Polymers
·
2020
·Vol. 12
·期 2
·424
·
IF 3.426
Yicheng Zeng,Yang Liu,Lumin Wang,Hongliang Huang,Xun Zhang,Yongli Liu,Minghua Min,Ying Li
Silver (Ag) nanoparticles were synthesized by a facile route in the presence of oleic acid and n-propylamine. It was shown that the average primary size of the as-synthesized Ag nanoparticles was approximately 10 nm and the surface of as-synthesized Ag nanoparticles was capped with monolayer surfactants with the content of 19.6%. Based on as-synthesized Ag nanoparticles, polyoxymethylene (POM)/Ag nanocomposites were prepared. The influence of Ag nanoparticles on non-isothermal crystallization behavior of POM was investigated by differential scanning calorimetry (DSC). The Jeziorny, Jeziorny-modified Avrami, Ozawa, Liu and Mo, Ziabicki and Kissinger models were applied to analyze the non-isothermal melt crystallization data of POM/Ag nanocomposites. Results of half time (t1/2), crystallization rate parameter (CRP), crystallization rate function (K(T)), kinetic parameter (F(T)), the kinetic crystallizability at unit cooling rate (GZ) and the crystallization activation energy (∆E) were determined. Small amounts of Ag nanoparticles dispersed into POM matrix were shown to act as heterogeneous nuclei, which could enhance the crystallization rate of POM, increase the number of POM spherulites and reduce POM spherulites size. However, the higher loading of Ag nanoparticles were easily aggregated, which restrained POM crystallization to some degree. Furthermore, the POM/Ag nanocomposites showed robust antibacterial activity againstEscherichia coliandStaphylococcus aureus.Keywords:POM;Ag nanoparticles;POM/Ag nanocomposites;non-isothermal crystallization kinetics;heterogeneous nuclei;antibacterial activity
研究领域:
材料科学
·
高分子化学
·
纳米技术
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生物医学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
RSC Advances
·
2015
·Vol. 5
·期 47
·37697-37702
·
IF 3.84
Liuyi Yin,Yufeng Hu,Xianming Zhang,Jianguang Qi,Weiting Ma
Batch reaction experiments were performed to investigate the salt effect on the yield of trioxane in the reaction solution. The salts considered include NaHSO4, Na2SO4, NaH2PO4, Na2HPO4, KCl, NaCl, LiCl, ZnCl2, MgCl2, and FeCl3. The effects of the anionic structure and the cation charge density on the yield of trioxane in the reaction solution were elucidated and the mechanisms that govern such effects were established. It is shown that the first four salts exerted a negative effect on the yield of trioxane in the reaction solution and such an effect increased progressively from left to right. This trend is due to the formation of NaHSO4, H3PO4, or (H3PO4 and NaH2PO4), which decreased the concentration of H+ in the solution. The latter six salts showed a positive effect on the yield of trioxane in the reaction solution. The salt effect paralleled the ability of the salt to decrease the water activity of the reaction solution and followed the order KCl < NaCl < LiCl < ZnCl2 < MgCl2 < FeCl3. Continuous production experiments were performed to investigate the salt effect on the concentration of trioxane in the distillate. The salts considered were KCl, NaCl, LiCl, ZnCl2, MgCl2, and FeCl3, and the salt effect increased progressively from left to right. Such an effect was shown to be determined by the ability of the salt to increase the yield of trioxane in the reaction solution and to increase the relative volatilities of trioxane and water and of trioxane and oligomers.
研究领域:
化学工程
·
工业化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS
·
2023
·
IF 6
Geliang Xie,Guoqiang Zhu,Tong Lv,Yifan Kang,Yuhan Chen,Zhen Fang,Lujiang Xu
Co-valorization of biomass and multiple solid wastes is essential to environment protection and energy security. Herein, aromatic-rich biofuel was produced from lignin and waste polyoxymethylene (POM) via catalytic co-pyrolysis process. Commercial and cheap γ-Al 2 O 3 catalyst exhibited good catalytic performance. Series characterizations and bench-top pyrolysis experiments were conducted to illustrate the synergism between raw materials and the mechanism of aromatics formation. The TG analysis and thermodynamics calculation revealed that a remarkably positive synergistic effect existed between lignin and POM, which reduce the activation energies and make the reaction more conducive in terms of thermodynamics. Meanwhile, the yields of biochar and bio-oil increased considerably. Additionally, the operating conditions affected the product distributions significantly. The suitable mixing ratio of lignin to POM was around equal (5:5) with the bio-oil yield increased to 28.3 % and aromatic hydrocarbons selectivity increased to > 95 %. Moreover, POM, the precursor for alkylating reagents and hydrogen donors , could promote the deoxygenation reactions of phenolic intermediates and result into aromatic hydrocarbons. The acid sites of γ-Al 2 O 3 promoted series secondary cracking reactions (alkylation, deoxygenation), and thus improved bio-oil quality. Finally, the stability test showed that commercial γ-Al 2 O 3 catalyst was slightly deactivated after 4 cycles because of coke deposits and acid sites loss.
