Biomass-to-ethylene glycol is an effective means to achieve high-value utilisation of cellulose but is hindered by low conversion efficiency and poor catalyst activity and stability.Glucose and cellobiose are derivati...Biomass-to-ethylene glycol is an effective means to achieve high-value utilisation of cellulose but is hindered by low conversion efficiency and poor catalyst activity and stability.Glucose and cellobiose are derivatives of cellulose conversion to ethylene glycol,and it is found that studying the reaction process of both can help to understand the reaction mechanism of cellulose.It is desirable to develop a reusable,highly active catalyst to convert cellulose into ethylene glycol.This ideal catalyst might have one or more active sites described the conversion steps above.Here,we discuss the catalyst development of celluloseto-ethylene glycol,including tungsten,tin,lanthanide,and other transition metal catalysts,and special attention is given to the reaction mechanism and kinetics for preparing ethylene glycol from cellulose,and the economic advantages of biomass-to-ethylene glycol are briefly introduced.The insights given in this review will facilitate further development of efficient catalysts,for addressing the global energy crisis and climate change related to the use of fossil fuels.展开更多
Thermodynamic and kinetic aspects of Sn nucleation and growth processes onto a glassy carbon electrode from SnCl2·2H2O dissolved in ethylene glycol solutions were studied.Typical reduction and oxidation peaks obs...Thermodynamic and kinetic aspects of Sn nucleation and growth processes onto a glassy carbon electrode from SnCl2·2H2O dissolved in ethylene glycol solutions were studied.Typical reduction and oxidation peaks observed in voltammograms have demonstrated the capability of ethylene glycol solutions to electrodeposit Sn.The temperature-dependence of diffusion coefficient values derived from potentiodynamic and potentiostatic studies helped to determine and validate estimations of the activation energy for Sn(II)bulk diffusion.Chronoamperometric results have identified that,the suitable model to describe the early stage of Sn electrodeposition could be composed of Sn three-dimensional nucleation and diffusion-controlled growth and water reduction contributions,which was duly validated by theoretical and experimental approaches.From the model,typical kinetic parameters such as the nucleation frequency of Sn(A),number density of Sn nuclei(N_(0)),and diffusion coefficient of Sn(II)ions(D),were determined.The presence of Sn nuclei with excellent quality and their structures were verified using SEM,EDX,and XRD techniques.展开更多
A poly(L-lactide)-b-poly(ethylene glycol)-b-poly(L-lactide)(PLLA-PEG-PLLA)block copolymer has great potential for use as a flexible bioplastic.Highly flexible bioplastics are required for flexible packaging applicatio...A poly(L-lactide)-b-poly(ethylene glycol)-b-poly(L-lactide)(PLLA-PEG-PLLA)block copolymer has great potential for use as a flexible bioplastic.Highly flexible bioplastics are required for flexible packaging applications.In this work,a PEG was incorporated into block copolymer as a plasticizer by solvent casting.PLLA-PEG-PLLA/PEG blends with different blend ratios were prepared,and the plasticizing effect and miscibility of PEG in block copolymer were intensively investigated compared to PLLA/PEG blends.The results indicated that the PEG was an effective plasticizer for the block copolymer.The blending of PEG decreased glass-transition temperature and accelerated the crystallization of both the PLLA and PLLA-PEG-PLLA matrices.The PEG was completely miscible when blended with block copolymer and it improved thermal stability of the block copolymer matrix but not of the PLLA matrix.Film extensibility of PLLA-PEG-PLLA/PEG blends steadily increased as the PEG ratio increased.These non-toxic and highly flexible PLLA-PEG-PLLA/PEG bioplastics are promising candidates for several applications such as biomedical devices,tissue scaffolds and packaging materials.展开更多
Thermo-responsive random copolymers,poly(2-(2-methoxyethoxy)ethoxyethyl methacrylate-co-(ethylene glycol)methyl ether methacrylate)(P(EO_(2)-co-EO_(4/5)))and poly(2-(2-methoxyethoxy)ethoxyethyl methacrylate-co-ethylen...Thermo-responsive random copolymers,poly(2-(2-methoxyethoxy)ethoxyethyl methacrylate-co-(ethylene glycol)methyl ether methacrylate)(P(EO_(2)-co-EO_(4/5)))and poly(2-(2-methoxyethoxy)ethoxyethyl methacrylate-co-ethylene glycol methacrylate(P(EO2-co-EG4/5))are synthesized via atom transfer radical polymerization(ATRP).The successful synthesis and the narrow polydispersity index(PDI)of two copolymers are indicated by 1H nuclear magnetic resonance(1H-NMR)and gel permeation chromatography(GPC)analyses.The transition behaviors of polymers in the aqueous solution are demonstrated by changes in turbidity and particle sizes.The transition behavior of P(EO2-co-EG4/5)is found to be milder than that of P(EO2-co-EO4/5).Moreover,the presence of hydrogen bonds without thermo-responsive properties established by hydroxyl groups in the end-side chain of P(EO_(2)-co-EG_(4/5))hinders the dehydration at the transition temperature(TT).Attenuated total reflection Fourier transform infrared spectrometry(ATR-FTIR)analysis along with contact angle measurements reveals that both P(EO_(2)-co-EO_(4/5))and P(EO_(2)-co-EG_(4/5))films undergo phase transitions from hydrophilicity to hydrophobicity above TT.By examining the swelling and collapse behaviors of the polymer films during phase transitions,it can be concluded that the end hydroxyl groups may establish hydrogen bonds with neighboring ether groups within the films,which remain intact throughout the phase transition process due to their strong bonding interactions.This leads to an increase in steric hindrance within swollen films thereby impeding dehydration processes and inducing hysteresis during phase transitions.展开更多
