查看更多>>摘要：? 2022 The Korean Society of Industrial and Engineering ChemistryNew SA-g-P(AAc-co-MA)/TiO2 nanocomposite was synthesized using the free radical graft copolymerization technique. The synthesized nanocomposite was characterized using FTIR, FE-SEM, XRD, TEM, TGA, and BET techniques. It was then utilized as an adsorbent for removing the Brilliant green (BG) dye from an aqueous solution. The effect of different factors like the initial concentration of the BG dye, pH of the solution, and temperature have been studied. The experimental results were analyzed via the isotherm Freundlich and Langmuir adsorption models. To have deep insight into the adsorption mechanism, the density functional theory (DFT) method was used. According to the analyses, the equilibrium results fitted completely with Freundlich isotherm; thus, the pseudo-first-order and pseudo-second-order kinetics and intra-particle diffusion models were utilized to determine the adsorption kinetic result. The optimal conditions for the studied parameters which revealed the highest adsorption were: T = 30 °C, pH = 3, ΔGo = ?6.87 kJ.mol?1, ΔHo = 15.788 kJ.mol?1, and ΔSo = 93.92 J.mol?1.K?1. The kinetics adsorption was consistent with the pseudo-second-order kinetic model, and the above-mentioned thermo-dynamics variables, ΔGo, ΔHo, and ΔSo, suggested that the adsorption of Brilliant green dye on synthesized nanocomposite was spontaneous and endothermic.
查看更多>>摘要：? 2022 The Korean Society of Industrial and Engineering ChemistryPyrolyzing carbon precursors will also lead to a large amount of exhaust gas, which is a waste of resources and a huge pollution. Therefore, realizing the full utilization of exhaust gas from carbon precursors is significant. Herein, cobalt (Co) modified hard templates with micropores or mesopores is used to prepare porous carbon for supercapacitors, in which Co species provide the active sites for the capture and deposition of exhaust gas derived from zeoliticimidazolate framework. Using N2 as protective and carrier gas, the whole process can be realized in a simple tubular furnace. The obtained PC can replicate the morphology and pore structure of the hard template with the characteristics of micropores or mesopores respectively. The microporous structure of PC gives it higher surface area and pore volume than PC with mesopores, which makes it have high capacitance of 445.7 F g?1 in supercapacitor.
查看更多>>摘要：? 2022 The Korean Society of Industrial and Engineering ChemistryCastor oil based polyurethanes were reinforced with cellulose nanofibers derived from hemp and graphene nanosheets to yield hybrid nanocomposites using ultrasonication coupled with high shear homogenization. Morphology of nanocomposites assessed using transmission electron microscopy (TEM) and field emission scanning electron microscopy (FESEM) elucidated 3D network of CNFs and GNS in polyurethane matrix. The paramount properties were obtained with equal amounts of CNFs and GNS attributed to higher degree of crystallinity. Thermal stability was evaluated using Thermogravimetric analysis (TGA) and Differential Scanning Calorimetry (DSC), which exhibited a substantial increase in peak degradation temperature by 24 °C and glass transition temperature by 36 °C, with mere addition of 1% CNFs and GNS each. The mechanical properties improved by more than 400% attributed to the presence of interconnecting network of GNS and CNFs, initiating enhanced interactions amongst polymer and nanofillers, established by X-Ray photoelectron spectroscopy (XPS). Strong intermolecular bonding between the fillers and the polymer matrix reduced the phase separation, facilitating migration of soft segments to the surface increasing the water contact angle by 32°. The decrease in surface energy and work of adhesion contributed to hydrophobicity of nanocomposites. The improved properties of hybrid nanocomposites ascertain their potential applications in protective coatings and automobile parts.
