Assessment of the thermodynamic properties of poly(2,2,2-trifluoroethyl methacrylate) by inverse gas chromatography

Exploring the Application of Advanced Chromatographic Methods to Characterize the Surface Physicochemical Properties and Transition Phenomena of Polystyrene-b-poly(4-vinylpyridine)

The linear diblock copolymer polystyrene-b-poly(4-vinylpyridine) (PS-P4VP) is an important copolymer recently used in many applications such as optoelectronics, sensors, catalysis, membranes, energy conversion, energy storage devices, photolithography, and biomedical applications. (1) Background: The surface thermodynamic properties of PS-P4VP copolymers are of great importance in many chemical and industrial processes. (2) Methods: The inverse gas chromatography (IGC) at infinite dilution was used for the experimental determination of the retention volumes of organic solvents adsorbed on copolymer surfaces as a function of temperature. This led to the variations in the free energy of interaction necessary to the evaluation of the London dispersive and polar acid-base surface energies, the polar enthalpy and entropy, the Lewis acid-base constants, and the transition temperatures of the PS-P4VP copolymer. (3) Results: The application of the thermal Hamieh model led to an accurate determination of the London dispersive surface energy of the copolymer that showed non-linear variations versus the temperature, highlighting the presence of two transition temperatures. It was observed that the Lewis acid-base parameters of the copolymer strongly depend on the temperature, and the Lewis base constant of the solid surface was shown to be higher than its acid constant. (4) Conclusions: An important effect of the temperature on the surface thermodynamic properties of PS-P4VP was proven and new surface correlations were determined.

Thermal Surface Properties, London Dispersive and Polar Surface Energy of Graphene and Carbon Materials Using Inverse Gas Chromatography at Infinite Dilution

The thermal surface properties of graphenes and carbon materials are of crucial importance in the chemistry of materials, chemical engineering, and many industrial processes.

BACKGROUND

The determination of these surface properties is carried out using inverse gas chromatography at infinite dilution, which leads to the retention volume of organic solvents adsorbed on solid surfaces. This experimental and fundamental parameter actually reflects the surface thermodynamic interactions between injected probes and solid substrates.

METHODS

The London dispersion equation and the Hamieh thermal model are used to quantify the London dispersive and polar surface energy of graphenes and carbon fibers as well their Lewis acid-base constants by introducing the coupling amphoteric constant of materials.

RESULTS

The London dispersive and polar acid-base surface energies, the free energy of adsorption, the polar enthalpy and entropy, and the Lewis acid-base constants of graphenes and carbon materials are determined.

CONCLUSIONS

It is shown that graphene exhibited the highest values of London dispersive surface energy, polar surface energy, and Lewis acid-base constants. The highest characteristics of graphene justify its great potentiality and uses in many industrial applications.

Temperature Dependence of the Polar and Lewis Acid-Base Properties of Poly Methyl Methacrylate Adsorbed on Silica via Inverse Gas Chromatography

The adsorption of polymers on solid surfaces is common in many industrial applications, such as coatings, paints, catalysis, colloids, and adhesion processes. The properties of absorbed polymers commonly vary with temperature. In this paper, inverse gas chromatography at infinite dilution was used to determine the physicochemical characterization of PMMA adsorbed on silica. A new method based on the London dispersion equation was applied with a new parameter associating the deformation polarizability with the harmonic mean of the ionization energies of the solvent. More accurate values of the dispersive and polar interaction energies of the various organic solvents adsorbed on PMMA in bulk phase and PMMA/silica at different recovery fractions were obtained, as well as the Lewis acid-base parameters and the transition temperatures of the different composites. It was found that the temperature and the recovery fraction have important effects on the various physicochemical and thermodynamic properties. The variations in all the interaction parameters showed the presence of three transition temperatures for the different PMMA composites adsorbed on silica with various coverage rates, with a shift in these temperatures for a recovery fraction of 31%. An important variation in the polar enthalpy and entropy of adsorption, the Lewis acid-base parameters and the intermolecular separation distance was highlighted as a function of the temperature and the recovery fraction of PMMA on silica.

INVERSE GAS CHROMATOGRAPHY STUDY OF HANSEN SOLUBILITY PARAMETERS OF RUBBER PROCESS OILS (DAE, TDAE, MES, AND NAP)

Process oils are used for rubbers to improve their flexibility and processability in industry. The solubility parameter is a convenient way to determine the solubility of materials. Inverse gas chromatography was used to calculate the solubility parameters and depict solubility spheres for distillated aromatic extract (DAE), treated distillate aromatic extract (TDAE), mildly extracted solvate (MES), and hydro processed naphthenic oil (NAP). Results showed that despite the similarity in values of the solubility parameters of DAE and TDAE at ambient temperature, increasing temperature led to a significant difference in values. In contrast to other oils, TDAE showed a better compatibility with polar solvents. In addition, the interaction parameters showed no specific dependence on the temperature for DAE, MES, and NAP, except for polar solvents and TDAE. DAE had the highest compatibility with aromatic solvents. Upon raising the temperature to values greater than 100 °C, the compatibility trend between oils and toluene was the same for all oils investigated, except for TDAE, which increased with increasing temperature whereas others showed a reduction. The increase in the alkyl chain was also effective in increasing the compatibility of the probes as well as their interaction parameter values. The solubility parameters (δ2) of process oils were determined to be 18.9, 18.9, 18.5, and 19.0 (J/cm3)0.5 for DAE, TDAE, NAP, and MES at 25 °C, respectively.

