IRANIAN POLYMER JOURNAL
·
2016
·Vol. 25
·期 6
·549-557
·
IF 1.684
Zhang Zhaosheng,Wang Ziwei,Ren Jianguo,Pei Jikai
Acrylic acid–isobutylene polyethylene glycol (AA-TPEG) copolymers are typical of polycarboxylate superplasticizers (PCEs). AA-TPEG copolymers are prepared via free-radical polymerization with potassium persulfate as the initiator. The obtained copolymers were characterized by gel permeation chromatography (GPC) and infrared spectra (FTIR). The GPC method can break through the former limitations of the instruments and receive instantaneous unreacted and instantaneous monomer concentrations and not the initial monomer feeds. Since TPEG monomer is highly bulky, the common calculation methods for determining monomer reactivity ratios in copolymerization based on terminal copolymerization equation are not suitable. However, this study created non-linear least squares curve fitting of terminal copolymerization equation (NLLSQ-T) and penultimate copolymerization equation (NLLSQ-P) methods, which used Python’s NumPy, SciPy, and SymPy libraries to generate code and did numerical computations, bringing greater accuracy of monomer reactivity ratios. The monomer reactivity ratios were calculated with Fineman–Ross, Kelen–Tüdös, YBR, NLLSQ-T, and NLLSQ-P methods and found to be r
AA = 10.888, r′
AA = 1.131, r
TPEG = 0.012, and r′
TPEG = 0.042 for AA-TPEG copolymers. Moreover, this study also explored specific copolymerization behavior of similar structure of copolymers with steric hindrance under penultimate copolymerization equation, such as dependence of the mole fractions in the copolymer on the mole fractions of unreacted monomers in solution, variation of copolymer compositions with conversion and sequence length distribution. The fluidity and flow loss of pastes containing PCEs were investigated, and the appropriate PCEs dosages resulted in a better workability of cement pastes.
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INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2017
·
IF 2.843
Xiaoda Wang,Qinglian Wang,Changshen Ye,Xiaolian Dong,Ting Qiu
This paper aims to present the feasibility of conducting the transesterification of propylene glycol ether (PM) with methyl acetate (MeAc) in a reactive distillation (RD) column to improve the reaction conversion. The essential thermodynamic and reaction kinetic data of the reaction system were measured for the feasibility study. There is only one azeotrope, MeAc–MeOH, in the reaction system, and the NRTL model could describe well the thermodynamic behavior of this system. The transesterification of PM with MeAc is an endothermic reaction with activation energy E = 55.704 kJ·mol–1. The feasibility was analyzed by residue curve maps (RCM), showing that full conversion of PM could be realized by RD with a mole ratio of MeAc–PM larger than 2.882. The intensification effect was experimentally verified in a batch RD column. Finally, some important parameters are given through the conceptual design to develop a continuous RD column for the transesterification of PM with MeAc.
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ACS Omega
·
2017
·
IF 0
Yujuan Chen,Qian Yang,Panpan Xu,Li Sun,Dong Sun,Kelei Zhuo
Acidophilic highly-photoluminescent ionic liquid (IL)-modified carbon dots (CDs) were fabricated directly from polyethylene glycol-2000 (PEG2000N) by a simple one-step hydrothermal method in a system containing an IL (1-butyl-3-methylimidazolium bromide [C4mim]Br) and hydrochloric acid (HCl). In this process, PEG2000N works as the carbon source, [C4mim]Br as the modifier, and HCl as the accelerator. CDs with low photoluminescence (PL) intensity and quantum yields (QYs) were generated in the system without H+, but CDs with high PL intensity and QYs could be prepared after H+ was introduced. Moreover, with the increase of H+ concentration, the QYs of the prepared CDs increase subsequently, and the highest QY reaches up to 43%. The formation mechanism was explored, and the results showed that H+ changes the surface groups of the CDs generated without H+ into those that exist on the CDs generated with H+, which further improves the PL performance of the CDs. Different from most CDs reported in the literature, the as-prepared CDs can still exhibit high PL intensity even under strong acidic condition.
