화학공학소재연구정보센터
Journal of Applied Polymer Science, Vol.67, No.5, 841-848, 1998
Heat capacity of polymer melts from the polymer chain-of-rotators equation of state
Recently, the chain-of-rotators equation of state derived from the rotational partition function was extended to polymers. Values of the three equation of state (EOS) parameters were obtained from fitting with experimental pressure-volume-temperature data and the parameters were correlated with the structure of the polymer repeat unit. In this article, the residual molar heat capacity derived from an EOS is added to the ideal gas heat capacity from Benson's group contribution method to obtain the polymer molar heat capacity at constant pressure, C-p. Predictions from the polymer chain-of-rotators (PCOR) using correlated parameters are compared with those obtained from PCOR, Sanchez-Lacombe, Flory-Orwoll-Vrij, and the perturbed-hard sphere chain equations of state using parameters fitted from experimental data. Deviations of calculated C-p from the formula of van Krevelen for liquid polymers are likewise presented. With the correlations developed for its parameters, the PCOR offers the advantage of predicting the C-p for polymer melts from just the knowledge of the polymer's structure.