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The present study investigates, thermal properties of polyethylene glycol (PEG) and various polymorphs of calcium carbonate (CaCO3) as blends. The prepared calcite, aragonite, and vaterite forms of CaCO3 were confirmed by x‐ray diffraction (XRD). Differential scanning calorimeter (DSC) revealed that, PEG‐calcite blend (composition 40/60 wt%), exhibited maximum enthalpy (112.9 ± 0.87 J/g). Aragonite and vaterite blends of similar composition displayed lower enthalpies (73.7 ± 0.61 J/g and 61.3 ± 0.75 J/g), which can be attributed to irregularities in crystal lattice and secondary interactions. Thermal gravimetric analysis (TGA) of PEG‐calcite revealed its impressive thermal stability, as blend was stable up to 423°C, higher than decomposition temperature of PEG. DSC analysis of PEG‐calcite after 50 cycles showcased excellent thermal reliability of blend, with enthalpy decreasing to only 108.5 ± 0.52 J/g. Stability of material was further supported by Fourier transform infrared spectroscopy (FTIR), where position and shape of peaks were found to be intact, suggesting no new compound formation. Field emission scanning electron microscopy (FESEM) suggested strong adhesion and wrapping of PEG around calcite particles, facilitated by cross‐hydrogen bonding between carbonate group and PEG. PEG‐calcite blend exhibited high thermal conductivity (0.74 ± 0.05 W/mK), highlighting potential applications in thermal management systems. [ABSTRACT FROM AUTHOR]

This investigation includes the synthesis and characterization of a new series of ionic liquids (ILs) based on the tetraalkylammonium dication for the absorption of CO2, a step towards the development of more efficient and sustainable technologies. It was possible to synthesize amine-substituted PEG diacrylate by modifying poly(ethylene glycol) (PEG), which was then quaternized with 1-bromopentane to produce the IL PDBr. The other IL products, PDNTf2, PDBF4 and PDPF6, were synthesized via the metathesis of PDBr with the appropriate salt. The synthesized products were characterized using various techniques, such as FTIR, 1H and 13C NMR, elemental analysis, and density and viscosity meters, and evaluated as potential sorbents for CO2 capture. DSC and TGA were used to examine the thermal properties of the ILs. As observed from their thermal degradation behavior, the ILs exhibited two-stage disintegration with thermal stability up to 150 °C. The pressure drop method was used to study the sorption capacity of the ILs towards CO2. The sorption investigation showed that when the pressure is increased, the CO2 absorption increases. Equilibrium is reached in 40 minutes, demonstrating a rapid absorption rate. The IL with the [BF4]− anion (PDBF4) demonstrated a maximum sorption capacity of 0.577 mole fraction of CO2, and can be regenerated and reused efficiently with less than 0.5% variation from its original absorption capacity. The CO2 absorption capacity for the ILs with other anions follows the trend: Br ≈ NTf2 < PF6 < BF4. This work shows that tetraalkylammonium-based dicationic ILs are adaptable, making them a suitable material for many applications, including sustainable CO2 capture technology. [ABSTRACT FROM AUTHOR]

Poly(ethylene glycol) (PEG) is known to be very effective phase change material (PCM), which has been processed by various techniques. Efforts for development of better processing technique are always on, to make the process product and performance superior. Microwave technology based process development for the preparation of form stable phase change composites was attempted, with the motivation of establishing a green technique, which will be energy and time efficient and require minimum amount of solvent. The process could easily be scaled for large scale production of PCM blends. The microwave-assisted blending of PEG and cellulose acetate (CA) was carried out in various ratios resulting in the formation of biodegradable form-stable PCM. PEG acted as the latent heat storage material and cellulose acetate as the supporting material. As a result of microwave treatment, a high loading capacity of 96.5 wt% PEG was achieved without any leakage during the transition process. The blending was confirmed by Fourier-transform infrared spectroscopy (FTIR) analysis which showed no chemical bonds between PEG and CA. Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) indicated that maximum enthalpy of 155 J/g was attained and the material was found to have good thermal stability. The surface properties of these materials were studied by using contact angle for various weight percentages of PEG. The X-ray diffraction (XRD) investigation revealed that the crystallinity of the PEG-CA blend increased with increasing concentration of PEG. The morphology was studied with field-emission scanning electron microscopy (FESEM) and atomic force microscopy (AFM) suggesting a homogeneous network formation of the blend. [ABSTRACT FROM AUTHOR]