FLUID PHASE EQUILIBRIA
·
2010
·Vol. 293
·期 1
·73-78
·
IF 1.857
Song Hu,Qing-lin Chen,Bing-jian Zhang,Yuan-lan Liang,Xue-nong Gao
Experimental liquid–liquid equilibrium (LLE) of the water–acetic acid–sec-butyl acetate ternary system was investigated at 298.15, 303.15, 308.15 and 313.15 K and at atmospheric pressure. Separation factors were also evaluated for the immiscibility region. The NRTL and UNIQUAC models were applied to fit the experimental data for the ternary system . The binary interaction parameters obtained from both models were found to be successfully correlated with the equilibrium compositions . The UNIFAC group contribution method was employed to predict the observed ternary LLE data. It was found that four types of the UNIFAC model (UNIFAC, UNIFAC-LL, UNIFAC-DMD, and UNIFAC-LBY) did not provide a good prediction of the LLE data for this ternary system .
研究领域:
化学工程
·
热力学
·
分离科学
·
过程工程
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DOI
高影响因子
AGRICULTURAL RESEARCH
·
2024
·Vol. 13
·期 2
·198-203
·
IF 1.4
Lv Na,Li Li,Wang Na,Guo Chang-jie,Zhang Hao-yan
Snap bean ( Phaseolus vulgaris L.) is very sensitive to low temperature during postharvest storage. Methyl jasmonate (MeJA) is a volatile hormone ubiquitous in many kinds of plants and plays important role in regulating plant physiological functions. The alleviating effect of MeJA treatment on chilling injury (CI) in postharvest snap bean was studied. We found MeJA treatment markedly decreased the index of chilling injury, electrolyte leakage and content of malondialdehyde. MeJA-treated snap bean exhibited higher levels of total soluble solids and titratable acidity. Similarly, MeJA could prevent the degradation of chlorophyll and ascorbic acid. Not only total antioxidant capacity but also metal chelating ability of MeJA-treated snap bean was stronger than untreated control. MeJA-treated snap bean showed higher scavenging activities on superoxide radical (O 2 .- ), hydroxyl radical (·OH) and 1,1-diphenyl-2-trinitrophenylhydrazine radical either. MeJA application stimulated the activities of ascorbate peroxidase (APX), peroxidase (POD), superoxide dismutase (SOD) and catalase (CAT) in snap bean. In conclusion, this study reveals MeJA can be used to relieve chilling injury and maintain the quality of snap bean during low-temperature storage. 8 µM MeJA is the optimal concentration to alleviate chilling injury of snap bean.
研究领域:
植物学
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植物生理学
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采后生物学
·
食品科学
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DOI
高影响因子
Journal of Coatings Technology and Research
·
2019
·Vol. 16
·期 5
·1305-1316
·
IF 1.584
Shi Hongyi,Liu Weiqu,Liu Chunhua,He Sha,Jiang Chi,Wang Zhengfang
Monomethacryloyloxy-terminated fluorinated oligomers (PPFOMA-GMA and PHFBMA-GMA) and methyl allyl alcohol polyoxyethylene ether-modified epoxy resin (HPEGEA) were successfully synthesized and used as reactive additives and emulsifier for epoxy acrylate, respectively. FTIR, 1 H NMR, and GPC were used to characterize the structures of PPFOMA-GMA, PHFBMA-GMA, and HPEGEA. The influence of the concentrations of PPFOMA-GMA and PHFBMA-GMA on the properties of waterborne epoxy acrylate (WEA) resin coatings was investigated. The surface energy of waterborne epoxy acrylate coating was decreased from 38.20 mN/m to 15.31 mN/m by adding just 0.21 wt% PPFOMA-GMA, indicating its high effectiveness in improving the hydrophobic properties of the surface. The surface compositions of the WEA resin coatings (with 0.85 wt% PPFOMA-GMA or 0.85 wt% PHFBMA-GMA) were characterized by XPS. The XPS results confirmed the quantitative enrichment of fluorine atoms on the surface. What is more, the physical properties of waterborne epoxy acrylate coatings prepared with different concentrations of fluorinated reactive additive, such as optical transmittance, adhesion (on glass, PET, and tinplate), pencil hardness, water absorption, and thermal properties, were also analyzed in detail. Hence, the waterborne epoxy acrylate coatings prepared with low concentrations of reactive additives were economical and have potential for large-scale industrial applications.
