ETHYLENE-STYRENE COPOLYMERIZATION

The paper defines, the glass transition temperature (Tg) of elastomers using various thermal analysis techniques (differential scanning calorirnetry, DSC, derivative DSC; thermomechanical analysis. TMA, dynamic mechanical analysis, DMA. dielectric analysis, DEA; thermal stimulated current, TSC) and cumpares Tg values of eight elastomers by the first four techniques. Comparison of Tg by two TMA methods (expansion and penetration) is also included. Necessary information regarding both the specific technique and the sample used to compare published data is mentioned. Their inclusion, along with the Tg data, is emphasized. Correlation of Tg, as determined by thermal methods with that determined by an industrial low-temperature test method (ASTM D 1o53-89a) is discussed. The factors that are unique to elastomer Tg determination, such as subambient operation, as compared to other polymers, arc pointed out.