Melting of polymer crystals observed by temperature modulated d.s.c. and its kinetic modelling

Analysis of transitions of liquid crystals and conformationally disordered crystals by temperature-modulated calorimetry

“…17,18 In principle, the time scale of the temperature modulation of the TMDSC can be related to the scanning rate in a conventional DSC. Fast modulation corresponds to a high scanning rate.…”

Theory and Practice of Modulated Temperature Differential Scanning Calorimetry

“…Again, all of the signals can also be expressed as heat flows <dQ/dt> = average or total heat flow C pPCR β = phase-corrected reversing heat flow (21) <dQ/dt> -C pPCR β = phase-corrected non-reversing heat flow (22) C pK β = kinetic heat flow (23) Thus, in general, all signals can all equally well be expressed as heat capacities or heat flows simply by multiplying or dividing by the underlying heating rate β as appropriate. Often both types of signals are mixed, so reversing heat capacity is co-plotted with non-reversing heat flow.…”

“…7 it can be seen that the effects of the thermal resistances are smaller when helium is used and a reasonable compromise is 40 seconds (again with a calibration factor). While it is true that considerable progress has been made by some workers in characterising and compensating for these nonideal experimental conditions [12,[21][22][23][24][25] for most experimentalists, the best approach it to use longer periods that avoid the complications engendered by these thermal resistances. It should be noted that, if helium is used, the concentration of helium in the actual cell will generally not be 100% and will vary with flow rate.…”

“…equations 38 and 39 [23]. As in the above consideration of Arrhenius kinetics, the cyclic signal then takes the approximate form:…”

“…A more accurate consideration of the reversing heat capacity (still following the Arrhenius analysis, or again see Toda et al [23,25]) will give its variation with frequency (the difference C C pPCR − decreases as 2 / 1 ω for "large" frequency ω ).…”