order functional relationship with the Williams-Landel-Ferry equation in curing kinetics

A methodology is presented to obtain a kinetic model for curing reactions, from conversion against time and the glass-transition temperature versus conversion data. Isothermal runs for a cyanate ester resin from 140 to 190C, reported previously, were evaluated. The approach utilizes the conversion measurement time derivatives that allow following the estimated parameters' trends: the rate constant and the reaction order, in this case. An autocatalytic model was found, and the rate constants were truly constant along the experiments; thus, their Arrhenius parameters were evaluated. The methodology allowed constructing a master curve relating the variable reaction order with a temperature difference (reaction and glass transition) explained by the Williams-Landel-Ferry (WLF) equation. Four parameters describing the reaction order variation, two related to an exponential-like behavior and two required by the WLF equation, allowed describing the whole experimental set accurately. POLYM. ENG. SCI., 54:1900-1908, 2014. © 2013 Society of Plastics Engineers