Accession Number : AD0252578

Title :   THERMODYNAMIC PROPERTIES OF POLYSTYRENE AND STYRENE

Corporate Author : NAVAL ORDNANCE LAB WHITE OAK MD

Personal Author(s) : WARFIELD,R.W. ; PETREE,M.C.

Report Date : FEB 1961

Pagination or Media Count : 25

Abstract : A Tarassov function has been used to estimate the specific heat of polystyrene between 0 and 60 K and these data, together with published Cp data, have been used to calculate the entropy, enthalpy, and free energy of styrene and polystyrene from 0 to 298.16 K. Entropy of polymerization of styrene at 298.16 K was found to be 26.69 cal/deg. mole. Changes in the various thermodynamic functions at the glass transition temperature, Tg, are in accordance with the second order transition as defined by Ehrenfest. The thermodynamic function Cp/T vs T as calculated for polystyrene increases to a maximum at 65 K and then increases agin at the glass transition temperature. An approximation is made of the heat capacity at constant pressure per vibrating unit of polystyrene at 273 K. Cp-Cv is calculated at 273 K and found to be 0.019 cal/deg. gm. or 1.98 cal/deg. mole. (Author)

Descriptors :   *POLYMERIZATION, *POLYMERS, *STYRENES, ENTHALPY, ENTROPY, ETHYLENES, THEORY, THERMODYNAMICS, TRANSITION TEMPERATURE

Distribution Statement : APPROVED FOR PUBLIC RELEASE