Determination of dual glass transition temperatures of a PC/ABS blend using two TMA modes

• Published in: Journal of thermal analysis and calorimetry 2009-04, Vol.96 (1), p.7-14
• Main Authors: Yazdi, Mojtaba Haghighi, Lee-Sullivan, Pearl
• Format: Article
• Language: English
• Subjects: Analytical Chemistry; Applied sciences; Chemistry; Chemistry and Materials Science; Exact sciences and technology; Inorganic Chemistry; Measurement Science and Instrumentation; Organic polymers; Physical Chemistry; Physicochemistry of polymers; Polymer Sciences; Properties and characterization; Thermal and thermodynamic properties
• ISSN: 1388-6150; 1588-2926; 1572-8943
• DOI: 10.1007/s10973-008-9831-3

An inherent challenge with polymer blends is the difficulty in resolving the glass transition, T g , for the smaller mass fraction component. The objective of this work was to determine the practical scanning conditions for identifying the dual T g ’s for a 75:25 polycarbonate/acrylonitrile-butadiene-styrene (PC/ABS) blend using a thermomechanical analyzer (TMA). Scanning rates up to 20°C min −1 using dilatometer and expansion modes were studied. Heating and cooling rates were found to affect both T g values but the effects were not simple relationships. T g values could either increase or decrease depending on the scanning rate applied. Higher rates resulted in large thermal lags which opened the accuracy of measurements to question. Generally, higher rates tended to display only one T g but the duality of T g ’s can be detected with scanning rates between 0.5 and 5°C min −1 for both modes.