FLUID PHASE EQUILIBRIA
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2015
·
IF 2.2
Tianxiang Zhao,Feng Sha,Jianbai Xiao,Qiang Xu,Xiaohong Xie,Jianbin Zhang,Xionghui Wei
Isothermal gas–liquid equilibrium (GLE) data were measured at 298.15 K and 122.66 kPa for dilute SO 2 in the binary system ethylene glycol (EG) + dimethyl sulfoxide (DMSO), in which SO 2 partial pressures were calculated in range of (0–130) Pa. The solubility of dilute SO 2 in the binary system gradually increased with the increasing DMSO concentration in the whole composition . Based on the GLE data, Henry’s law constants ( HLC ) of dilute SO 2 in the binary system EG (1) + DMSO (2) were obtained. The regeneration experiments showed that the 97.6% SO 2 could be separated from the dissolving SO 2 solution at 80 °C and bubbling N 2 within 30 min; meanwhile, SO 2 desorption ran smoothly and solubility of SO 2 no significant dropped after five-successive absorption–desorption cycles. Furthermore, to obtain important reaction mechanism, the intermolecular interaction among SO 2 , EG, and DMSO were investigated by UV–vis, FTIR, and 1 H NMR spectroscopic techniques. Spectral results showed that the interaction among EG, DMSO, and SO 2 were resulted from both the O → S charge-transfer interaction and intermolecular hydrogen bonding .
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高影响因子
Macromolecular Reaction Engineering
·
2014
·Vol. 9
·期 2
·90-99
·
IF 1.543
Xiaohui Li,Wen-Jun Wang,Bo-Geng Li,Shiping Zhu
This work reported branching studies in reversible addition-fragmentation chain transfer (RAFT) miniemulsion copolymerization of styrene and triethylene glycol dimethacrylate (TEGDMA), and control of branching density distribution using a model-based computer-programed monomer feeding strategy. Highly branched polystyrenes (PS) were produced with small amount of TEGDMA. The branching density experienced drifting in a batch operation. A semi-batch kinetic model by combining the kinetic model for RAFT miniemulsion copolymerization with a semi-batch reactor model was used to design the monomer feeding rate profiles for targeted branching density distributions. A series of hyperbranched PSs with the designed branching density distributions were synthesized.
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高影响因子
Polymer Chemistry
·
2014
·Vol. 5
·期 10
·3346-3351
·
IF 5.368
Shusheng Zhang,Wenxin Fu,Zhibo Li
A poly(ethylene glycol)-b-poly(γ-(2-methoxyethoxy)esteryl-L-glutamate) (PEG-b-poly-L-EG2Glu) diblock was prepared by the ring-opening polymerization (ROP) of L-EG2Glu N-carboxyanhydride (NCA) using PEG–NH2 as the macroinitiator. When the average degree of polymerization (DP) for poly-L-EG2Glu was below 40, the PEG-b-poly-L-EG2Glu diblock could spontaneously form hydrogels in water. For the different diblocks, a thermally-induced increase in mechanical strength was observed for the PEG-b-poly-L-EG2Glu diblock between 20–45 °C. Transmission electron microscopy (TEM) and atomic force microscopy (AFM) revealed that continuous networks of nanoribbons were formed in these hydrogel samples. Circular dichroism (CD) and Fourier transform infrared spectroscopy (FTIR) characterization suggested that the formation of sufficient β-sheet content accounted for the nanoribbon assemblies and hydrogel networks. The minimal gelation concentration and gel mechanical properties were found to strongly depend on the composition of the PEG-b-poly-L-EG2Glu diblocks.
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高影响因子
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
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2015
·
IF 3.313
Yan Yang,Wei Wang,Fengxia Wang,Yanqin Liu,Dan Chai,Ziqiang Lei
In this study, a novel Pd-(NiFe) x -(NiFeO) y /C catalyst is fabricated by supporting Pd on partially oxidized nickel–iron alloy. Because of the promotion effect between nickel–iron alloy and nickel–iron oxide towards Pd, the catalyst exhibits excellent electrocatalytic performance for ethylene glycol oxidation . Specifically, it has much larger electrochemically active surface area, better electrocatalytic activity and durability compared to Pd/C counterpart. After all, this strategy is well suited to synthesize other metal alloys and oxides synergistically promoting Pd electrocatalysts for direct ethylene glycol fuel cells.
