The Extrapolation Method for Hyper Differential Scanning Calorimetry

In order to eliminate the temperature lag effect and obtain the accurate temperature results from hyper differential scanning calorimetry (Hyper-DSC) operated at high heating rate, an adjustable method, namely “Extrapolation Method”, had been introduced by us in former papers. And in this paper, we wanted to support the accuracy of this method by other instruments. Specifically, the extrapolated glass transition temperatures (Tg, 61.5 °C) of PLA film, which was obtained by Hyper-DSC, was close to the value detected directly by normal DSC (62.0 °C). And the extrapolated Tg of waxy starch film (59.7 °C for 8.7% moisture content, and 57.2 °C for 11.2% moisture content) was close to the values detected by modulated temperature DSC (MT-DSC) (63.6 °C and 56.8 °C correspondingly). Consequently, these experimental results support that the “Extrapolation Method” is a feasible way to eliminate temperature lag effect for Hyper-DSC.

Thermal Relaxations of Polymers Revealed by Reversing and Non-Reversing Coefficient of Thermal Expansion

Reversible and irreversible events can be resolved) using modulated temperature DSC and TMA. Each technique has advantages, those for TMA include longer times and slower scan rates that allow greater approach to material equilibrium. The thermal expansion coefficient and glass transition temperature can be isolated from relaxations and structural changes. Modulated temperature thermomechanometry (mT-TM) is used to characterize amorphous thermoplastics including PS, PMMA, PC and PPO, and the results including annealing, heating and cooling.