Partial Molar Heat Of Mixing Research Articles

Heat of mixing profile, complexation curve and spectroscopic investigation of binary mixtures containing bicyclic Brønsted superbase DBN with hydrogen ethanoate

Isothermal titration calorimetry (ITC) experiments were performed for investigation of binary mixtures comprised of the Brønsted superbase DBN with hydrogen ethanoate (AcOH). The heat of mixing (HE) profile was recorded at (343.15 ± 0.1) K and fitted with a 5-parameter Redlich-Kister (RK) polynomial. RK fit parameters were subsequently used to quantify partial molar heats of mixing, xiHiE, for each component i. ITC-based complexometric titration data for the binary mixtures were recorded separately in methyl isobutyl ketone (mibk) and dodecane, to investigate the energetics of non-random clustering phenomena. Variable temperature 1H-NMR in combination with ATR-FTIR spectroscopic analyses were employed in parallel for elucidation and verification of liquid state ion speciation. These investigations reveal a strongly non-ideal system, and indicate “superbase” character of DBN is preserved for specific compositions where stoichiometric ionic liquids (ILs) form. Available ion speciation has been found to include [DBN-H]+, [AcO]− as well as μ2-hydrogen-bridged, hydrogen-bonded homoassociate anions, of the type [H(OAc)2]−, with double liquid salt formation characterising various compositions based on spectroscopic determinations.

Thermodynamic studies on tert-amine modified polystyrene based polymer/solvent systems by inverse gas chromatography method

In the present work, vinyl benzyl chloride (VBC) was polymerized by using free radical polymerization. The obtained PVBC was reacted with dibutyl amine to obtain tertiary amine modified polystyrene based polymer (PVBC-Dibutyl amine). The inverse gas chromatography (IGC) method was used to examine the thermodynamic properties of the polymer. Firstly, the retention diagrams of some polar and non-polar solvents on PVBC-Dibutyl amine were obtained over a temperature range from 135 to 160° C. Then, the thermodynamic parameters, including Flory–Huggins interaction parameter, weight fraction activity coefficient, partial molar heat of sorption, and partial molar heat of mixing were determined via interactions between the polymer and selected solvents at infinite dilution. The results reveal that the alkanes are poor solvents for the polymer whereas n-butyl acetate, i-butyl acetate, ethyl acetate, n-propylbenzene, i-propylbenzene, and ethylbenzene are moderately solvents in the studied temperature range.

Phase equilibria and thermodynamic description of solid dispersions of 8-hydroxyquinoline – 4-chlorobenzoic acid drug system

In present article 8-hydroxyquinoline (HQ)-4-chlorobenzoic acid (CBA) binary drug system has been undertaken to study phase diagram and thermodynamic contribution in the system in terms of partial and integral mixing and excess functions. The phase equilibria of the system undertaken shows the formation of 1:1 addition compound C and its eutectic E at 214º and199º c respectively. The negative value of molar free energy of mixing (∆GM) of solid dispersion at 0.810 and 0.895 mole fraction of CBA suggests that the mixing in these cases is spontaneous. The integral molar enthalpy of mixing value corresponds to the value of excess integral molar free energy of the system favors the regularity in the binary solutions. The positive value of excess free energy (gE) for all the eutectic and noneutectic solid dispersion suggests an association of weaker nature between unlike molecules and of stronger nature between like molecules. Gibbs-Duhem equation gives the graphical solution of partial molar heat of mixing (Hi-M), activity and activity coefficient of a particular constituent in the binary mix. Interfacial roughness of the binary solid dispersion has also been explained. Keywords: Binary drug dispersion, phase diagram, activity, activity coefficient, mixing and excess function.