Assessment of the Thermodynamic Properties of DL-p-Mentha-1,8-diene, 4-Isopropyl-1-Methylcyclohexene (DL-limonene) by Inverse Gas Chromatography (IGC)

Limonene is a colorless liquid hydrocarbon and had been investigated as a plasticizer for many plastics. Prediction of solubility between different materials is an advantage in many ways, one of the most convenient ways to know the compatibility of materials is to determine the degree of solubility of them in each other. The concept of "solubility parameter" can help practitioners in this way.In this study, inverse gas chromatography (IGC) method at infinite dilution was used for determination of the thermodynamic properties of DL-p-mentha-1,8-diene, 4-Isopropyl-1-methylcyclohexene (DL-limonene). The interaction between DL-limonene and 13 solvents were examined in the temperature range of 63-123°C through the assessment of the thermodynamic sorption parameters, the parameters of mixing at infinite dilution, the weight fraction activity coefficient and the Flory-Huggins interaction parameters. Additionally, the solubility parameter for DL-limonene and the temperature dependence of these parameters was investigated as well.Results show that there is a temperature dependence in solubility parameter, which increases by decreasing temperature. However, there were no specific dependence between interaction parameters and temperature, but chemical structure appeared to have a significant effect on them as well as on the type and strength of intermolecular interactions between DL-limonene and investigated solvents. The solubility parameter δ2 of DL-limonene determined to be 19.20 (J/cm3)0.5 at 25°C.

Quantitative Analysis of Relationship between Hansen Solubility Parameters and Properties of Alkali Lignin/Acrylonitrile-Butadiene-Styrene Blends

Blends of alkali lignin and acrylonitrile-butadiene-styrene (ABS) resin are physically mixed and injected into the injection molding system. Although the components of the blend are bound together by intermolecular forces, noticeable phase separation still occurs. In the present study, inverse gas chromatography technology was used to characterize the Hansen solubility parameters of alkali lignin/ABS blends. The relationship between the Hansen solubility parameters and thermodynamic properties was then determined. Hansen solubility parameters, at room temperature, of alkali lignin/ABS blends containing 0, 10, 20, and 30 wt % alkali lignin were 17.40, 19.20, 18.98, and 17.37 (J/cm³)^0.5, respectively. Hansen solubility parameters of the blends were shown, both experimentally and theoretically, to be related to their mechanical and thermal properties.

Correlation between Solubility Parameters and Properties of Alkali Lignin/PVA Composites

Although lignin blending with thermoplastic polymers has been widely studied, the usefulness of the lignin⁻polymer composites is limited by the poor compatibility of the two components. In the present study, alkali lignin/PVA composite membranes were prepared by incorporating 10%, 15%, 20% and 25% alkali lignin into the composites. The thermodynamic parameters of the composites were measured using inverse gas chromatography (IGC). Composite membranes with 10%, 15%, 20%, and 25% alkali lignin had solubility parameters of 17.51, 18.70, 16.64 and 16.38 (J/cm³)0.5, respectively, indicating that the solubility parameter firstly increased, and then decreased, with increasing proportions of alkali lignin. When the alkali lignin content was 15%, the composites had the largest solubility parameters. The composite membrane with an alkali lignin content of 15% had a tensile strength of 18.86 MPa and a hydrophilic contact angle of 89°. We have shown that the solubility parameters of blends were related to mechanical and hydrophilic properties of the composites and the relationships have been verified experimentally and theoretically.

Inverse gas chromatography applications: a review

Inverse gas chromatography (IGC) is a versatile, powerful, sensitive and relatively fast technique for characterizing the physicochemical properties of materials. Due to its applicability in determining surface properties of solids in any form such as films, fibres and powders of both crystalline and amorphous structures, IGC became a popular technique for surface characterization, used extensively soon after its development. One of the most appealing features of IGC that led to its popularity among analytical scientists in early years was its similarity in principle to analytical gas chromatography (GC). The main aspect which distinguishes IGC experiments from conventional GC is the role of mobile and stationary phases. Contrary to conventional GC, the material under investigation is placed in the chromatographic column and a known probe vapour is used to provide information on the surface. In this review, information concerning the history, instrumentation and applications is discussed. Examples of the many experiments developed for IGC method are selected and described. Materials that have been analysed include polymers, pharmaceuticals, minerals, surfactants, and nanomaterials. The properties that can be determined using the IGC technique include enthalpy and entropy of sorption, surface energy (dispersive and specific components), work of co/adhesion, miscibility and solubility parameters, surface heterogeneity, glass transition temperature, and specific surface area.