M. Pyda et al., Reversible and irreversible heat capacity of poly[carbonyl (ethylene-co-propylene)] by temperature-modulated calorimetry, J POL SC PP, 39(14), 2001, pp. 1565-1577
The heat capacity of poly[carbonyl(ethylene-co-propylene)] with 95 mol % C2
H4-CO- (Carilon EP (R)) was measured with standard differential scanning ca
lorimetry (DSC) and temperature-modulated DSC (TMDSC). The integral functio
ns of enthalpy, entropy, and free enthalpy were derived. With quasi-isother
mal TMDSC, the apparent reversing heat capacity was determined from 220 to
570 K, including the glass- and melting-transition regions. The vibrational
heat capacity of the solid and the heat capacity of the liquid served as b
aselines for the quantitative analysis. A small amount of apparent reversin
g latent heat was found in the melting range, just as for other polymers si
milarly analyzed. With an analysis of the heat-flow rates in the time domai
n, information was collected about latent heat contributions due to anneali
ng, melting, and crystallization. The latent heat decreased with time to an
even smaller but truly reversible latent heat contribution. The main melti
ng was fully irreversible. All contributions are discussed in the framework
of a suggested scheme of six physical contributions to the apparent heat c
apacity. (C) 2001 John Wiley & Sons, Inc.*