Comparison of thermal and infrared spectroscopic analyses in the formation of polyurethane, unsaturated polyester, and their blends

Differential scanning calorimetry (DSC) and infrared spectroscopy (IR) are two widely used techniques for the measurement of polymerization kinetics. Reactions of several thermoset polymers: a polyurethane, two unsaturated polyester resins, and polyurethane‐polyester blends, were measured by these two methods. Results indicate that the thermal method is easy to use, and can generate both kinetic and thermal information. It is, however, less accurate and cannot detect detailed reaction mechanisms because the measurement relies upon the overall heat generation during reaction. Fourier transform infrared (FTIR) spectroscopy, on the other hand, can provide detailed kinetic information for multicomponent reactions such as styreneunsaturated polyester and polyurethane‐polyester blends. Data analysis, however, is more tedious and requires reliable calibration. For an accurate kinetic measurement, both methods should be used because the results from both experiments can calibrate each other.