To overcome the shortcomings of traditional degumming process,an efficient and environmentally friendly ethylene glycol(EG) degumming process was adopted to degum hemp fibers.The surface morphology,chemical compositio...To overcome the shortcomings of traditional degumming process,an efficient and environmentally friendly ethylene glycol(EG) degumming process was adopted to degum hemp fibers.The surface morphology,chemical composition,chemical structures,and mechanical properties of the fiber samples were analyzed to explore the mechanism of the degumming process.It was found that the EG degumming process could be divided into the main degumming stage(heating) and the supplementary degumming stage(insulation).The removal rates of hemicellulose and lignin in the main degumming stage were 70.56% and 60.17%,respectively.In the supplementary degumming stage,9.95% hemicellulose and 25.39% lignin were removed.It is confirmed that EG can separate hemp fibers effectively with less damage,which holds great potential for the biomass fiber separation technology.展开更多
This work aims to analyze the flow of electrically conducting MWCNTs-nanofluid over a stretching cylinder with the aggregation and non-aggregation effects of nanoparticles. The working fluid comprised a combination of...This work aims to analyze the flow of electrically conducting MWCNTs-nanofluid over a stretching cylinder with the aggregation and non-aggregation effects of nanoparticles. The working fluid comprised a combination of water and ethylene glycol, with volumetric proportions of (50:50) considered. Convective boundary constraints and modified Fourier law are implemented in heat transmission assessment. The mathematical flow model is formulated in the form of PDEs and is transformed into ODEs via similarity transformation. Numerical outcomes will be obtained with the use of the bvp4c technique and will be displayed with the help of graphs and tables. The results show that the surface drag coefficient is enhanced in the case of aggregation of nanoparticles whereas heat transfer rate is enhanced in the non-aggregation effect of nanoparticles. Furthermore, the temperature distribution enhances the increasing values of particle volume fraction in the case of aggregation effects of nanoparticles whereas temperature distribution lowers in the case of non-aggregation effect of nanoparticles. .展开更多
Fouling resistance of ultrafiltration(UF) membranes is critical for their long-term usages in terms of stable performance, so convenient approaches to prepare fouling-resistant membranes are always anticipated. Herein...Fouling resistance of ultrafiltration(UF) membranes is critical for their long-term usages in terms of stable performance, so convenient approaches to prepare fouling-resistant membranes are always anticipated. Herein, we demonstrate the facile fabrication of antifouling polysulfone-block-poly(ethylene glycol)(PSF-b-PEG, SFEG)composite membranes. SFEG layer was coated onto macroporous supports and cavitated by immerging them in acetone/n-propanol following the mechanism of selective swelling induced pore generation. Thus-produced SFEG membranes possessed high permeance and excellent mechanical strength. Meanwhile, the structures and separation performances of the SFEG layers can be continuously tuned through simply changing swelling durations. More importantly, the hydrophilic PEG chains were spontaneously enriched onto the pore walls through swelling treatment, endowing intrinsic antifouling property to the SFEG membranes. Bovine serum albumin(BSA)/humic acid(HA) fouling tests proved the prominent fouling resistance of SFEG membranes, and the fouling resistance is expected to be long-standing because of the firm connection between PEG chains and PSF matrix by covalent bonding.展开更多
Hydrogels composed of poly(vinyl alcohol)(PVA) and poly(ethylene glycol)(PEG) were synthesized using glutaraldehyde as crosslinker and investigated for controlled delivery of the common anti-inflammatory drug, ibuprof...Hydrogels composed of poly(vinyl alcohol)(PVA) and poly(ethylene glycol)(PEG) were synthesized using glutaraldehyde as crosslinker and investigated for controlled delivery of the common anti-inflammatory drug, ibuprofen(IBF). To regulate the drug delivery, solid inclusion complexes(ICs) of IBF in β–cyclodextrin(β–CD) were prepared and added to the hydrogels. The ICs were prepared by the microwave irradiation method, which is more environmentally benign. The formation of IC was confirmed by various analytical techniques and the synthesized hydrogels were also characterized. Controlled release of drug was achieved from the hydrogels containing the ICs in comparison to the rapid release from hydrogels containing free IBF.The preliminary kinetic analysis emphasized the crucial role of β–CD in the drug release process that influences the polymer relaxation, thereby leading to prolonged release. The cytotoxicity assay validated the hydrogels as non-toxic in nature and hence can be utilized for controlled delivery of IBF.展开更多