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INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
·
2017
·
IF 3.458
Yufeng Guo,Tongtong Zhang,Dongrui Zhang,Qi Wang
In this paper, the thermal conductivity and electrical conductivity of SiO 2 nanofluids using mixture of ethylene glycol (EG) and water (H 2 O) as the base fluid are investigated. The two-step method was used to prepare SiO 2 -EG/H 2 O nanofluids with a mass concentration of 0.3%. The variations in thermal conductivity and electrical conductivity as functions of EG concentration (0–100%, v/v) and temperature (25–45 °C) are present. Experimental results showed that the thermal conductivity and electrical conductivity of SiO 2 -EG/H 2 O nanofluids both decreased as the EG content percentage increases in the EG/H 2 O mixture. At a specific EG content percentage, thermal conductivity and electrical conductivity both increased with the increase in temperature. To better evaluate the enhancement performance of SiO 2 -EG/H 2 O nanofluids, the relative electrical conductivity was introduced and studied explicitly. The mechanism of electrical conductivity enhancement in SiO 2 -EG/H 2 O nanofluids was analyzed in detail. Meanwhile, the ratio of thermal conductivity and electrical conductivity was also discussed.
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MICROCHIMICA ACTA
·
2017
·Vol. 184
·期 3
·915-919
·
IF 4.58
Yu Haili,Long Dengying
The authors report on a simple colorimetric method for the determination of ethylene glycol (EG) in aqueous solution. It is based on the finding that EG prevents the aggregation of silver nanoparticles (AgNPs) on freezing-thawing. In the absence of EG, AgNPs aggregate after freeze-thawing because their surface were disrupted by ice crystals. This causes the solution to become colorless. However, in the presence of EG, ice crystals are not formed, and aggregation and decoloration do not occur. Under optimized conditions, the photometric assay, best performed at a wavelength of 395 nm, works in the 10 to 400 mM EG concentration range, and the detection limit is 3 mM (at a signal-to-noise ratio of 3). Concentrations down to 100 mM can be even detected visually.
A visual and colorimetric method for detection of ethylene glycol (EG) was developed based on freeze-thawing induced aggregation of silver nanoparticles.
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Polymer Chemistry
·
2017
·Vol. 8
·期 45
·6964-6971
·
IF 5.375
Yanxin Qi,Bin Li,Yupeng Wang,Yubin Huang
Given the increasing prosperity of multifunctional poly(ethylene glycol) (mf-PEG), an amphiphilic triblock copolymer, poly(ethylene glycol)-block-poly(ε-caprolactone)-block-poly(allyl glycidyl ether) (mPEG-PCL-PAGE), was synthesized by a combination of living ring-opening polymerization (ROP) and click chemistry. A post-modification of the allyl groups can be achieved via a radical mediated thiol–ene reaction to prepare copolymers bearing side-chain carboxylic or amino groups [mPEG-PCL-PAGE(R)]. The chemical structures and compositions of these polymers were systematically characterized using Fourier transform infrared spectroscopy (FT-IR), proton nuclear magnetic resonance spectroscopy (1H NMR) and gel permeation chromatography (GPC). The copolymers could readily assemble into micelles in aqueous solution as confirmed by fluorescence spectroscopy, dynamic light scattering (DLS), transmission electron microscopy (TEM) and zeta potential measurements. MTT and hemocompatibility assays indicated that the micelles showed no associated cytotoxicity and could be potentially used for nanomedicine. Intriguingly, the specific sequence of [mPEG-PCL-PAGE(R)] showed pH-induced morphology transformation, while the corresponding polymer with a middle PAGE segment [mPEG-PAGE(R)-PCL] did not, which, we propose, was attributed to the tunable hydrophilicity and distinctive folding of the molecular chain at varied pH values. This finding offers a route to regulate the self-assembly behaviors in polymer systems by controlling the block sequence.