研究领域:
高分子化学
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材料科学
·
表面工程
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DOI
高影响因子
FirePhysChem
·
2021
·
IF 0
Qi Xue,Fuqiang Bi,Junlin Zhang,Jiarong Zhang,Bozhou Wang,Minjie Wu
Two novel energetic compounds, 3-nitroxymethyl-5-(4-nitro-furazan-3-yl)-1,2,4-oxadiazole ( 4 ) and 3-nitroxymethyl-5-(4-azido-furazan-3-yl)-1,2,4-oxadiazole ( 5 ), were synthesized. Both of them were fully characterized, and the structure of 4 was further confirmed by X-ray single crystal diffraction. The thermal behaviors, detonation performances and the sensitivities of 4 and 5 were also investigated by differential scanning calorimetry (DSC), EXPLO5 program and BAM standard techniques. In addition, the electrostatic potential energy surface (ESP) was studied by Multiwfn program and density functional theory at B3LPY/6-31G (d, p). Both compounds have low melt-point, good energetic performance and mechanical sensitivity, which endow them with promising properties as plasticizing ingredients in propellant formulations.
研究领域:
有机化学
·
含能材料
·
晶体结构
·
热分析
✓ 已验证
DOI
Applied Catalysis O: Open
·
2024
·
IF 0
Huajun Wang,Jingjing Ma,Yan Li,Tengfei Wang
A series of deep eutectic solvents (DESs) with ZnCl 2 as hydrogen bonding acceptor and monoethanolamine (MEA) or acetamide as hydrogen bonding donor were prepared and used as catalysts for the reaction of glycerol and urea to synthesize glycerol carbonate (GC) without any additional organic solvent and co-catalyst. FT-IR, TGA, DSC and pH value were used to characterize the physicochemical properties of the prepared DESs. The effect of reaction temperature, urea to glycerol molar ratio, catalyst amount, and reaction time on the reaction were further investigated. The results show that ZnCl 2 :Acetamide (1:2) DES possess the highest catalytic activity because of the strong hydrogen bond network between ZnCl 2 and acetamide and the hydrogen bonding interactions between ZnCl 2 :Acetamide (1:2) and reactants, which were shown by FTIR spectra. The glycerol conversion of 93.85 % and GC yield of 90.77 % were obtained at reaction temperature of 140 °C, urea to GL molar ratio of 1:1, catalyst amount of 5 wt% (based on the GL weight) and reaction time of 2 h. Based on the experimental results and characterization by FTIR and ESI-MS, the reaction mechanism was proposed.
研究领域:
催化化学
·
绿色化学
·
有机合成
✓ 已验证
DOI
JOURNAL OF POLYMERS AND THE ENVIRONMENT
·
2024
·
IF 4.7
Wang Guoqiang,Hui Yunfeng,Wei Deyu,Wang Yueying,Yu Yiheng,Shi Longqing,Zhang Mengke,Hu Jing
Poly(butylene succinate) (PBS), a biodegradable material, has excellent mechanical properties and processing properties. Brassylic acid (BA) is a kind of diacid with long chains derived from biomass. In this study, poly(butylene succinate-co-butylene brassylate) is synthesized to investigate the effects of BA on the structure and properties of PBS. The relationship between the melting temperature of copolyesters and the content of butylene brassylate units is V-shaped, which is typical of isodimorphic random copolyesters. Due to the introduction of BA, the density of unstable ester bonds in copolyesters gradually decreases and the initial thermal decomposition temperature of copolyesters gradually increases with the increase of BA. The dynamic mechanical analysis showed that the glass transition temperature of PBS was reduced by the introduction of BA. When the BA content is 25%, the copolyesters and PBS have the same crystal structure. When the BA content is 50–100%, the copolyesters and poly(butylene brassylate) have the same crystal structure, which indicates that the butylene brassylate units are easier to crystallize than the butylene succinate units. The ductility of copolyesters increases with the addition of BA. When the BA content is 50%, the elongation at break reaches the maximum (> 2000%). The copolyesters are suited for films due to high elongation at break.
