查看更多>>摘要：? 2021 The Korean Society of Industrial and Engineering ChemistryIn this work, a novel synthesis of homogeneous molybdenum silicate spheres under non-aqueous conditions is presented. A preparation method is based on the condensation of molybdenum metal–organic framework-based precursor solution prepared via a microwave-assisted approach from bis(acetylacetonato)dioxomolybdenum and biphenyl-4,4′-dicarboxylic acid with 3-aminopropyltriethoxysilane under non-aqueous conditions. The as-prepared product was calcined at 500 °C to obtain amorphous and porous molybdenum silicate microspheres with homogeneously distributed molybdenum species within silicate matrix. The microspheres exhibit an average size of about 480 nm. This material was further studied as a heterogeneous catalyst for the epoxidation of olefins via the model catalytic epoxidation of cyclohexene with cumylhydroperoxide. High catalytic activity at the moderate temperature (65 °C) with the conversion of 86% after 2 h and the high selectivity to cyclohexene oxide has been achieved. In addition, molybdenum silicate microspheres exhibit catalytic activity and high selectivity in the oxidation of aniline to nitrosobenzene.
查看更多>>摘要：? 2021 The Korean Society of Industrial and Engineering ChemistryTo exploit the advanced corrosion inhibitor for mild steel in acidic solution, N, N, N, N, N′-pentakis (2-hydroxyethyl)-1,4,7-triazaheptane (PHET) was synthesized by a facile process, which was confirmed by FT-IR, NMR and EI-MS. Inhibition effect of PHET was examined on mild steel in 1.0 M HCl solution by using weight loss, electrochemical tests and surface analyses. The results showed that the optimal concentration of PHET in HCl solution was 400 mg/L corresponding to the inhibitive efficiency of 93% at 293 K. PHET presented superior and durable corrosion inhibition performance for mild steel. Meanwhile, PHET acted as a mixed-type inhibitor which affects both anodic and cathodic reactions of the corrosion process. PHET could be absorbed on mild steel through forming complexes with ferrous ions that acted as protective film, which was supported by UV–vis and XPS analyses. The adsorption process of PHET molecules on mild steel, following Langmuir adsorption isotherm, was an exothermal process and belonged to mixed adsorption mechanisms (ΔGads°=-31.78 kJ mol?1, 293 K) between physisorption and chemisorption. Besides, theoretical calculations were conducted to give further investigation on the inhibition mechanism of PHET and elucidated the adsorption behaviour of PHET. PHET synthesized in this work also can be extended to use for the corrosion protection of other metals in acidic medium.
查看更多>>摘要：? 2021 The Korean Society of Industrial and Engineering ChemistryIn preparing a non-polar polymer composite employing functional fillers, the chemical inertness of non-polar polymer does not easily allow efficient interfacial affinity change. Here, a wet-free interfacial affinity modulation to incompatible polypropylene (PP)/graphite nanoplatelet (GNP) composite was performed with a nitrogen plasma-assisted mechanochemical (PM) treatment. It was surprising that the PP/GNP composite subjected to the PM treatment demonstrated the formation of chemical bonds between PP and GNP and the dramatic improvement of GNP dispersion in PP, resulting in a novel PP composite deploying efficient heat transfer along with mechanical performance comparable to that of neat PP. Due to the interfacial affinity control, the elongation at break of the PM-treated PP/GNP composite with 5 wt% of GNP was improved ten-folds compared to the untreated PP/GNP composite. The thermal conductivity of the PM-treated PP/GNP composite employing 20 wt% of GNP reached ca. 21 W/mK, whereas the untreated PP/GNP composite containing comparable amount of GNP exhibited 7 W/mK. Based on the findings, it can be noted that a solvent-free plasma-assisted mechanochemical treatment could be meaningful in developing a novel composite capable of efficient mechanical load transfer and heat transfer with non-polar polymers known to be poor at chemical reaction.