查看更多>>摘要：? 2022 The Korean Society of Industrial and Engineering ChemistryTo improve the low crystallization rate and long molding cycle of Poly(ethylene terephthalate) (PET), series of PET nanocomposites incorporated small quantities of zeolites with different topologies were blended by melt compounding. The nucleation influence of 3-dimensional zeolites Y, ZSM-5 and 2-dimensional zeolite MCM-22P on the crystallization manner of PET was analyzed by non-isothermal and isothermal crystallization, quantitative evaluation of nanoparticle dispersion and morphology of nanoparticles. The results show that all PET/zeolite nanocomposites exhibit higher crystallization temperature and faster crystallization rate than PET due to large specific surface area of zeolites and their superior dispersion in the PET matrix. Among them, PET/MCM-22P nanocomposites remarkably improved the crystallization behavior, thermal stability and oxygen barrier properties, which is related to the layered morphology of MCM-22P and hydrogen bond interactions between MCM-22P and PET. It is revealed that MCM-22P can provide more heterogeneous nucleation sites for PET by exfoliation in melting compounding. Furthermore, the nucleation mechanism induced by MCM-22P was investigated by the means of Mozhishen method, Avrami equation and theory of Hoffman-Lauritzen. The results indicate that the incorporation of MCM-22P can decrease the free energy of nucleation and fold surface in PET crystallization process, thus improving the crystallinity.
查看更多>>摘要：? 2022 The Korean Society of Industrial and Engineering ChemistryThe commercial application of silicon (Si) anodes with high theoretical capacity is hampered by the poor cyclic stability because the huge volume change of Si during discharge/charge processes results in the pulverization of electrode materials and the electric contact loss of electrode materials with copper (Cu) foils. Binders play an important role for adhering active materials and conductive additives together onto Cu foils. Herein, we design and develop a three-dimensional networked composite binder (PAA-co-SN) via an amidation reaction between polyacrylic acid (PAA) and thiourea (SN). The granular anchors (CuxS) are constructed at the interface between PAA-co-SN binders and Cu foils, resulting from the reaction of S and Cu during the drying processes of Si electrodes. When used as binders for Si nanoparticles, they exhibit stable cyclic performance (1580 mAh g?1 after 500 cycles). The anchoring mechanism between composite binders and Cu foils provides a strategy for the improvement of electrochemical properties of Si-based anodes for lithium-ion batteries.
查看更多>>摘要：? 2022 The Korean Society of Industrial and Engineering ChemistryThe graphene patterns with piezoresistance behaviors, originating from the structural deformation and band-structure shift under strain, represent an attractive characteristic for developing the small strain (<10%) sensors for wearable devices. However, the insufficient adhesion between the patterns and substrates has significantly limited their utility and reliability. Here, the surface-embedded graphene patterns were directly deposited on polydimethylsiloxane (PDMS) surfaces without hydrophilic treatment via the embedded droplet printing (EDP). The viscous PDMS films instead of the solid ones were used as substrates, and the graphene patterns were partly embedded onto the viscous PDMS surfaces. To assess the adhesion performance, a series of tests were performed. In the bending and tensile tests, the patterns strongly adhered to the PDMS films. Further, the patterns had a favorable increase in resistance in the tensile strain range of 0–3.5%. The resistance of the surface-embedded graphene patterns exhibited a negligible change for over 3 min in the ultrasonic bath. Finally, the relative resistance R/R0 remained constant after the first two adhesion tests using a 3M tape. The surface-embedded graphene patterns exhibited a strong adhesion to the flexible/stretchable substrates, indicating the application prospect in the field of flexible devices.
查看更多>>摘要：? 2022 The Korean Society of Industrial and Engineering ChemistryThe application of conventional absorbing materials is limited due to complex preparation process and poor transparency caused by fillers. In this study, a highly transparent ionic organogel was prepared by photocuring a dimethyl sulfoxide (DMSO) solution of a polymerizable magnetic cationic monomer [DAC]5[Dy(NCS)8]. Both components of organogel, which are the photopolymerizable magnetic cationic monomer and polar solvent DMSO, have an important effect on the magnetic losses and dielectric losses properties of the organogel respectively. By tuning the mass ratio of DMSO to the monomer and the content of the cross-linker, the complex permittivity of the gel could be effectively adjusted to improve the impedance matching, and finally a gel with excellent wave absorption properties and good tensile properties was obtained. The optimum organogel was fabricated with a minimum reflection loss of ?45.9 dB and a broadest effective absorption bandwidth (EAB) of up to 5.2 GHz, and effective absorption in the millimeter band (26.5–40 GHz) which is within the fifth generation (5G) mobile networks. With the advantages of simple preparation method, arbitrary shape and good adhesion to a variety of substrates and complex surfaces, this multifunctional gel provides a new solution for complex scenarios requiring optical transparency and simultaneous absorption of electromagnetic waves.