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高影响因子
SOLAR ENERGY MATERIALS AND SOLAR CELLS
·
2015
·
IF 5.337
Zhao Li,Wei He,Jianjun Xu,Mengjin Jiang
In this study, an in situ grafting/crosslinking method was employed to prepare form stable thermal regulating fibers (TRFs). The fibers were made from polyvinyl alcohol (PVA, as fiber polymer), polyethylene glycol (PEG, as phase change material) and butane tetracarboxylic acid (BTCA, as crosslinking agent) and spun by dry spinning. The addition amount of BTCA and thermal treatment temperature for preparation were optimized by studying the reaction kinetics of PVA/BTCA and PEG/BTCA composite systems . The structures and properties of PEG/PVA/BTCA composite fibers were characterized by differential scanning calorimeter (DSC), two-dimensional wide angle X-ray diffraction (WAXD) and scanning electron microscope (SEM). Results show that small amounts of BTCA can form adequate chemical bonds to fix PEG in the PEG/PVA/BTCA composite at proper temperatures in the thermal treatment. In composite fibers, the crystallization of PVA promotes the phase separation between PVA and PEG, and the crosslinkages confine the crystallization of PEG. In the as-spun fiber, the crystallization of PEG occurred along the normal direction of the fiber axis . During the stretching, the original orientation of PEG crystals in fibers was destroyed and then new crystalline orientation formed along the fiber axis. The cross-sections of the composite fibers are almost round; after being extracted, the fibers crosslinked by BTCA are denser and have fewer defects than un-crosslinked PEG/PVA fiber, which demonstrated that the PEG can be fixed steadily in PVA fiber matrix by the in situ grafting/crosslinking method.
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高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
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2015
·
IF 2.587
Bin Xiao,Mingyuan Zheng,Jifeng Pang,Yu Jiang,Hua Wang,Ruiyan Sun,Aiqin Wang,Xiaodong Wang,Tao Zhang
Using biomass-derived ethylene glycol (bio-EG) to synthesize poly(ethylene terephthalate) (PET) is of notable significance for alleviating the dependence on fossil energy resources. Bio-EG readily contains a small amount of miscellaneous diols, which derive from the side reactions in the catalytic conversion of biomass. To disclose the effects of miscellaneous diols on the synthesis and properties of PET, EG feedstock containing four 1,2-diols, i.e., 1,2-propylene glycol, 1,2-butanediol, 1,2-pentanediol, and 1,2-hexanediol at 0–10% concentrations was used for the synthesis of PET. The molecular weights, intrinsic viscosities, and thermal and mechanical properties of obtained PET materials were measured. It was found that when the overall content of miscellaneous diols in EG was lower than 5%, the molecular weights and thermal properties of the prepared PET materials were very similar to that of PET synthesized from pure EG. The miscellaneous diols were less likely to be incorporated into PET resin because of the steric hindrance of the alkyl group in diols to the esterification and polycondensation reactions. Instead, they preferred to undergo dehydration reactions to form low-boiling-point aldehydes and hemiacetals, which could be removed from the reaction system during the reactions. Three bio-EG samples at purities of 99.9, 98.5, and 95.8 wt % were used for the bio-PET synthesis. Transparent and colorless bio-PET samples were obtained, demonstrating that the presence of miscellaneous diols does not have negative effects on the color quality of PET. The physical properties of bio-PET prepared with bio-EG at a purity of higher than 98 wt % were nearly the same as those of PET derived from pure EG. At a lower bio-EG purity of 95.8 wt %, the tensile strength of the obtained bio-PET sample was slightly decreased. The comprehensive results of property characterization show that bio-PET materials prepared with bio-EG at purity higher than 95 wt % could be used as widely as the conventional petro-PET resin without notable deterioration in their performance.
