At 315 C isocyanic acid can be still detected. The released gases are mainly due to methacrylic acid. At 353 C methanol occurs in the gas phase. Isocyanic acid and methacrylic acid are still present. The release of methacrylic acid cannot be observed in the DSC curve.
Isocyanic acid is released during the exothermal curing reaction.
Methacrylic acid evolves during the two-step decomposition of the powder coating and is accompanied by the release of carbon dioxide. The decomposition product methanol is detected between the 300 C and 430 C. Figure 10. TG, DTG and DSC curve in comparison with the traces of the detected methacrylic and isocyanic acid. Summary The DSC method allows the description of powder coating systems. The glass transition and the exothermal curing reaction as well as the degree of cross-linking can be determined.