IR spectroscopy based thermal analysis of polymers

Simple mid-infrared spectroscopy based methods for obtaining complete thermal characterization of polymers are proposed. In addition to some previously described structural transformations, such as melting and thermal decomposition, the proposed IR (transmittance and attenuated total reflectance) based thermal analyses can also determine glass transition temperatures. This innovative approach is extremely significant since the glass transition does not produce any vibrational band changes and is, therefore, completely undetectable by traditionally employed IR spectroscopy. The methods can be conducted with small amount of sample (approximately 1 mg) and with heating rates equivalent to those in DSC measurements. The method's efficiency was corroborated by measuring the thermal transformations of various model polymers. Identification of glass transition, as well as other physical and chemical processes, obtained in a rapid and economical manner clearly demonstrates that IR spectroscopy can provide reliable and self-sufficient thermal characterization of polymers for analytical and quality control purposes.