Thermodynamic and surface characterisation of 4-[4-((S)-citronellyloxy)benzoyloxy]benzoic acid thermotropic liquid crystal

ABSTRACTThe inverse gas chromatography (IGC) method was used to obtain thermodynamic and surface properties of the thermotropic liquid crystalline material, 4-[4-((S)-citronellyloxy)benzoyloxy]benzoic acid (CBB). Liquid crystal (LC) selectivity was investigated using the alcohol and acetate isomers by the IGC method at temperatures between 338.2 K and 463.2 K. The retention diagrams of n-decane, undecane, dodecane, tridecane, n-butyl acetate, iso-butyl acetate, ethylbenzene and chlorobenzene on CBB were plotted in the temperature range between 468.2 K and 493.2 K. The specific retention volume, , Flory–Huggins interaction parameter, , equation-of-state interaction parameter, , the partial molar heat of sorption, , the partial molar heat of mixing, , the molar heat of vaporization, and the weight fraction activity coefficient, , were determined.The dispersive component of the surface free energy, , of the studied adsorbent surface was estimated in the infinite dilution region. The specific free energy of adsorption, , the enthalpy of adsorption, and the entropy of adsorption, , of solvents on LC were determined. The values of were correlated with the donor and the acceptor numbers of the probes to quantify the acidic and the basic parameters of the LC surface. The values obtained for and parameters indicated an acidic character for the surface of CBB.

Determination of thermodynamic interactions of poly(l-lactide) and biphasic calcium phosphate/poly(l-lactide) composite by inverse gas chromatography at infinite dilution

Inverse gas chromatography at infinite dilution was applied to determine the thermodynamic interactions of poly(l-lactide) (PLLA) and the composite of biphasic calcium phosphate and PLLA (BCP/PLLA). The specific retention volumes, $$ V_{\text{g}}^{0} $$ , of 11 organic compounds of different chemical nature and polarity (non-polar, donor or acceptor) were determined in the temperature range of 308–378 K for PLLA and 308–398 K for BCP/PLLA. The weight fraction activity coefficients of test sorbates, $$ \Omega_{1}^{\infty } $$ , and the Flory–Huggins interaction parameters, $$ \chi_{12}^{\infty } $$ , were estimated and discussed in terms of interactions of the sorbates with PLLA and BCP/PLLA. Also, the partial molar free energy, $$ \Delta G_{1}^{\infty } $$ , the partial molar heat of mixing, $$ \Delta H_{1}^{\infty } $$ , the sorption molar free energy, $$ \Delta G_{1}^{\text{S}} $$ , the sorption enthalpy, $$ \Delta H_{1}^{\text{S}} $$ , and the sorption entropy, $$ \Delta S_{1}^{\text{S}} $$ , were analyzed. A different chromatographic behavior of the two investigated samples, PLLA and BCP/PLLA, was observed. The values of $$ \Omega_{1}^{\infty } $$ indicated n-alkanes, diethyl ether, tetrahydrofurane (THF), cyclohexane, benzene, dioxane (except for 338 K), and ethyl acetate (EtAc) (except for 338 K) as non-solvents, and chloroform (CHCl3) as good solvent (except for 378 K) for PLLA. For BCP/PLLA, CHCl3, EtAc (for 378 K), dioxane (except for 378 K), and THF were indicated as good solvents.

Determination of the solubility parameter of ionic liquid 1-octyl-3-methylimidazolium hexafluorophosphate by inverse gas chromatography

The thermodynamic and physicochemical properties of 1-octyl-3-methylimidazolium hexafluorophosphate ([OMIM]PF6) were investigated by inverse gas chromatography from 343.15K to 373.15K. Two groups of solvents with different chemical natures and polarities were used to characterize [OMIM]PF6–solvent interactions. The specific retention volume, molar heat of sorption, weight fraction activity coefficient, partial molar heat of mixing, Flory–Huggins interaction parameter between [OMIM]PF6 and the tested solvents, as well as activity coefficients at infinite dilution were determined. The solubility parameters of [OMIM]PF6 were also determined by plotting the graph of δ12/(RT)−χ12∞/V1 versus the solubility parameter δ1 of the probes.

