Application of inverse gas chromatography in physicochemical characterization of phenolic resin adhesives

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.

Characteristics of Multifunctional, Eco-Friendly Lignin-Al₂O₃ Hybrid Fillers and Their Influence on the Properties of Composites for Abrasive Tools

The main aim of the present study was the preparation and comprehensive characterization of innovative additives to abrasive materials based on functional, pro-ecological lignin-alumina hybrid fillers. The behavior of lignin, alumina and lignin-Al₂O₃ hybrids in a resin matrix was explained on the basis of their surface and application properties determined by inverse gas chromatography, the degree of adhesion/cohesion between components, thermomechanical and rheological properties. On the basis of the presented results, a hypothetical mechanism of interactions between lignin and Al₂O₃ as well as between lignin-Al₂O₃ hybrids and phenolic resins was proposed. It was concluded that lignin compounds can provide new, promising properties for a phenolic binder combining the good properties of this biopolymer as a plasticizer and of alumina as a filler improving mechanical and thermal properties. The use of such materials may be relatively non-complicated and efficient way to improve the performance of bonded abrasive tools.

Physicochemical Characterization of Functional Lignin-Silica Hybrid Fillers for Potential Application in Abrasive Tools

Functional lignin–SiO₂ hybrid fillers were prepared for potential application in binders for phenolic resins, and their chemical structure was characterized. The properties of these fillers and of composites obtained from them with phenolic resin were compared with those of systems with lignin or silica alone. The chemical structure of the materials was investigated by Fourier transform infrared spectroscopy (FT-IR) and carbon-13 nuclear magnetic resonance spectroscopy (¹³C CP MAS NMR). The thermal stability of the new functional fillers was examined by thermogravimetric analysis–mass spectrometry (TG-MS). Thermo-mechanical properties of the lignin–silica hybrids and resin systems were investigated by dynamic mechanical thermal analysis (DMTA). The DMTA results showed that abrasive composites with lignin–SiO₂ fillers have better thermo-mechanical properties than systems with silica alone. Thus, fillers based on lignin might provide new, promising properties for the abrasive industry, combining the good properties of lignin as a plasticizer and of silica as a filler improving mechanical properties.