Modulated differential scanning calorimetry to study reacting polymer systems

Modulated (temperature) differential scanning calorimetry (MTDSC or MDSC) is used to study simultaneously the evolution of heat flow and heat capacity for the isothermal and non-isothermal reactions of polymer systems. An epoxy-anhydride thermosetting system is treated as an example. Vitrification and devitrtification steps are observed. The heat flow phase during isothermal and non-isothermal cure is always small, but its evolution contains information on relaxation phenomena, vitrification and devitrification, in the course of the chemical reaction. Modelling of the (heat flow related) chemical kinetics and the (heat capacity related) mobility restrictions contributes to a better understanding of the reaction mechanism and reaction kinetics up to a high degree of chemical conversion. The use of MTDSC as a tool for a quantitative construction of the vitrification curve in Temperature-Time-Transformation (TTT) and Continuous-Heating-Transformation (CHT) diagrams is illustrated.