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JOURNAL OF SUPERCRITICAL FLUIDS
·
2014
·
IF 2.571
Qin-Qin Xu,Yu-Ling Ma,Gang-Xu,Jian-Zhong Yin,Ai-Qin Wang,Jin-Ji Gao
Well-defined Ag nanowires were obtained in SBA-15 at a short deposition time of 5 min in supercritical CO 2 when adding a small amount of ethylene glycol as the co-solvent. Ethylene glycol played a key role in dictating the nanowire morphology. Through detailed investigation of the whole deposition process, including the dissolution of precursor assisted by the co-solvent, the diffusion properties of the precursor into the nano-scale channels of the substrate, and the interaction between the precursor and the substrate, we found that a small amount of precursors were reduced into Ag 0 by ethylene glycol at the initial stage of the deposition. The resultant Ag 0 then acted as nuclei leading to a non-equilibrium sorption of the precursor. The rapid adsorption of the precursor onto the substrate resulted in a high loading of Ag in a short deposition time and the formation of nanowire morphology. Furthermore, this method was successfully extended to other porous substrates such as γ-Al 2 O 3 , SiO 2 and KIT-6, demonstrating its great potentials in the synthesis of nanocomposites.
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Analytical Methods
·
2017
·Vol. 9
·期 31
·4533-4538
·
IF 1.9
Fei Qu,Fangfang Xue,Jing Liu,Jinmao You
In this paper, a simple and green preparative strategy for synthesizing carbon nanodots (CNDs) is developed by a one-pot hydrothermal method, using ascorbic acid (AA) as the carbon source and polyethylene glycol (PEG) with a molecular weight of 1500 as the surface modification agent. Through changing the amount ratio of PEG-1500 to AA in the synthesis, we can obtain PEG-CNDs with different functions. For example, due to the thermosensitivity of PEG-1500, the as-prepared PEG1-CNDs exhibit unique temperature sensitivity when the mass ratio of PEG-1500 to AA is 24 : 1. A reversible change of PEG1-CNDs from the solid state to transparent solution with increasing temperature can be repeated several times. The optical transmittance signal of PEG1-CNDs linearly responds to temperature in the range of 20–65 °C. Besides, while the amount ratio of PEG-1500 to AA is 12 : 1, the obtained PEG2-CNDs lose thermal sensitivity and form a stable and fluorescent solution at room temperature. The emission of PEG2-CNDs can be quenched by Fe3+, while with the addition of paracetamol (PAR), the fluorescence is recovered because of forming chelates between Fe3+ and PAR. Under the optimized conditions, the linear range of PAR obtained is 0.03–30 μM with a detection limit of 13 nM. Finally, the proposed method is successfully applied to detect PAR in human serum and urine samples with satisfactory recoveries.
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JOURNAL OF BIOMATERIALS SCIENCE-POLYMER EDITION
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2017
·
IF 1.9
Peizong Deng,Fangfang Teng,Feilong Zhou,Zhimei Song,Ning Meng,Runliang Feng
Ketoconazole is a broad spectrum imidazole antifungal drug. For the treatment of superficial fungal infections with ketoconazole, it needs to be permeated to deep skin layers. In order to develop topical formulation of ketoconazole for improving its skin deposition and water-solubility, ketoconazole-loaded methoxy poly (ethylene glycol)-b-poly (δ-valerolactone) micelles were developed through thin-film hydration method. Particle size, drug loading capacity, infrared spectrum and X-ray diffraction of drug-loaded micelles were characterized. The optimal drug formulation was selected for skin delivery and deposition investigation performed by use of mice skin, and its in vitro release and antifungal activity were also investigated. Penetration and distribution in the skin were also visualized using fluorescein-loaded micelles and fluorescence microscopy. The drug-loaded micelles were obtained with encapsulation efficiency of 86.39% and particle diameter of about 12 nm. The micelles made ketoconazole aqueous solubility increase to 86-fold higher than crude one. Ketoconazole-loaded micelles showed no skin permeation of ketoconazole, obviously enhance skin deposition and demonstrated similar antifungal activity as compared with marketed ketoconazole cream. Fluorescein-loaded micelles displayed higher skin deposition than fluorescein water solution. These results demonstrate that the MPEG-PVL micelle is a potential delivery system for ketoconazole in the field of skin delivery.