Determination of the solubility parameter of ionic liquid 1-allyl-3-methylimidazolium chloride by inverse gas chromatography

Some thermodynamic quantities were obtained for the interactions of ionic liquid 1-allyl-3-methylimidazolium chloride ([AMIM]Cl), with n-hexane (n-C6), n-heptane (n-C7), n-octane (n-C8), n-nonane (n-C9), chloroform, ethyl acetate, ether and acetone by the inverse gas chromatography (IGC) method in various temperatures. The thermodynamic parameters including the molar heat of sorption, weight fraction activity coefficient, Flory–Huggins interaction parameter and partial molar heat of mixing were calculated to judge the interactions between [AMIM]Cl and solvents at the studied temperatures. Also, the solubility parameter of [AMIM]Cl was found by plotting the graph of solubility parameters of probes. The results showed that the selected solvents n-C6, n-C7, n-C8, n-C9, ethyl acetate, ether and acetone were poor solvents for [AMIM]Cl, while chloroform was a favorite solvent for [AMIM]Cl. The solubility parameter of [AMIM]Cl was calculated to be 23.33 (J·cm−3)0.5 (343.15K), 22.57 (J·cm−3)0.5 (353.15K), 21.63 (J·cm−3)0.5 (363.15K), and 20.88 (J·cm−3)0.5 (373.15K) by IGC.

Determination of the Solubility Parameter of Ionic Liquid 1-Hexyl-3-methylimidazolium Hexafluorophosphate by Inverse Gas Chromatography

In this study, physical and thermodynamic properties of 1-hexyl-3-methylimidazolium hexafluorophosphate ([HMIM]PF6) were investigated by using inverse gas chromatography (IGC). Two groups of solvents with different chemical natures and polarities were used to obtain information about [HMIM]PF6-solvent interactions: chloroform, ethyl acetate, ether, acetone and alkanes. The specific retention volume (Vg0), molar heat of sorption, weight fraction activity coefficient, activity coefficients at infinite dilution, partial molar heat of mixing and Flory–Huggins interaction parameter between [HMIM]PF6 and solvents were determined in the temperature range of 343.15–373.15 K. Also, the solubility parameters of [HMIM]PF6 at infinite dilution were found by plotting the graph of δ12/(RT) – χ1.2∞/V1 versus solubility parameters, δ1, of probes. The results showed that n-C6, n-C7, n-C8, n-C9, ether, and n-butyl alcohol were poor solvents for [HMIM]PF6; chloroform, acetone, and ethyl acetate were favorite ones, while ethanol was moderate solvent for [HMIM]PF6 (close to poor solvent). The solubility parameter of [HMIM]PF6 was determined as 23.28 (J/cm3)0.5 by the extrapolation at 298.15 K.

Thermodynamic interactions and characterisation of naphthenic oil by inverse gas chromatography

The thermodynamic properties of naphthenic oil, a plasticiser, were investigated by means of inverse gas chromatography (IGC) using 10 different kinds of solvents as probes. Some thermodynamic parameters, such as specific retention volume, weight fraction activity coefficient, Flory–Huggins interaction parameter, partial molar heats of mixing and solubility parameter were obtained to judge the interactions between oil and solvents and the solubility of oil in these solvents. The results indicated that n-heptane, n-hexane, cyclohexane, chloroform, benzene and diethyl ether are good solvents for oil at experimental temperatures. The solubility parameters of oil varied from 13.94 to 13.21 (J cm−3)1/2 at temperature range 323–353 K. The solubility parameter of oil was calculated to be 14.38 (J cm−3)1/2 at room temperature, which is consistent with that obtained using surface tension–solubility parameter relation method.

