Prediction of gel-time in the cure of unsaturated polyester resins: mechanistic and statistical analyses

In this work the gel time is described as a function of the radical concentration. Gelation is assumed to occur when the radical concentration reaches a critical value. A simple gelation model based on the initiation step only is proposed, which can be used to predict the gel time of a free radical crosslinking polymerization. A more complicated gelation model, including initiation, inhibition and propagation steps, is also presented. The applicability of these models is compared to that of a statistical analysis based on the 2-level factorial design.