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PubMed
高影响因子
Polymer Chemistry
·
2016
·Vol. 7
·期 10
·1913-1921
·
IF 5.687
Yefei Tian,Shanshan Bian,Wuli Yang
Stimuli-responsive nanomaterials have promising prospects of application in controlled intracellular drug delivery. In this paper, we fabricated thermo- and redox-responsive biodegradable nanogels by precipitation copolymerization of 2-(2-methoxyethoxy)ethyl methacrylate, oligo(ethylene glycol)methacrylate, and a disulfide-containing crosslinker, N,N′-bis(acryloyl)cystamine. The poly(oligo(ethylene glycol)methacrylate) (POEGMA)-based nanogels exhibit a sharp volume collapse at their volume phase transition temperatures (VPTT), which are tunable in a wide temperature range. By incorporating disulfide bonds into polymer networks, the nanogels are endowed with an excellent redox-labile property that they can degrade efficiently into short polymer chains (Mw < 2000) in the presence of a reducing agent (glutathione or dithiothreitol). The anticancer drug (doxorubicin, DOX) loaded nanogels display a well-controlled release behavior, that is, low leakage of DOX under physiological conditions (only 8.1% in 48 h) and rapid and sufficient release of DOX in a reducing environment (92.2% in 48 h). Cell viability assays reveal that the blank nanogels have negligible cytotoxicity against normal cells (HEK-293T cells), while DOX-loaded nanogels present a significant inhibitive effect on tumor cells (HeLa cells).
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POLYMERS FOR ADVANCED TECHNOLOGIES
·
2016
·Vol. 27
·期 8
·1029-1037
·
IF 1.823
Peng Li,Guisheng Yang
Poly(trimethylene terephthalate)/poly(propylene glycol) (PTT/PPG) segmented random copolymers were synthesized by melt copolycondensation. The weight fraction of PPG blocks was ranged from 12.1 to 33.4 wt%, which was confirmed by 1 H NMR spectroscopy. The result of wide-angle X-ray diffractometer indicated that all copolymers had the same crystal structure of PTT homopolymer at room temperature. At a determined crystallization temperature, ring-banded spherulites could be observed in all copolymers samples, and the band spacing increased with the increase of PPG content. Morphologies of copolymers after nonisothermal crystallization process were strongly depended on the cooling rate. Well-defined ring-banded spherulites can be observed only at moderate cooling (20°C/min), while it was really hard to be observed at too low (2.5°C/min) or too high (by air-quenching) cooling rate. Moreover, the size of spherulites decreased with the increase of cooling rate. Finally, different nonisothermal crystallization kinetics were adopt to analyze this copolymer system, and only the Mo method was suitable to describe this copolymer system. Copyright © 2016 John Wiley & Sons, Ltd.
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COMPOSITES COMMUNICATIONS
·
2017
·
IF 0
Yiqi Sun,Shuai Sun,Lei Chen,Lina Liu,Pingan Song,Wei Li,Youming Yu,Lu Fengzhu,Jun Qian,Hao Wang
Although the flammability of biodegradable poly(lactic acid) (PLA) has been effectively addressed so far, the resultant flame retardant PLA still displays a high brittleness , extremely restricting its wide applications in electrical, automobile and aerospace fields. In this work, we have demonstrated the fabrication of flame retardant and tough PLA composites by combining ammonia polyphosphate (APP) and poly(ethylene glycol) (PEG) with a molecular weight of 20,000 via the melt-blending strategy. The results show that the peak heat release rate of PLA can reduce by 14% in cone tests and a V-0 rating is achieved in vertical burning tests by adding 7 wt% of APP and 14 wt% PEG. Moreover, such PLA composite shows a high strain at break of 280% and impact strength of 14.9 kJ/m 2 , respectively increasing by thirty-eight-fold and two-fold relative to the PLA bulk. The results strongly indicate that flammability and brittleness of the PLA are strikingly reduced. This work provides an integrated strategy for creating advanced green polymer composites with exceptional flame resistance and toughness.
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