研究领域:
能源与环境科学
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催化化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF CHEMICAL TECHNOLOGY AND BIOTECHNOLOGY
·
2019
·Vol. 95
·期 3
·719-729
·
IF 2.659
Siqi Jiang,Xianming Zhang,Yufeng Hu,Liuyi Yin,Jianguang Qi,Chunxiao Ren,Shuqin Mo
BACKGROUND Trioxane (C 3 H 6 O 3 ) is industrially produced from aqueous formaldehyde (HCHO) solutions through catalytic distillation catalyzed by sulfuric acid (H 2 SO 4 ). Optimizing industrial process of the synthesis and developing new catalysts require a reliable model for the vapor–liquid equilibria in reaction mixture HCHO–C 3 H 6 O 3 –H 2 SO 4 – H 2 O and a deep understanding of the role of H 2 SO 4 in the industrial production of trioxane. RESULTS Here the Maurer and co-workers's model and the LIFAC model along with their model parameters were invoked to develop such a model. The vapor–liquid equilibrium data in HCHO–C 3 H 6 O 3 –H 2 SO 4 –H 2 O and HCHO–salt–H 2 O were systematically measured and utilized to determine the newly introduced model parameters. The model thus-established provides a reliable method for calculating and predicting the vapor–liquid and chemical equilibria data in HCHO–C 3 H 6 O 3 –H 2 SO 4 – H 2 O and HCHO–salt–H 2 O. CONCLUSIONS The prediction results uncover that, in addition to its ability to accelerate the reaction, the catalyst H 2 SO 4 has strong abilities to increase the activity of ‘real’ reactant for trioxane synthesis and to promote the phase separation that is very important for drastically increasing the yield of trioxane, reducing the energy requirement for the trioxane synthesis, and decreasing the formation of the by-product formic acid. © 2019 Society of Chemical Industry
研究领域:
化学工程
·
工业催化
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF POROUS MATERIALS
·
2024
·
IF 2.5
Wu Wenhui,Zhao Kangrui,Xiao Kun
ZSM-5 is widely used in the field of catalysis due to its stability and tunability. Its acidity can be adjusted not only by varying the initial gel composition, but also by incorporating different types of template to enhance its performance. Both [Ga]-MFI and [Ga, Al]-MFI have demonstrated promising performance in the catalytic trioxane of formaldehyde synthesis. However, there is currently a paucity of research examining the influence of different templates on the catalytic performance of [Ga]-MFI and [Ga, Al]-MFI. The influence of different templates on the structure, morphology, and pore structure of the zeolite has been revealed through the application of characterisation techniques, including XRD, MAS NMR spectroscopy, ICP-OES, BET, and SEM. The impact of different templates on the acid properties of [Ga]-MFI and [Ga, Al]-MFI was assessed using NH 3 -TPD and Py-IR. The results of the experimental investigation into the catalytic performance of zeolites synthesised with larger molecular-structured templates indicate that these zeolites exhibit superior catalytic performance. Furthermore, the introduction of Na + ions has been observed to reduce the space-time yield of the products.
研究领域:
材料科学
·
催化化学
✓ 已验证
DOI
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2018
·Vol. 136
·期 8
·47086
·
IF 1.901
Ruirui Hu,Enlai Gao,Zhiping Xu,Luqi Liu,Guorui Wang,Hongwei Zhu,Zhong Zhang
Two types of electrospun polyoxymethylene nanofibers with rough and smooth surface morphologies [rough fibers (RFs) and smooth fibers (SFs), respectively] were successfully prepared via the control of the electrospinning voltages. Mechanical tensile tests showed that the RF nonwoven mats exhibited a much higher elongation (440%) than the SFs (180%) without sacrifices in the stiffness and strength. Scanning electron microscopy characterization revealed that the large ductility of a single RF resulted from its unique multiple-necking mode, which was induced by its rippled structural features. In the meantime, the large ductility led to a high molecular orientation under tension and further improved the strength and toughness of the RF nonwoven mats. In comparison, the SF behaved in a single-necking deformation mode, and this led to a rapid rupture behavior. This surface-morphology-dependent mechanical behavior helped us to deeply understand the relationship between the structure and properties and should guide the development of high-performance materials for load-bearing applications. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136 , 47086.