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ELECTROANALYSIS
·
2016
·Vol. 29
·期 3
·682-685
·
IF 2.471
Wei Hong,Changshuai Shang,Jin Wang,Erkang Wang
In this research, we reported an effective approach to prepare low cost and efficient electrocatalyst for the glycol electrooxidation. The synthetic process involves the replacement reactions between CuCl 2 /H 2 PdCl 4 and Ni nanospheres template. Through controlling the precursor ratio, the Pd/Cu/Ni ratio of the final trimetallic products can be tuned. The prepared electrocatalysts present a monodispersed nanospheres structure with a hollow cavity. The prepared Pd 41 Cu 27 Ni 9 shows the best catalytic activity (0.021 A cm −2 at 0.9 V vs. RHE) for glycol electrooxidation, which is much higher than that of the commercial Pd/C (0.0014 A cm −2 at 0.9 V vs. RHE).
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ACS Applied Materials & Interfaces
·
2024
·
IF 8.3
Qiao Qiao,Xiao-Song Xiong,Xiao-Qin Ni,Li-Jun Fu,Xiao-Ming Ren,Teunis van Ree,Yu-Ping Wu
Solid-state electrolytes (SSEs) have garnered significant attention as critical materials for enabling safer, energy-dense, and reversible electrochemical energy storage in batteries. Among the various types of solid electrolytes developed, composite polymer electrolytes (CPEs) have stood out as some of the most promising candidates due to their well-rounded performance. In this study, we choose polyethylene glycol (PEG) as the covalent grafting intercalant and lithium perchlorate as carrier source to prepare a fast lithium ion conductor, K-PEG-Li doped with clay-based active filler as a CPE. The CPE exhibits excellent lithium conduction (4.36 × 10–3 S cm–1 at 25 °C and 3.32 × 10–2 S cm–1 at 115 °C), great mechanical performance with good tensile strength (6.07 MPa) and toughness (strain 313%), and convincing flame-retardancy. These outstanding conducting and mechanical functionalities indicate that such a clay-based active filler doped composite polymer electrolyte will find promising application in solid-state lithium batteries.
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RSC Advances
·
2017
·Vol. 7
·期 84
·53346-53354
·
IF 3.108
Zhuang Xu,Wenjing Lou,Xinhu Wu,Xiaobo Wang,Junying Hao
MoS2–polydopamine–methoxypolyethyleneglycol amine (MoS2–PDA–MGA) was synthesized through the combination of mussel-inspired chemistry and the Michael addition reaction. The modification of MoS2 via PDA and MGA enhanced its dispersion stability in oil. The tribological properties of MoS2–PDA–MGA for use as additives in polyalkylene glycol (PAG) base oil were investigated using an oscillating reciprocating tribometer at elevated temperatures. The results indicated that the addition of 0.7 wt% MoS2–PDA–MGA in PAG resulted in excellent friction-reducing and anti-wear (AW) performances compared with PAG base oil. The tribological results of MoS2–PDA–MGA and MoS2 dispersed in PAG base oil after settling for 7 days indicate that MoS2–PDA–MGA, with its good dispersion stability, has stable friction-reducing and AW properties. XPS analysis suggested that a protective boundary film formed on the wear surfaces during the friction and wearing process, which was believed to be responsible for the excellent tribological performance of MoS2–PDA–MGA dispersed in PAG at elevated temperature.
