Determination of Thermodynamic Properties of Poly(4-tert-Butylstyrene) by Inverse Gas Chromatography

Some thermodynamic quantities were obtained for the interactions of poly (4-tert-butylstyrene) with alcohols, ketones, acetates, aromatics and alkanes by the inverse gas chromatography method in the temperature range of 343-463 K. The specific retention volumes (Vg°), the adsorption enthalpy of probes (ΔH2), the partial molar free energy of sorption (ΔG1S), the enthalpy of sorption (ΔH1S), the entropy of sorption (ΔS1S), the weight fraction activity coefficients of solute probes at infinite dilution (Ω1∞), and the Flory- Huggins thermodynamic interaction parameters (χ∞12) between polymer and solvents are given. The partial molar free energy (ΔG1∞, the partial molar heat of mixing (ΔH1∞ at infinite dilution and the solubility parameters of the polymer (δ2) were calculated. The solubility parameter of poly (4-tert-butyl- styrene) was determined from either the slope or intercept as 7.25 (cal/cm3)0,5 and 7.00 (cal/cm3)0,5 at 180°C, respectively.

THE THERMODYNAMIC PROPERTIES AND PHASE DIAGRAM OF THE GOLD–CADMIUM SYSTEM BY THE ISOPIESTIC METHOD

Activities of cadmium in gold alloys with up to 50 atom % Cd have been determined by an isopiestic method. The partial molar free energy, entropy, and heat of solution in the alpha and beta phases are calculated between 500 and 600 °C. The phase boundaries have been observed between 16 and 60 atom % above 400 °C. The boundaries of the two-phase regions α2 + β and β + δ′ are found at somewhat different concentrations than before, but the two-phase region α + α2 was not observed.

Thermodynamics of soil moisture.

The various equations used by several authors to express the partial molar free energy of soil moisture as a function of certain parameters were compared with a "parent" equation derived in this paper; certain basic differences of approach apparently lead to results which are identical only under certain conditions; from the parent equation, equations with practical applicability are derived. The methods available for the experimental determination of the partial molar free energy of soil moisture are reviewed with special reference to the assumptions underlying the application of the freezing-point depression of soil moisture. (Abstract retrieved from CAB Abstracts by CABI’s permission)