Published online by Cambridge University Press: 27 November 2020
The moving die rheometer technique (MDR) is used to measure the elastic and viscous components of rubber. The analysis of the rheometry and the kinetic behavior can be used to obtain mathematical models to predict the viscosity of elastomers as a function of the temperature, the time and the degree of curing. These predictions allow the control, the optimization and the design of the process. In this research the phenomenological model of Kamal-Sourour was used to describe the curing kinetics, while the Carreau Macosko model was used to describe the viscous behavior of an ethylene - propylene diene industrial type compound (EPDM). The mathematical parameters for each model where determined by using non-linear regression techniques. Since the viscosity increases significantly while the curing rate decreases, we proposed a mathematical model based on the Carreau expression in order to consider the influence of the kinetic of curing in the apparent viscosity behavior. It was found that after the curing rate reaches its maximum the viscosity tends to infinity; that is, the chemical transition process known as fluidity point or gel point occurs in the vicinity of maximum curing rate. According to the results, it is concluded that rubber viscosity is well described by considering the curing variations; the fluidity point in the vulcanization process can also be obtained by the practical method of phenomenological approach.