Thermodynamic properties of polystyrene and styrene

Abstract

A Tarassov function has been used to estimate the specific heat of polystyrene between 0° and 60°K. 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. The entropy of polymerization of styrene at 298.16°K. was found to be 26.69 cal./mole°.The thermodynamic function Cp/T versus T as calculated for polystyrene, increases to a maximum at 65°K. and then increases again at the glass transition temperature. The Tarassov function, which is shown to be useful in estimating the specific heat of amorphous polymers, should be combined with a T3 Debye function to yield more accurate cv data at low temperatures. The number of classically vibrating units per repeating unit of polystyrene was found to be 6.57. The difference Cp – Cv was calculated at 273°K. and found to be 2.0 cal./mole°.

Two Empirical Corresponding States Relationships for the Ratio of the Heat Capacities of Polymers

“…As can be seen, equation (4) reproduces the exper1mental data to w•thin an average deviation of 1.5%.…”

“…We have fitted the plotted points in Figure 1, by the method of least squares, to an equation of the type C/Cv -a + bg (I) +cg (4) where a = 1.0000, b --0.0449, and c -0.1036. As can be seen, equation (4) reproduces the exper1mental data to w•thin an average deviation of 1.5%.…”

Polymer microring resonators for high-sensitivity and wideband photoacoustic imaging

“…We used this equation to estimate the expected peak pressure level to be 77.6 Pa in the imaging experiment presented in Section III-A with c = 2380 m/s [23], β = 210 × 10 −6 K −1 [24], and C p = 1.3 kJ/kg/K [25] for PS, R = 24.5 μm, r = 5 mm, and W = (0.35 mJ/cm 2 ) × πR 2 /(4 πR 3 /3) = 107 mJ/cm 3 assuming complete and uniform absorption in the bead. The NEP of microring devices was estimated by the applied peak pressure divided by the optical signal-to-noise ratio (SNR).…”

Heat capacity and thermodynamic functions of polyvinyl alcohol

“…1 are of considerable interest. The thermodynamic functions, which were calculated by standard relationships, (3,4) are presented in table 1 and 6xhibit similar changes with temperature as do the functions of polystyrene (3), polyethylene (4) and polymethyl methacrylate (7). The thermodynamic functions, which were calculated by standard relationships, (3,4) are presented in table 1 and 6xhibit similar changes with temperature as do the functions of polystyrene (3), polyethylene (4) and polymethyl methacrylate (7).…”

“…1 the Cp of PVA increase linearly with temperature. Previous studies (3,4,5) have indicated that the use of a Tarassovfunction at low temperature will introduce little error into the calculated values of the thermodynamic functionS. The heat capacity between 10 c and 58 °K was estimated by means of a single parameter Tarassov function (3,5) with 0T equal to 278 °K.…”