Search

For the synthesis of ionogels containing microcrystalline cellulose (MCC) and Na-bentonite (Na-Bent), ionic liquid (IL) 1-butyl-3-methylimidazolium acetate was used as an MCC solvent. Characterization and research of the physicochemical properties of the synthesized materials were carried out using methods such as SEM, WAXS, thermal analysis, FTIR, conductometry, and viscometry. WAXS analysis showed an increase in the interlayer distance of Na-bentonite in composites due to the intercalation of IL molecules. Based on the data on the characteristic temperatures of thermal degradation, enhanced thermal stability of triple IL/Na-Bent/MCC ionogels was revealed compared to that for cellulose-free systems. It was found that the electrical conductivity of both triple IL/Na-Bent/MCC and binary IL/MCC ionogels was non-monotonous. The data obtained can be used in the formation of multifunctional coatings with enhanced thermal stability. [ABSTRACT FROM AUTHOR]

• Two-component ionogels containing clay minerals and ionic liquids were prepared. • The thermal behavior of the synthesized ionogels and pristine ILs was investigated using DSC and TG techniques. • A confinement effect was revealed in the studied materials. • The glass-transition temperature shifted towards higher temperatures with the introduction of aluminosilicate. • The characteristic temperatures of thermal decomposition of ionogels were lower than those for the pristine ILs. Two-component ionogels containing clay minerals such as montmorillonite K 10 (Mnt- K 10), bentonite (Bent), and halloysite (Hly), as well as imidazolium-based ionic liquids (ILs) were prepared in present work. The ILs that were used in the synthesis included a bis(trifluoromethylsulfonyl) imide anion (TFSI-) and various cations: 1-ethyl-3-methylimidazolium (EMIm+), 1-propyl-3-methylimidazolium (PMIm+), 1-butyl-3-methylimidazolium (BMIm+), and 1-butyl-2,3-dimethylimidazolium (BDMIm+). The thermal behavior of the synthesized ionogels and neat ILs was investigated using differential scanning spectroscopy (DSC) and thermogravimetric analysis (TG). It was found that the thermograms of PMImTFSI, BMImTFSI, and BDMImTFSI showed inflections corresponding to glass-transition, which shifted towards higher temperatures with the introduction of aluminosilicate. The largest shifts compared to the neat ILs were observed for IL/Bent ionogels. It was assumed that the identified differences in the thermal behavior between the neat and clay-entrapped ILs (confinement effect) are associated with an increased role of ion-wall interactions compared to ion-ion interactions. When studying the thermal stability of the materials under consideration, two opposite trends were noted. On the one hand, the characteristic temperatures of thermal decomposition of the synthesized ionogels were lower than those for the neat ILs. But on the other hand, when introducing aluminosilicate into any IL, a decrease in the maximum rate of thermal decomposition was observed in accordance with series of IL > IL/Mnt- K 10 > IL/Hly > IL/Bent. [ABSTRACT FROM AUTHOR]

In this study, an ionic liquid (IL), 1-butyl-3-methylimidazolium acetate, was used to prepare ionogels with microcrystalline cellulose (MCC) and halloysite (Hal). SEM, XRD, TG, DSC, FTIR spectroscopy, conductometry and mechanical tests were used to study the morphology, structure, thermal behaviour and electrophysical and mechanical characteristics of synthesised ionogels. XRD analysis showed a slight decrease in the interlayer space of halloysite in ionogels containing MCC, which may have been associated with the removal of residual water molecules resulting from hydrophilic IL anions and polymer macromolecules. A change in conductivity and glass-transition temperature of the ionic liquid was revealed due to intercalation into halloysite (a confinement effect) and modification with cellulose. For triple IL/Hal/MCC ionogels, the characteristic thermal degradation temperatures were higher than the corresponding values for IL/Hal composites. This indicates that the synthesised IL/Hal/MCC ionogels are characterised by a greater thermal stability than those of IL/Hal systems. [ABSTRACT FROM AUTHOR]

Composites of montmorillonite K10 (MMT K10) and ionic liquid (IL) containing a 1-butyl-3-methyl-imidazolium cation ([BMIm]+) and various anions, such as bis (trifluoromethylsulfonyl) imide ([NTf2]−), trifluoromethanesulfonate ([OTf]−), and dicyanamide ([DCA]−) have been obtained in this work. A number of methods, such as dynamic light scattering (DLS), scanning electron microscopy (SEM), X-ray diffraction (XRD), thermal gravimetry (TG), differential scanning calorimetry (DSC), Fourier-transform infrared (FTIR) spectroscopy, and nitrogen adsorption–desorption have been used to characterize clay, and to study the structure and thermal behaviour of the composites. It has been found that the MMT K10 powder has a narrow particle size distribution with a peak at 246 nm and a mesoporous structure (SBET=195 m2/g). According to the FTIR spectra, MMT K10/IL interaction depends on the IL type. It has been identified that confined ionic liquid interacts with both clay and adsorbed water in accordance with the hydrophilicity and size of the anion, in the following order: [DCA]− > [OTf]− > [NTf2]−. Characteristic temperatures of glass transition, crystallization, and melting have been determined for the ionic liquids under study and their MMT K10 composites. It has been revealed that when IL is adsorbed on the surface of clay, the phase transitions in IL change. The greatest changes are observed in the case of BMImNTf2. By applying the method of thermogravimetric analysis, it is shown that composite formation is accompanied by a decrease in the IL thermal stability. Apparently, the highly developed surface of montmorillonite K10, obtained by acid treatment, plays a major role in the decrease in the IL's thermal stability. The influence of the IL anion on the thermal and spectral characteristics of an MMT K10/IL composite was studied for the first time. [ABSTRACT FROM AUTHOR]