Instrument reversing heat flow

FIGURE 31-14 Deconvoluted thermogram from an MDSC apparatus showing nonreversing and reversing heat flow components. (Courtesy of TA instruments. New Castle. DE.)... 

Table 5.1. Effect of experimental conditions on the reversing and non-reversing heat flows in the melt region. The sum of the heat flow signals is quantitative and is defined as the initial crystallinity of the quenched PET sample (courtesy of TA Instruments Inc.)...

Figure 2.89. The total heat flow, reversing heat flow, and the nonreversing heat flow from an MTDSC heating of quenched poly(ethylene terephthalate) (courtesy of TA Instruments).

Modulated temperature DSC has also been used to study plasticization of poly(ethylene terephthalate) by water. PET is somewhat hygroscopic and absorbs moisture, so the glass transition temperature will decrease. Quasi-isothermal analysis was used and the glass transition temperature was found to increase with time as the water evaporated (Toda et al. 1997d). A similar analysis was performed to investigate the effects of water on Nylon 6. A hermetically sealed pan was used and the plasticized glass transition separated into the reversing heat flow (TA Instruments 1994). 

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