Cure characteristics of a vinyl ester resin as assessed by FTIR and DSC techniques

The curing kinetics of a vinyl ester (VE) resin has been investigated as a function of curing temperature by using Fourier Transform infrared spectros copy (FTIR) and differential scanning calorimetry (DSC). The curing reactio n was monitored by the decrease in double bond intensities for both VE and styrene (St). This allowed us to estimate the fractional conversion (degree of cure) by different methods. DSC was used to determine the overall degre e of cure at different temperatures as well as the rate of the curing react ion. A good correlation between the degree of cure obtained by the two abov e techniques was observed in high temperature isothermal curing, in particu lar at 120 degreesC. No complete cure was recorded by either FTIR or DSC. T his was traced to the vitrification phenomenon making the curing reaction d iffusion controlled.