Investigation of Thermodynamic Properties of SIS, SEBS, and Naphthenic Oil by Inverse Gas Chromatography

The thermodynamic properties of styrene-b-butene/ethylene-b-styrene, styrene-isoprene-styrene, and naphthenic oil, were investigated by means of inverse gas chromatography using 13 different kinds of solvents as the probes. Some thermodynamic parameters such as specific retention volume, weight fraction activity coefficient, Flory—Huggins interaction parameter, partial molar heats of mixing and solubility parameter, etc. were obtained to judge the interactions and the solubility between the polymer and solvents and the solubility of the polymers in these solvents. The results indicated that n-pentane, n-hexane, chloroform, tetrahydrofuran, and diethyl ether were good solvents for these polymers at experimental temperatures. The solubility parameter of styrene-b-butene/ethylene-b-styrene, styrene-isoprene-styrene, and naphthenic oil were calculated to be 16.99, 16.84, 14.39 (J/cm3)1/2 at 298.15 K by inverse gas chromatography, respectively, which were consistent with that obtained by intrinsic viscosity method, small group contribution method, or solubility parameter-surface tension method.

Inverse gas chromatographic characterization of triblock copolymer of polystyrene–poly(ethylene oxide)–polystyrene

AbstractThe thermodynamic properties of triblock copolymer of polystyrene–poly (ethylene oxide)–polystyrene (PS‐b‐PEO‐b‐PS) were investigated by means of inverse gas chromatography (IGC) using 15 different kinds of solvents as the probes. Some thermodynamic parameters, such as specific retention volume, molar heats of sorption, weight fraction activity coefficient, Flory‐Huggins interaction parameter, partial molar heats of mixing and solubility parameter were obtained to judge the interactions between PS‐b‐PEO‐b‐PS polymers and solvents and the solubility of the polymers in these solvents. It was found that increasing PEO content in PS‐b‐PEO‐b‐PS resulted in the increase in the solubility of PS‐b‐PEO‐b‐PS in alkanes and acetates solvents, but the solubility in alcohols had no change, and more PEO content in polymer caused a small decrease in the solubility parameter of PS‐b‐PEO‐b‐PS polymer, © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 2015–2022, 2007

A study of some equation‐of‐state parameters of poly(methylhydrosiloxane‐co‐dimethylsiloxane) with some solvents by gas chromatography

AbstractTrace amount of methyl acetate, ethyl acetate, tert‐butyl acetate, pentane, hexane, and heptane were passed through the chromatographic column loaded with poly(methylhydrosiloxane‐co‐dimethylsiloxane) coated on Chromosorb W. The retention diagrams of the solvents on the copolymer were plotted by means of specific retention volumes at temperatures between 40 and 80°C by inverse gas chromatography technique. In this study, some thermodynamic interaction parameters such as Flory–Huggins polymer–solvent interaction parameter, equation‐of‐state polymer–solvent interaction parameter, effective exchange energy parameter, and weight fraction activity coefficients at infinite dilution of the solvent were determined. Then, the exchange enthalpy parameter and entropy parameter were determined by using a relation for the enthalpy interaction parameter of the equation‐of‐state theory, which is arranged for the inverse gas chromatography conditions. Later, the partial molar heat of sorption and the partial molar heat of mixing were obtained. The solubility parameter of this copolymer was determined as 6.64 (cal/cm3)1/2 at room temperature. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 1627–1631, 2007

Investigation of thermodynamic properties of poly(methyl methacrylate-co- n-butylacrylate-co-cyclopentyl styryl-polyhedral oligomeric silsesquioxane) by inverse gas chromatography

The thermodynamic properties of poly(methyl methacrylate-co-butyl acrylate-co-cyclo -pentylstyryl polyhedral oligomeric silsesquioxane) (poly(MMA-co-BA-co-styryl-POSS)) were investigated by means of inverse gas chromatography (IGC) using 20 different kinds of solvents as the probes. Some thermodynamic parameters, such as molar heats of sorption, weight fraction activity coefficient, Flory–Huggins interaction parameter, partial molar heats of mixing and solubility parameter were obtained to judge the interactions between POSS-contained polymers and solvents and the solubility of the polymers in these solvents. It was found that acetates, aromatic hydrocarbons and hydrocarbon halides were good solvents, n–hexane, ethanol, n-propanol, n-butanol and n-pentanol were moderate solvents, while n-heptane, n-octane, n-nonane, n-decane and methanol were poor solvents for all POSS-contained polymers within the experimental temperature range. Incorporation of POSS in polymer increased the solubility of polymers in solvents, and the more the POSS in polymer was, the better the solubility was and stronger the hydrogen bonding interaction was, but the POSS content in polymers seemed to have no obvious influence on the solubility parameter of polymers.