查看更多>>摘要：? 2021 The Korean Society of Industrial and Engineering ChemistryHighly ordered mesoporous molybdenum dioxide (meso-MoO2) was successfully synthesized by a nano-replication method using a mesoporous silica template with 3D cubic Ia3d mesostructure. Structural analyses using X-ray diffraction, N2 sorption, and electron microscopy indicated that the meso-MoO2 material exhibited high surface area (106 m2/g), large pore volume (0.66 cm3/g), and well-defined mesopores. Under the optimized reaction conditions, the meso-MoO2 catalyst showed excellent catalytic performances for the acetalization of glycerol with acetone (95.8% of glycerol conversion, and 97.8% of solketal selectivity) at 20 °C, due to its high surface area with large number of acid sites. During recycling, the meso-MoO2 catalyst exhibited a slight decrease in activity; and after a simple regeneration at 350 °C, the catalytic performances could be completely recovered. More importantly, a partial hydrophobic treatment of the meso-MoO2 catalyst dramatically enhanced the water-tolerance during the catalytic reaction.
查看更多>>摘要：? 2021 The Korean Society of Industrial and Engineering ChemistryThis study investigated the use of ionic liquids such as 1-butyl-3-methylimidazolium chloride, 4-butyl-4-methyl morpholinium chloride, 1-butyl-1-methylpiperidinium chloride, and 1,3-dimethylimidazolium methylphosphite to dissolve cellulose, hemicellulose, and lignin biomass, as alternatives to highly toxic organic solvents. The biomass treated with the ionic liquids is characterized by scanning electron microscopy, X-ray diffraction, thermogravimetric analysis, and Fourier-transform infrared spectroscopy. The X-ray diffraction results revealed that most of the biomass treated with ionic liquids had low crystallinity after treatment with the ionic liquids. Thermogravimetric analysis confirmed that the pyrolysis temperature of the biomass treated with the ionic liquid decreased. However, it was found that the pyrolysis temperature of the biomass was increased again after the ionic liquid was washed with an antisolvent. This result was interpreted using Fourier-transform infrared spectroscopy to show that the O–H hydrogen bonding of cellulose was restored. The experimental results from this study can help provide a better understanding of the biomass regeneration mechanism of ionic liquids and increase the applicability of biomass in various fields.
查看更多>>摘要：? 2021 The Korean Society of Industrial and Engineering ChemistryThe photothermal effect resulting from the local surface plasmon phenomenon of metal nanoparticles is essentially a light–heat conversion mechanism, wherein the heat is generated around the nanoparticles owing to the absorption of light by the nanoparticles. A pigment exhibiting the photothermal effect can be used as a multifunctional nano-pigment providing high heat energy from a small amount of light energy as well as a bright color. In this study, a grayish blue nano-pigment (GBNP) was synthesized using silica nanoparticles and hollow Au nanoparticles that exhibited a relatively high photothermal effect in the near-infra red (NIR) region. By irradiating light in the NIR region, GBNP could selectively produce stable thermal energy with a photothermal efficiency of 39%. It was mixed with paint to confirm its applicability to pigments and heat-generation performance. The surface of paint containing 4 wt% GBNP was increased to 110 °C, exhibiting a stable heat-generation performance under both repeated and continuous NIR irradiation. Furthermore, the thermal energy generated due to the photothermal effect implied the high evaporation efficiency of water droplets on the surface. This pigment might be utilized in applications where a selectively high temperature needs to be maintained continuously for bacterial-growth prevention and moisture control.
查看更多>>摘要：? 2021 The Korean Society of Industrial and Engineering ChemistryIn this study, high-efficiency sub-module quasi-solid-state (QS) dye-sensitized solar cells (DSSCs) are prepared using silicon dioxide (SiO2) nanofiller and polyethylene oxide (PEO)-based iodide composite electrolyte pastes. The influence of various amounts of nanofiller on the ionic conductivity, ion diffusion coefficient, and the performance of the devices are explored. The addition of SiO2 decreases the ion transport properties in the plain polymer electrolyte pastes. X-ray photoelectron spectroscopy analysis confirms the adsorption of polyiodide and lithium ions on the surface of the SiO2. This effect causes a reduction in the concentration of ions near the photoelectrode. As a result, the QS-DSSCs using 1 wt.% SiO2 nanofillers have higher recombination resistance and a longer electron lifetime than the other DSSCs. Therefore, high open-circuit voltage (0.794 V) and high efficiency (8.83%) are obtained for the corresponding QS-DSSCs. This efficiency is much better than the efficiencies of the devices employing the pristine polymer electrolyte paste and liquid electrolytes. This composite electrolyte paste is employed to prepare QS-sub-module cells. The four strip and rectangular-shaped module cells have high efficiencies of 4.71% and 4.81%, respectively. QS-DSSCs using 1 wt.% SiO2 nanofillers show high stability at both room temperature and 60 °C.
