Chemorheological study of a polyfurfuryl alcohol resin system—Pre-gel curing stage

Abstract

The rheological and chemorheological behavior of a new biomass-based polyfurfuryl alcohol (FA) resin aimed to be used as a matrix in composite materials is studied in this work. The viscosity dependence on the shear rate and temperature of the resin is studied under steady and oscillatory conditions. The FA resin exhibits a Newtonian flow behavior within the shear rate range tested. The dependence of the viscosity of the uncured resin on temperature is measured and modeled. The flow activation energy, as calculated by the Arrhenius model, is 63.3kJmol−1. The chemorheological study of the curing process showed that the flow activation energy of the resin is increased when the amount of catalyst is increased. Furthermore, the curing parameters of the FA resin using three amounts of catalyst of 2, 4, and 6% (w/w), are obtained by the Arrhenius model. The curing activation energy is found to be about 96kJmol−1 and with no dependence on the amount of catalyst. However, a significant difference of the logarithm of the pre-exponential curing parameter is found. This parameter increases from 28.9 to 30.7 when the amount of catalyst is increased from 2 to 6% (w/w). Based on the established values of the Arrhenius model parameters, predictions are made for the evolution of viscosity of the resin during isothermal curing with different temperatures, and different amounts of catalyst. This is of great importance in the design of the curing processes of the FA resin during development and improvement of composite manufacturing processes.