Synthesis, characterization, and thermodynamic properties of poly(3‐mesityl‐2‐hydroxypropyl methacrylate)

AbstractPoly(3‐mesityl‐2‐hydroxypropyl methacrylate) (PMHPMA) was synthesized in a 1,4‐dioxane solution with 2,2′‐azobisisobutyronitrile as the initiator at 60°C. The homopolymer and its monomer were characterized with 1H‐ and 13C‐NMR, Fourier transform infrared, differential scanning calorimetry, thermogravimetric analysis, size exclusion chromatography, and elemental analysis techniques. According to size exclusion chromatography analysis, the number‐average molecular weight, weight‐average molecular weight, and polydispersity index of PMHPMA were 65,864 g/mol, 215,375 g/mol, and 3.275, respectively. According to thermogravimetric analysis, the carbonaceous residue value of PMHPMA was 14% at 500°C. The values of the specific retention volume, adsorption enthalpy, sorption enthalpy, sorption free energy, sorption entropy, partial molar free energy, partial molar heat of mixing, weight fraction activity coefficient of solute probes at infinite dilution (Ω), and Flory–Huggins interaction parameter (χ) were calculated for the interactions of PMHPMA with selected alcohols and alkanes by the inverse gas chromatography method at various temperatures. According to Ω and χ, selected alcohols and alkanes were nonsolvents for PMHPMA at 423–453 K. Also, the solubility parameter of PMHPMA (δ2) was found to be 24.24 and 26.33 (J/cm3)0.5 from the slope and intercept of (δ/RT) − χ/V1 = (2δ2/RT)δ1 − δ/RT at 443 K, respectively [where δ1 is the solubility parameter of the probe, V1 is the molar volume of the solute, T is the column temperature (K), and R is the universal gas constant]. The glass‐transition temperature of PMHPMA was found to be 386 and 385 K by inverse gas chromatography and differential scanning calorimetry techniques, respectively. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 101–109, 2006

Determination of Some Thermodynamic Parameters of Poly(Styrene‐Graft‐Ethyl Methacrylate) Using Inverse Gas Chromatography

In this study, the specific retention volumes, Vg o, were determined for poly(styrene‐g‐ethly methacrylate) obtained from grafting of poly(styrene‐co‐p‐chloromethyl styrene) having a 54% (by mole) chlorine content with ethyl methacrylate and a series of nonsolvent as probe, five n‐alkans, five alcohols and carbon tetrachloride, with the aid of inverse gas chromatography, in a temperature range of 333 to 463 K. Some thermodynamic properties, such as the sorption enthalpy, ΔHs, sorption free energy, ΔGs, sorption entropy, ΔSs, in the 373–403 K temperature range, the partial molar free energy, ΔG∞, and the partial molar heat of mixing, ΔH∞, in the temperature 413‐463 K range, were calculated from the relationships between the specific retention volumes and related properties. The weight fraction activity coefficients of probes as logarithmic value, ln Ω1 ∞, and Flory‐Huggins interaction parameters, χ12 ∞, between the polymer and probes, were estimated. Also, the glass transition temperature,Tg, and the solubility parameter, δ2, of the graft copolymer, were found to be about 85°C, and between 5.0–6.8 (cal/cm3)1/2 in the 413–463 temperature range K, respectively, and some extrapolations to room temperature were done and the results were discussed.