研究领域:
材料科学
·
高分子科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF POWER SOURCES
·
2018
·
IF 6.945
Junchen Liu,Kai Yang,Yudi Mo,Shuanjin Wang,Dongmei Han,Min Xiao,Yuezhong Meng
As a pivotal part of lithium-ion batteries, separator is supposed to have high strength , thermal stability and excellent wettability . In this study, polyformaldehyde/cellulose nanofibers blend separators are firstly prepared via thermally induced phase separation to improve the performance, especially the safety of LIBs. The polyformaldehyde/cellulose blend separators show considerable tensile strength (116 MPa) and Young's modulus (6.07 GPa) owing to the high crystallinity and high performance of polyformaldehyde and cellulose . In particular, benefiting from their abundant polar groups and highly porous structure , the polyformaldehyde/cellulose blend separators possess high electrolyte uptake (412%) and small contact angle (19°) as compare to the commercial polyethylene separator (115%, 58°). Moreover, the thermal treatment tests indicate that the polyformaldehyde/cellulose blend separators are thermally stable at as high temperature as 180 °C. And the polyformaldehyde/cellulose blend separators show higher ionic conductivity (1.39 mS cm −1 ) and lower interface resistance (49.5 Ω) than polyethylene separator (0.76 mS cm −1 , 136.4Ω). As expected, the LiFePO 4 /Li cell with polyformaldehyde-20-cellulose blend separators exhibit the best stable cycling performance and improved rate performance than PE separator, especially at high rate. In summary, the polyformaldehyde/cellulose blend separators are promising new kind of separator for LIBs with high safety and enhanced performance.
研究领域:
材料科学
·
能源技术
✓ 已验证
产品关联
DOI
高影响因子
FLUID PHASE EQUILIBRIA
·
2017
·
IF 2.473
Weiting Ma,Yufeng Hu,Haiyan Wang,Di Zhao
Formaldehyde is an important C1 synthon used in the chemical industry. Formaldehyde is mainly used in aqueous solutions. Solid precipitation from these solutions in the form of poly(oxymethylene) glycols impedes many technical processes. Acids, ionic liquids , and salts have been widely used as catalysts and additives in many technical processes using formaldehyde solutions as reactants. Few data are available in literature on solubility of formaldehyde in aqueous solution containing acids, ionic liquids, and salts. In the present work solubility data is reported for temperatures between 58 °C and 87 °C to investigate the effect of typical acids {H 2 SO 4 , H 3 PO 4 , CH 3 SO 3 H, CF 3 SO 3 H, C 6 H 5 SO 3 H, C 7 H 7 SO 3 H, C 8 H 9 SO 3 H, C 10 H 16 SO 4 or H 4 [Si(W 3 O 10 ) 4 ]; the acid concentration is 0.10 mol (kg formaldehyde aqueous solution) −1 }, imidazolium ionic liquids {[mim][HSO 4 ], [mim][CF 3 SO 3 ], [C 3 Smim][CH 3 SO 3 ] or [C 3 Smim][CF 3 SO 3 ]; [mim] + and [C 3 Smim] + stand for 1-methylimidazolium and 1-propylsulfonic-3-methylimidazolium cations; the concentration of the ionic liquid is 0.10 mol (kg formaldehyde aqueous solution) −1 }, and salts [NaCl, KCl, LiCl, MgCl 2 , ZnCl 2 , CH 3 SO 3 Na, CF 3 SO 3 Na, C 6 H 5 SO 3 Na, (C 2 H 5 ) 4 NBr or ZTS (1-methylimidazolium propanesulfonate); the concentration of the former nine salts is 0.40 mol (kg formaldehyde aqueous solution) −1 , and the ZTS concentrations are 0.10 and 0.15 mol (kg formaldehyde aqueous solution) −1 , respectively] on the solubility of formaldehyde in aqueous solutions. The results indicate that most acid catalysts and additive salts considered show salting-out effect. More importantly, the acids and salts that can be used as the catalysts and additive salts for trioxane and have salting-in effect are reported. The influence of the structural characteristics of the acids, ionic liquids and salts that were added on their salting-in/out effect is briefly discussed.
研究领域:
化学工程
·
工业化学
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING SCIENCE
·
2021
·
IF 4.311
Chen Cao,Guilin Liu,Feng Xin,Qian Lei,Xiaofei Qin,Yachen Yin,Honglin Chen,Atta Ullah
Polyoxymethylene dimethyl ethers (PODE n ) are promising diesel blend components with high oxygen content, high cetane number and similar properties to diesel. In this paper, we conducted a series of experiments for synthesizing PODE n over a HZSM-5 catalyst in a batch stirred autoclave using methylal and trioxane as reactants. Our research focused on the water influence on these syntheses by contrasting the differences from experiments with or without water and built reaction pathway and rate laws. The experimental and kinetic results showed that decrease of water amount could not only increase yields of the PODE n but also reduce the influences on formation rates of the desired products and eliminate some side reactions. Therefore, it is necessary to optimize water amount in the raw materials for balancing costs of the feed and operation as well as yields of the products to maximize the economy in a commercial production of PODE n .