查看更多>>摘要：? 2021 The Korean Society of Industrial and Engineering ChemistryThe extracellular matrix (ECM) is the non-cellular component that exists in all tissues and provides dynamic microenvironment that initiates crucial biochemical and biophysical cues, including cell adhesion, proliferation, migration, and differentiation. Although the cell-derived ECM mimics the native cellular microenvironment, the long-term maintenance of cells is required to harvest a sufficient amount of ECM for the intended application. In this study, we evaluated the biophysical properties of fucoidan as a macromolecular crowding (MMC) agent to accelerate ECM synthesis and deposition in human dermal fibroblasts and found that the accumulated cell-derived ECM by fucoidan (fCDM) influenced the osteogenic differentiation of mesenchymal stem cells (MSCs). The treatment of fucoidan resulted in significantly higher ECM deposition at 5 days compared with the treatment of dextran sulfate (DxS), a potent MMC agent. The advantages of fCDM were demonstrated in vitro by the promotion of multiple cellular behaviors of MSCs, osteogenic differentiation, and signal transduction pathway. In addition, the PLGA scaffold containing fCDM had significantly higher alkaline phosphatase activity than the PLGA scaffold containing acellular bone tissue ECM. Based on these results, the fCDM can support the development of human cell-derived, xeno-free biomaterials for tissue engineering applications.
查看更多>>摘要：? 2021 The Korean Society of Industrial and Engineering ChemistryCarbon based conductive polymer composites as electrothermal materials offers many merits in high flexibility, light weight, low cost, excellent processability, and rapid heating ability, however, the maximum working temperature is usually lower than 200 °C, hampering seriously the medium–high temperature applications. Herein, a series of rationally designed glass fiber reinforced graphite/carbon black@polyethersulfone (G/CB@PES) composites are developed to significantly promote the maximum working temperature over 300 °C. To be specific, the introduced glass fibers acted as rigid skeleton greatly enhance the mechanical strength of PES polymer matrix, thereby offering robust structural stability in high temperature working scenario. Meanwhile, glass fibers not only endow G/CB@PES composite with excellent flame-retardant ability, but also provide rapid thermal conduction channels to reduce the risk of heat accumulation and overheating. More importantly, glass fiber reinforced G/CB@PES composites as electrothermal film heaters exhibit superior electric heating performance in terms of fast temperature responsiveness, high electric heating efficiency, stable maximum working temperatures, and high electric power efficiency under the relatively low applied voltages of 3–21 V. This work provides new insights on the innovative design and facile fabrication of high working temperature electrothermal film heaters in emerging applications.
查看更多>>摘要：? 2021 The Korean Society of Industrial and Engineering ChemistrySilver nanowire (AgNW) networked films have received much attention as transparent conducting materials owing to their excellent conductivity, high transmittance, and moderate cost. In addition, AgNWs can be easily prepared as dispersions in liquids, enabling solution-based processing. Nevertheless, the fabrication of highly transparent AgNW networked electrodes remains challenging owing to the high percolation threshold of AgNWs. In this study, web-like AgNW networked films were fabricated via the dewetting-driven self-assembly of AgNWs using meniscus-dragging deposition. The dewetting of liquid thin films containing AgNWs was finely tuned by adjusting the ethylene glycol content of an AgNW–isopropyl alcohol dispersion and the surface energy of the coating substrate. The obtained AgNW networked electrodes with self-assembled web-like structures had a significantly lower percolation threshold (0.26 μg cm?2) than randomly networked AgNW electrodes (2.53 μg cm?2), resulting in an outstanding combination of sheet resistance and optical transparency (38 Ω sq?1 at T = 96%). This large scalable one-step coating strategy for metal mesh thin films can advance the development of next-generation transparent conducting electrodes.
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