Physicochemical characterization of poly( tert-butyl acrylate- b-methyl methacrylate) prepared with atom transfer radical polymerization by inverse gas chromatography

Poly( tert-butyl acrylate) (P tBuA) was synthesized by atom transfer radical polymerization (ATRP) using methyl-2-bromo propionate (MBP) as an initiator in bulk at 80 °C. The successive ATRP of methyl methacrylate in diphenyl ether at 80 °C using previously obtained P tBuA as a macroinitiator led to formation of poly( tert-butyl acrylate- b-methyl methacrylate) (poly( tBuA- b-MMA)). The synthesized macroinitiator and block copolymer have controlled molecular weight and low polydispersity ( M w/ M n<1.2). The block copolymer was characterized by gel permeation chromatography (GPC) and 1H NMR. The retention diagrams of poly( tBuA- b-MMA) for some aliphatic esters and aromatic hydrocarbons were obtained using inverse gas chromatography (IGC) technique. The glass transition temperatures, T gs of poly( tBuA- b-MMA) were determined by both differential scanning calorimeter (DSC) and IGC. It was observed that the block copolymer represents three T gs at 50, 75 and 100 °C by IGC although it represents only one T g at 71 °C by DSC. After the column was quenched from 180 to 0 °C, the T g at 100 °C shifted to 105 °C however others did not change. Specific retention volumes, V g 0 and the thermodynamical polymer–solvent interaction parameters such as Flory–Huggins, χ 12 ∞ , equation-of-state, χ 12 * and effective exchange energy, X eff were found for all studied solvents. Partial molar heat of sorption, Δ H ¯ 1 , sorp , partial molar heat of mixing, Δ H ¯ 1 ∞ and molar heat of vaporization, Δ H v, were determined. In addition, the solubility parameter of the corresponding block copolymer, δ 2 was determined as 11.0 (cal/cm 3) 1/2 at 25 °C.

Synthesis, characterization and thermodynamic properties of poly(3-mesityl-2-hydroxypropyl methacrylate- co- N-vinyl-2-pyrrolidone)

Poly(3-mesityl-2-hydroxypropyl methacrylate- co- N-vinyl-2-pyrrolidone) P(MHPMA- co-VP) was synthesized in 1, 4-dioxane solution using benzoyl peroxide (BPO) as initiator at 60 °C. The copolymer was characterized by 1H 13C NMR, FT-IR, DSC, TGA, size exclusion chromatography analysis (SEC) and elemental analysis techniques. According to SEC, the number-average molecular weight ( M n), weight-average molecular weight ( M w) and polydispersity index (PDI) values of PMHPMA- co-VP were found to be 58,000, 481,000 g/mol and 8.26, respectively. According to TGA, carbonaceous residue value of PMHPMA- co-VP was found to be 6% at 500 °C. Also, some thermodynamic properties of PMHPMA- co-VP such as the adsorption enthalpy, Δ H a, molar evaporation enthalpy, Δ H v, the sorption enthalpy, Δ H 1 s , sorption free energy, Δ G 1 s , sorption entropy, Δ S 1 s , the partial molar free energy, Δ G 1 ∞ , the partial molar heat of mixing, Δ H 1 ∞ , at infinite dilution was determined for the interactions of PMHPMA- co-VP with selected alcohols and alkanes by inverse gas chromatography (IGC) method in the temperature range of 323–463 K. According to the specific retention volumes, V g 0 , the weight fraction activity coefficients of solute probes at infinite dilution, Ω 1 ∞ , and Flory–Huggins interaction parameters, χ 12 ∞ between PMHPMA- co-VP-solvents were determined in 413–453 K. According to Ω 1 ∞ and χ 12 ∞ , selected alcohols and alkanes were found to be non-solvent for PMHPMA- co-VP at 413–453 K. The glass transition temperature, T g, of the PMHPMA- co-VP found to be 370 and 363 K, respectively, by IGC and DSC techniques, respectively.