研究领域:
化学工程
·
能源科学
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL PAPERS
·
2016
·Vol. 70
·期 11
·1471-1478
·
IF 1.326
Wei-You Zhou,Yong Chen,Yu-Fa Feng,Ming-Yang He,Qun Chen
Alumina-supported potassium (K/Al 2 O 3 ) catalysts using pseudo-boehmite as the precursor were prepared by the impregnation/calcination method, characterised by XRD, SEM, ICP, N 2 adsorption/desorption, CO 2 -TPD methods and TG analysis, and applied to the vapour-phase condensation of methyl propionate with trioxane to produce methyl methacrylate. The results showed the catalysts’ properties to be mainly affected by the calcined temperature ( T C ) and the crystal structure. The sample calcined at 1100°C exhibited the highest catalytic activity when mixed phases were formed and provided the appropriate specific surface area ( S BET ) and surface basic properties. The effects of T C , K-loading and reaction conditions on the catalytic performance were also investigated in a fixed-bed reactor. The yield of methyl methacrylate attained 29.2 % under the optimised conditions, and the deactivated catalyst could be completely regenerated by calcination.
研究领域:
化学工程
·
催化科学
✓ 已验证
DOI
高影响因子
JOURNAL OF MOLECULAR LIQUIDS
·
2021
·
IF 6.165
Yajuan Qu,Yigang Liu,Hongru Zhang,Yasen Dai,Zhaoyou Zhu,Yixin Ma,Jianguang Qi,Yinglong Wang
Polyionic liquids(PILs) have the characteristics of non-volatile, high thermal stability and excellent performance. Because of its strong solubility and molecular recognition ability, it has broad application prospects in the field of azeotropic separation.. In this manuscript, based on COSMO calculation, methylimidazole ionic liquid(ILs) with strong hydrophilic anions was selected as extractant to separate trioxane water and ethanol water azeotropic systems. The screening results were verified by vapor–liquid equilibrium experiments. It was found that [VMIm][DMP] could separate trioxane water and ethanol water azeotropic systems effectively at the same time. In the separation of azeotropes, because the ILs extractant has too strong interaction with H 2 O and the thermal stability is not satisfactory, the recovery energy consumption is high and the heat loss is serious. In this work, [VMIm][DMP] and [VEIm][DEP] were selected as ionic liquid monomers (ILM), and PILs were prepared by the reversible addition-fragmentation chain transfer (RAFT) method. The molecular dynamics (MD) simulation is performed to study the interactions between the solvent molecules and ILs/PILs, in order to investigate the separation mechanism at the molecular level. The study found that increasing the degree of polymerization is beneficial to improve the thermal stability of PILs and relative volatility of trioxane and ethanol, and the influence of degree of polymerization and alkyl side chain length on the hydrogen bond strength of PILs-H 2 O, PILs-trioxane and PILs-ethanol were studied by MD simulation.
研究领域:
化学工程
·
材料科学
✓ 已验证
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2023
·
IF 15.1
Wenbin Jin,Jingjing Wang,Hai Wan,Yuan Liang,Shuohan Huang,Yuwei Chen,Peng Wei,Qun Shao,Yanping Wang,Yong He,Yumin Xia
With the rapid development of marine transportation, frequent oil leakage will inevitably occur. Therefore, oil–water separation had become an important research topic. The polyoxymethylene (POM) microfiber is a potential oil–water separation material with very good chemical stability, hydrophobicity, and lipophilicity, as well as unique microfiber recyclability and deformability. In this paper, the POM microfiber (PMF) was prepared using a method inspired by natural bamboo cellulose. PMF can be directly used for oil adsorption with a maximum of 19.5 times of oil adsorption capacity (OAC). The water contact angle (WCA) in oil of POM microfiber membrane (PMFM) can reach 160° and the oil–water separation efficiency was more than 99%. In addition, the recyclability allowed the PMF to repeatedly separate the oil–water mixture, and the deformability ensured that it can be used in various oil–water separation situations with different shapes. Moreover, only deionized water was used in the top-bottom preparation strategy of PMF without any chemical reagents. Therefore, this eco-friendly strategy had important implications for the preparation of microfiber materials.
研究领域:
材料科学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）