Investigating the Sensitivity of Thermal Analysis Methods to Glass Transition

Abstract

To determine the glass transition temperature Tg of amorphous polymers, five thermal analysis methods are used: differential scanning calorimetry (DSC), modulated DSC (MDSC(tm)), thermomechanical analysis (TMA), dynamic mechanical analysis (DMA), and dielectric analysis (DA). In each of these types of analysis, the Tg is determined from the change in one of the properties of the substance during glass transition. Therefore, the relative sensitivity of the different methods to determination of Tg depends greatly on the nature of the substance under investigation, and also on the experimental conditions, e.g. the heating rate. In the present investigation, data on the glass transition temperature of a standard amorphous thermoplastic that were obtained by the five conventional thermal analysis methods are compared. The results obtained reflect the types of problem that may arise. The experimental data set out below were obtained on TA Instruments series Q instruments ( www.intertech-corp.ru ).