Cure Characteristics of a Vinyl Ester Resin as Assessed by FTIR and DSC Techniques

Thecuring kinetics of a vinyl ester (VE) resin has been investigated as a functionof curing temperature by using Fourier Transform infrared spectroscopy (FTIR)and differential scanning calorimetry (DSC). The curing reaction was monitoredby the decrease in double bond intensities for both VE and styrene (St). Thisallowed us to estimate the fractional conversion (degree of cure) by differentmethods. DSC was used to determine the overall degree of cure at differenttemperatures as well as the rate of the curing reaction. A good correlationbetween the degree of cure obtained by the two above techniques was observed inhigh temperature isothermal curing, in particular at 120°C. No complete curewas recorded by either FTIR or DSC. This was traced to the vitrificationphenomenon making the curing reaction diffusion controlled.