查看更多>>摘要：? 2022 The Korean Society of Industrial and Engineering ChemistryRed ginseng marc (RGM), a byproduct obtained during manufacturing various ginseng products, which is typically discarded as waste, contains numerous residual bioactive compounds. However, the recovery of bioactive compounds, including transformed ginsenosides, from RGM using conventional extraction techniques is difficult. In this study, subcritical water was used for a quick and high-yield extraction of the bioactive compounds in RGM. Furthermore, the chemical species and antioxidant activities of the extracts were analyzed. Extraction was performed in the temperature range and duration of 140–200 °C and 15–90 min, respectively, to determine the optimal conditions for achieving the highest extraction yield and bioactivity. Under the optimized conditions (200 °C and 15 min), an extraction yield of 48 wt% was achieved, which was 1.8 and 4.1 times higher than those achieved via Soxhlet extraction with water and 80% ethanol, respectively (8 h). In addition, the antioxidant activity of the subcritical water extract was 2.7–78.7 times and 2.8–9.8 times higher than those of the extracts obtained using the Soxhlet method with water and 80% ethanol, respectively. The total ginsenoside content of the extract was 30 mg/g, and G-Rf, a transformed ginsenoside, was the primary component of the extract.
查看更多>>摘要：? 2022 The Korean Society of Industrial and Engineering ChemistryIn this study, a green and efficient ultrasound-assisted enzymatic extraction (UAEE) method was established for total polyphenols (TPP) extraction from E. nigrum aerial parts. Fractional Factorial design (FFD) was initially implemented for the selection of significant parameters affecting TPP yield and then Box-Behnken design-response surface methodology (BBD-RSM) was employed to optimize the parameters. The optimum extraction conditions for UAEE were as follows: incubation temperature of 38.39 ℃, incubation time of 3.39 h, tannase of 386.53 U/g of sample (U/g), and cellulase of 224.42 U/g. Under the optimum conditions, the TPP yield was 52.17 ± 0.39 mg/g, which was 1.62 and 1.73 times those of the methods of ultrasound-assisted extraction (UAE) and enzyme-assisted extraction (EAE), respectively. The crude extract was purified by HPD-600 microporous resin, and the purity was improved from 8.11% to 22.56%. In addition, the results of antioxidant and antibacterial activity assays showed that the purified extract has stronger bioactivities in contrast with the crude extract. This study indicated that UAEE was an effective technique for the extraction of TPP from the aerial parts of E. nigrum, and TPP extracted by this extraction method could be applied in pharmaceuticals, cosmetics, and food industries.
查看更多>>摘要：? 2022 The Korean Society of Industrial and Engineering ChemistryNovel poly(vinylidene fluoride) (PVDF) ultrafiltration membranes blending with chiral mesoporous SiO2 materials were constructed to improve the anti-fouling and separation performance of PVDF-blended membranes. The formation of asymmetric mesoporous structure of chiral mesoporous SiO2 caused their large hydrophilic surface and significant chiral features, which enhanced the hydrophilicity and polarity of the resulting PVDF membranes blended with chiral mesoporous SiO2. So, the PVDF-blended membranes containing chiral mesoporous SiO2 had a high permeation performance and anti-fouling property. After blending with chiral mesoporous SiO2, the maximum flux of membranes exceeded 500 L·m?2·h?1 and was 6.5-fold higher than that of neat PVDF. Due to the stereo-specific interaction between enantiomers and chiral recognition sites introduced by chiral mesoporous SiO2 in the membranes, all PVDF-blended membranes had evident enantioseparation performance for DL-racemic tryptophan. The C-SiO2-20/PVDF-blended membranes had the highest enantioseparation performance under the same addition content and the maximum enantiomeric excess (e.e.%) was more than 20 %. Given the strong stereo-specific interaction and hydrogen bonding between d-tryptophan and β-cyclodextrin (β-CD), the addition of more β-CD would introduce more chiral recognition sites into the membranes, thereby enhancing the enantioseparation performance of the membranes for d-tryptophan. The maximum e.e.% of C-SiO2-20/β-CD/PVDF-blended membranes for the tryptophan enantiomer reached 55%.
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