研究领域:
材料科学
·
生物化学
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DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2018
·
IF 3.141
Ming Zhang,Wenqin Lai,Lili Su,Guozhang Wu
The effects of catalyst on the molecular weight, chemical structure, and yellowness of isosorbide-based polycarbonate (ISB-PC) in the melt-transesterification and polycondensation stages were investigated. Results showed that the high steric hindrance and intramolecular hydrogen bonding of the endohydroxyl group (endo–OH) of ISB enabled its reactivity to be lower than that of the exohydroxyl group (exo–OH). We also found that the reactivity of endo–OH with diphenyl carbonate can be preferentially activated by strong electrophilic catalysts, and that the configuration of the ISB-PC chain strongly depended on the reactivity balance between endo–OH and exo–OH. Various catalysts with different coordinate capacities, acidity coefficients, and radius of metal ion were further tested. Catalysts with a calcium or zinc ion showed a higher reactivity of endo–OH than exo–OH, resulting in a high glass-transition temperature of ISB-PCs. Results suggested as well that the thermal stability of ISB-PC may be correlated to the amount of OH groups at the chain ends, whereas its yellowness mainly arose from 1,4-sorbitan due to the hydrolysis of ISB.
研究领域:
材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2020
·
IF 7.489
Yue Wei,Yanping Xie,Zhixiang Cai,Yalong Guo,Min Wu,Pengguang Wang,Ruiqi Li,Hongbin Zhang
Hypothesis The structural modification of natural emulsifiers may greatly impact their interfacial behaviours and bulk properties. The relationship between the microscopic interfacial viscoelasticity and the macroscopic emulsion stability in emulsifiers with different degrees of modification can be clarified using a multiscale approach. Experiments A polysaccharide emulsifier of corn fibre gum (CFG) with different octenyl succinate anhydride (OSA) contents was used to obtain a broad variety of interfacial properties . Interfacial adsorption kinetics and viscoelastic responses were measured by combining interfacial shear rheology and quartz crystal microbalance with dissipation monitoring, and the emulsion properties (droplet size and physical stability) at other scales were evaluated. Findings Compared with native CFG, esterified CFG formed thick interfacial films with higher elasticity and viscosity , and their corresponding emulsions showed greater stability. There exists a satisfactory correlation between interfacial rheological properties and emulsion stability. However, such a satisfactory correlation can not be established among the degree of esterification of CFG, interfacial viscoelasticity and stability since depletion flocculation might occur in the emulsion stabilized by the OSA-CFG with the highest OSA content, which induced inferior bulk stability but exerted no impact on the measured interfacial properties. We propose that the depletion flocculation is responsible for this imperfection and provide detailed explanations.
研究领域:
食品科学
·
胶体化学
·
表面化学
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DOI
高影响因子
JOURNAL OF FOOD SCIENCE
·
2021
·Vol. 86
·期 8
·3550-3562
·
IF 3.167
Ying Cai,Jingwei Guan,Wen Wang,Li Wang,Jianyu Su,Liming Fang
Food packaging materials, especially biodegradable polymer composites incorporated with natural antimicrobial agents with excellent antibacterial activities, are in high demand and attracted immense attention. Herein, a polycaprolactone/curcumin@zeolitic imidazolate framework-8 (PCL/Cur@ZIF-8) composite film with enhanced antibacterial activity was developed. Curcumin, a natural photosensitizer, was loaded in the highly porous nanocrystals ZIF-8 to improve its poor water solubility and stability. The integral structure of Cur@ZIF-8 was maintained well in the PCL matrix even at the highest loading of 35% (w/w), and all composite films had good light transmittance at 420–430 nm. The PCL/Cur@ZIF-8 composite films responded to the acidic growth environment of bacteria by releasing zinc ions and curcumin molecules. Furthermore, upon blue light irradiation (420–430 nm, 2.2 mW/cm 2 ), curcumin molecules generated singlet oxygen. With the synergistic effects of zinc ions and singlet oxygen, the composite films exhibited a 99.9% reduction of Escherichia coli and Staphylococcus aureus strains when the amount of Cur@ZIF-8 loading was more than 15% (w/w), as well as a strong anti-adhesion effect on bacteria. Moreover, bacterial resuscitation tests indicated that the composite films exhibited 99.9% reduction in the adhered bacteria population through treatment with photodynamic sterilization. This is the first study presenting that the incorporated curcumin ZIF-8 nanoparticles in the matrix of polymer are pH and light responsive for anti-adhesion of bacteria, which is of great potential application as antibacterial packaging material for the food industry. Practical Application A novel, biodegradable, pH, and light-responsive composite film was developed for antibacterial activity. Natural photosensitizer curcumin was encapsulated in ZIF-8 nanocrystals (Cur@ZIF-8) as the antimicrobial agent. With the synergistic effects of Zn 2+ and singlet oxygen, the composite film exhibited a 99.9% reduction of Escherichia coli and Staphylococcus aureus strains, and a strong anti-adhesion property toward bacteria. This composite film is of great potential application as an antibacterial packaging material that enhances the shelf life of fruits, meat, and so on.