Determination of thermodynamic properties of macroporous glycidyl methacrylate‐based copolymers by inverse gas chromatography

AbstractMacroporous crosslinked poly(glycidyl methacrylate‐co‐ethylene glycol dimethacrylate) (PGME) was synthesized by suspension copolymerization and modified by ring‐opening reaction of the pendant epoxy groups with ethylene diamine (EDA). Inverse gas chromatography (IGC) at infinite dilution was applied to determine the thermodynamic interactions of PGME and modified copolymer, PGME‐en. The specific surface areas of the initial and modified copolymer samples were determined by the BET method, from low‐temperature nitrogen adsorption isotherms. The specific retention volumes, V, of 10 organic compounds of different chemical nature and polarity (nonpolar, donor, or acceptor) were determined in the temperature range 333–413 K. The weight fraction activity coefficients of test sorbates, $\Omega_1^\infty$, and Flory–Huggins interaction parameters, $\chi_{12}^\infty$, were calculated and discussed in terms of interactions of sorbates with PGME and PGME‐en. Also, the partial molar free energy, $\Delta G_1^S$, partial molar heat of mixing, $\Delta H_1^\infty$, sorption molar free energy, ΔG, sorption enthalpy ΔH, and sorption entropy, ΔS, were calculated. Glass transitions in PGME and PGME‐en, determined from IGC data, were observed in the temperature range 373–393 K and 363–373 K, respectively. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 2524–2533, 2005

Determination of secondary transitions and thermodynamic interaction parameters of poly (ether imide) by inverse gas chromatography

The retention diagrams of poly(ether imide) for ethyl benzene, n-propyl benzene, isopropyl benzene, chloro benzene, n-butyl acetate, tert-butyl acetate, isoamyl acetate, n-nonane, n-decane, n-undecane, n-dodecane and n-tridecane were obtained by inverse gas chromatography technique. In this work, the slope changes on the diagram were assigned as secondary transitions. The secondary transition temperatures obtained by inverse gas chromatography technique are in good agreement with the ones obtained by thermally stimulated depolarization current in the literature. Specific retention volume, V g 0, the weight fraction activity coefficients of the solvents at infinite solution, Ω1∞, Flory-Huggins polymer-solvent interaction parameters,χ12∞, equation-of-state polymer-solvent interaction parameters,χ12*, effective exchange energy parameters, X eff were determined. Later, the partial molar heat of sorption, $\Delta\bar{H}_{1,sorp}$ and the partial molar heat of mixing, $\Delta\bar{H}_1^{\infty}$ were obtained. The solubility parameter of poly(ether imide), δ2 was determined as 10.7 (cal/cm3)1/2 by extrapolation of the δ2 values obtained by considering the free volume effects from studied temperature range to room temperature.

Investigation of Thermodynamic Properties of PIBMA-PVC (50%/50%) and P-4-t-BS-PVC (50%/50%) Blends Systems by Inverse Gas Chromatography

ABSTRACT The specific retention volumes, , values of the poly (isobutyl methacrylate)-poly (vinyl chloride) (PIBMA-PVC) (50%/50%) and poly (-4-tert-butyl styrene)-poly (vinyl chloride) (P-4-t-BS-PVC) (50%/50%) blends-probe systems were calculated between 383 and 423 K by inverse gas chromatography technique. According to these data, the thermodynamic properties such as the sorption enthalpy (), sorption free energy (), sorption entropy (), the partial molar free energy (), and the partial molar heat of mixing, () at infinite dilution were determined for the interactions of (PIBMA-PVC) (50%/50%) and (P-4-t-BS-PVC) (50%/50%) blends with alcohols and aromatics and CHCl3 by inverse gas chromatography method in the temperature range of 383–423 K. The sorption values and values were observed to be exothermic, and , , and values were observed to be endothermic. The values of PIBMA-PVC (50%/50%) and P (-4-t-BS)-PVC (50%/50%) blends-alcohols systems changed from 9.73 to 18.17 kJ/mol and from 10.00 to 16.83 kJ/mol, respectively. Flory-Huggins interaction parameters, χ12, χ13, χ14, χ1(23) and χ1(24) values of PVC, PIBMA, P (4-t-BS), PIBMA-PVC (50%/50%) and P (-4-t-BS)-PVC (50%/50%) blend systems were determined at 413–423 K. In addition, χ23′ and χ24′ values of alcohols changed from 1.191 to 2.473 and from 1.342 to 1.839 for PIBMA-PVC (50%/50%) and P (-4-t-BS)-PVC (50%/50%) blends, respectively, at 413 K.