Thermal curing behavior of phenol formaldehyde resin-impregnated paper evaluated using DSC and dielectric analysis

This research article discusses composite panel manufacturers’ challenges in finding an optimum pressing time to achieve a trade-off between the panel’s performance and the production cost. Real-time cure monitoring techniques, such as dielectric analysis (DEA), have been developed to overcome the limitations of trial-and-error methods, which have been in use for a long time for the same purpose. DEA measures changes in the dielectric properties of the material during the cross-linking reactions in resin and provides necessary information for the cure state of the material. In this study, paper sensors based on interdigitated electrodes were employed to measure the curing behavior of phenol formaldehyde resin-impregnated paper. The paper sensors were found to be better than commercially available sensors in terms of compatibility, thinness, biodegradability, low cost, flexibility, and non-heterogeneity. The study compared the results obtained from DEA with those from differential scanning calorimetry (DSC) and found that DEA can be a good candidate for predicting curing behavior. The average enthalpy of the curing measured using DSC for the B-stage resin-impregnated PF resin was 35.28 J g−1. Moreover, it was observed from the rate of cure that at a higher temperature of 180 °C, the reaction follows an autocatalytic kinetic type as the reaction rate passes through a maximum. However, at lower temperatures, the autocatalytic reaction regime seems to be followed by a decelerating type. Further research on the effect of pressure and other parameters on the curing behavior of PF resin-impregnated paper can be done in the future.