研究领域:
食品科学
·
材料科学
·
生物医学工程
✓ 已验证
DOI
高影响因子
CHEMICAL ENGINEERING RESEARCH & DESIGN
·
2020
·
IF 3.35
Shaojian Hu,Jianhua Zhu,Bencheng Wu,Rui Ma,Xiaohui Li
As an eco-friendly lubricant base oil, ester base oil is receiving increasing attention. However, studies on synthetic reaction kinetics of high viscosity complex ester have been rarely reported. In this work, based on the principle of equal reactivity of all functional groups and simplified kinetics models, synthetic reaction kinetics for high viscosity complex ester was investigated in two steps. As for the esterification of trimethylolpropane with glutaric acid, the activation energies of the first and second stage were 55.3 and 73.5 kJ/mol, respectively. As for the esterification of the first step products with 2-ethylhexanoic acid, the activation energies of the first and second stage were 60.6 and 98.2 kJ/mol, respectively. As for the esterification of the first step products with n -heptanoic acid, its activation energy was 68.9 kJ/mol. A mutation phenomenon on reaction order from zero to second order was discovered, which could be explained by the strong adsorption of organic acid on catalyst surface. The conversion rate of carboxyl of synthetic reaction for mixed acid ester was estimated by simulation, and average relative error was less than 3.0%. The synthetic process of high viscosity complex ester was considered to consist of a series of parallel–consecutive reactions with addition–elimination mechanism.
研究领域:
化学工程
·
环境科学
✓ 已验证
DOI
高影响因子
POLYMER
·
2022
·
IF 4.432
Yiliang Gao,Yumin Wu,Jingming Zhao,Ying Ma,Yuetao Liu,Chuanhui Gao
Focusing on the self-assembly strategy of polymer chain structure, designing and synthesizing intelligent, tough and healable polymer materials is an effective way to meet the high-end applications of materials. Inspired by spider silk, we designed a preparation scheme for a repairable polyurethane-polyurea elastomer (IPAD-6.4) with an unprecedented mechanical toughness of 625.10 MJ/m 3 and elongation at break of 3756.56%. After repeated cyclic stretching, the elastic body can recover 92.85% of the dissipated energy in only 2 h. These results are achieved by the hierarchical hydrogen bonds formed by different groups and the reasonable covalent cross-linking network. Additionally, the elastomer shows excellent healing ability (repair efficiency ∼102.77%). A flexible conductive composite film is prepared by simple physical assembly. The sensor can not only accurately detect the bending motion of human joints, but also has excellent antibacterial properties, which gives the material application potential in medical and engineering fields.
研究领域:
材料科学
·
生物医学工程
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DOI
高影响因子
LETTERS IN ORGANIC CHEMISTRY
·
2023
·Vol. 20
·期 4
·370-375
·
IF 0.8
Chai Mengliang,Wu Fengtian,Wu Ling
The process of hydrogen bond donor accelerating the cycloaddition of epoxides with CO2 is green access to high economic value cyclocarbonate derivatives. However, hydrogen bond donor still has certain limitations such as poor biocompatibility and narrow substrate
scope. Our group found that folic acid could promote the coupling reaction of epoxides and CO2 through hydrogen-bonding. The reaction was used to synthesize various cyclocarbonate derivatives in good to high yields with the aid of folic acid and TBAB. In addition, benzoic
acids and 2,4-quinazoline dione were synthesized in the presence of CuCl2/folic acid and PdCl2/folic acid, respectively. The reaction mechanism was proposed based on previous reports and control experiments.
研究领域:
化学
·
环境科学
·
材料科学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）