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INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
·
2024
·
IF 7.7
Mengting Zhang,Shujun Liu,Xianqiang Gao,Xiaokang Jiang,Enze Zhang,Hai Fan,Shuhua Zhu
Cellulose acetate film, as a biodegradable and biomass-derived material, has great potential applications in food packaging. However, the poor mechanical and antibacterial properties limit its applications. Herein, a highly flexible carbon nitride-polyethylene glycol-cellulose acetate (CN-PEG-CA) film was successfully prepared by combining graphitic carbon nitride (g-C 3 N 4 ) photocatalyst with cellulose acetate (CA). The g-C 3 N 4 enables the film with antibacterial activity, as a green photocatalyst. PEG softens the rigid polymer CA and crosslinks CA, PEG, and g-C 3 N 4 together by hydrogen bonding, as a flexible crosslinker. X-ray diffractometer (XRD), scanning electron microscope (SEM), and Fourier transform infrared spectrum (FT-IR) characterizations confirmed the successful preparation of the CN-PEG-CA film. The mechanical property tests demonstrated that adding PEG increased the elongation at break of the film by about 4 times. The composite film had high antibacterial activity, and the bactericidal rates on Escherichia coli and Staphylococcus aureus were 99.98 % and 99.89 %, respectively. It effectively extended the shelf life of strawberries to 96 h and effectively maintained the quality of strawberries during storage. After 96 h, the weight loss rate of strawberries packaged with 15 % CN-PEG-CA film was 21.83 %, vitamin C content was 45.47 %, titratable acidity content was 0.89 %, and color, hardness and total soluble solids were well maintained. And biocompatibility test results showed that the film was safe and nontoxic. From the ecological and economic point of view, the highly flexible and biodegradable films with efficient photocatalytic antibacterial activity synthesized in this paper have great potential in the field of food packaging.
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Journal of Environmental Chemical Engineering
·
2024
·
IF 7.4
Hao Dong,Bo Wang,Xiandong Hao,Jinyu Wang,Zhiyong Xu,Wenbo Zhao
Seeking top-performing absorbents with excellent structural stability and renewability to realize efficient removal of H 2 S from natural gas is of great importance. Here, the H 2 S absorption thermodynamic and kinetic properties by a non-aqueous liquid binary blend of monoethanolamine (MEA) and ethylene glycol (EG) was systematically studied. The addition of solvent EG not only improves the thermal stability but also reduces the viscosity of the system especially after H 2 S absorption. The absorption mechanism was revealed by the combination of experimental characterization and Density Functional Theory (DFT) calculations, which show that the absorption process is a proton transfer reaction. In addition, a quasi-primary kinetic model was used to describe the absorption kinetic behavior, with rate constants increasing with temperature and pressure. Reaction equilibrium thermodynamic model (RETM) fitting thermodynamic results showed that the enthalpy (ΔH) and entropy (ΔS) of the interaction of the absorbent with H 2 S was −40.72 kJ/mol and −114.71 J/mol/K, respectively. Most importantly, the optimum absorption temperature was calculated to be 287.80 K and the optimum desorption temperature was 386.62 K. Moreover, the desulphurization rate was verified to increase with decreasing temperature and increasing H 2 S partial pressure. Five cycles of absorption-desorption experiments were conducted at 313.15 K for absorption and 373.15 K for desorption in order to verify the good reuse properties of the absorbent. Considering the excellent thermal stability, low viscosity after H 2 S absorption, acceptable absorption capacity as well as good reversibility, it is believed that the MEA/EG blend has a significant potential in the field of desulfurization.
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JOURNAL OF CHEMICAL AND ENGINEERING DATA
·
2017
·
IF 2.323
Qingsong Li,Midong Shi,Liping Wang,Gaoyin He,Fan Gan
The liquid–liquid equilibrium (LLE) experiments for n-butanol + n-hexane + ethylene glycol were carried out and LLE data were measured at 298.15, 303.15, 308.15, 313.15, and 323.15 K under atmospheric pressure. The analysis results of the effects of n-butanol content and temperature on extraction showed that high n-butanol content was not favorable for extraction, and temperature had little effect on extraction. Moreover, the NRTL and UNIQUAC models were applied to correlate the LLE data, and the correlated data indicated that the UNIQUAC model showed a better correlation performance.
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