In order to improve the blood compatibility of silk fibroin (SF), poly(ethylene glycol) macromer (PEGM) in different amounts was added to the SF film to incorporate C=C group into the surface of blend films which were...In order to improve the blood compatibility of silk fibroin (SF), poly(ethylene glycol) macromer (PEGM) in different amounts was added to the SF film to incorporate C=C group into the surface of blend films which were then modified by SO2 gas plasma treatment. ATR-FITR and XPS were used to analyze the chemical change which had occurred on the film's surface. When the content of sulfur on the surface of blend films surpasses 1.59%, the antithrombogenicity of plasma treated films increases remarkably due to surface sulfonation. This result implies that SF with blend of PEGM after SO2 plasma treatment have potential use for making blood-contacting biomaterials.展开更多
Poly (L-lactide)-poly(ethylene glycol) multiblock copolymers with predetermined block lengths were synthesized by polycondensation of PLA diols and PEG diacids. These copolymers presented special properties, such as ...Poly (L-lactide)-poly(ethylene glycol) multiblock copolymers with predetermined block lengths were synthesized by polycondensation of PLA diols and PEG diacids. These copolymers presented special properties, such as better miscibility between the two components, low crystallinity and better hydrophilicity, which can be modulated by adjusting the block lengths of the two components.展开更多
High density polyethylene （HDPE）/polyethylene-block-poly（ethylene glycol） （PE-b-PEG） blend porous membranes were prepared via thermally induced phase separation （TIPS） process using diphenyl ether （DPE） as d...High density polyethylene （HDPE）/polyethylene-block-poly（ethylene glycol） （PE-b-PEG） blend porous membranes were prepared via thermally induced phase separation （TIPS） process using diphenyl ether （DPE） as diluent. The phase diagrams of HDPE/PE-b-PEG/DPE systems were determined by optical microscopy and differential scanning calorimetry （DSC）. By varying the content of PE-b-PEG, the effects of PE-b-PEG copolymer on morphology and crystalline structure of membranes were studied by scanning electron microscopy （SEM） and wide angle X-ray diffraction （WAXD）. The chemical compositions of whole membranes and surface layers were characterized by elementary analysis, Fourier transform infrared spectroscopy-attenuated total reflection （FTIR-ATR） and X-ray photoelectron spectroscopy （XPS）. Water contact angle, static protein adsorption and water flux experiments were used to evaluate the hydrophilicity, antifouling and water permeation properties of the membranes. It was found that the addition of PE-b-PEG increased the pore size of the obtained blend membranes. In the investigated range of PE-b-PEG content, the PEG blocks could not aggregate into obviously separated domains in membrane matrix. More importantly, PE-b-PEG could not only be retained stably in the membrane matrix during membrane formation, but also enrich at the membrane surface layer. Such stability and surface enrichment of PE-b-PEG endowed the blend membranes with improved hydrophilicity, protein absorption resistance and water permeation properties, which would be substantially beneficial to HDPE membranes for water treatment application.展开更多
Cassava residue was liquefied by using ethylene glycol(EG), ethylene carbonate, propylene carbonate and polyethylene glycol(molecular weight: 400 g/mol) as the liquefaction reagent respectively at the temperature of 1...Cassava residue was liquefied by using ethylene glycol(EG), ethylene carbonate, propylene carbonate and polyethylene glycol(molecular weight: 400 g/mol) as the liquefaction reagent respectively at the temperature of 130-170 ℃ with sulfuric acid as the catalyst. The influences of liquefaction parameters, such as the type of liquefaction reagents, mass ratio of EG/cassava residue, liquefaction temperature and time on the properties of the products were discussed. The optimum liquefaction conditions were obtained when the mass ratio of EG/cassava residue was 6:1(w/w), the liquefaction temperature was 150 ℃, the liquefaction time was3 h and the mass fraction of concentrated sulfuric acid/EG was 2.5 wt%. The hydroxyl numbers and residue content of the liquefied products at optimal conditions were 1 137 mgKOH/g and 0.43%, respectively. FT-IR spectrum showed that the liquefaction product of cassava residue was polyether polyol and could be used to prepare polyurethane material or alkyd resins.展开更多
The electrodeposition behaviors of nickel on glassy carbon（GC） and carbon steel（CS） electrodes were investigated in the14.3%-85.7%（mole fraction） betaine.HCl ethylene glycol（EG） ionic liquid using cyclic volta...The electrodeposition behaviors of nickel on glassy carbon（GC） and carbon steel（CS） electrodes were investigated in the14.3%-85.7%（mole fraction） betaine.HCl ethylene glycol（EG） ionic liquid using cyclic voltammetry and chronoamperometry.The results indicated that the reduction of Ni（Ⅱ） on CS electrode via a diffusion-controlled quasi-reversible process was much more facile and easier than that occurred on GC electrode,which followed a diffusion-controlled three-dimensional instantaneous nucleation and growth.Scanning electron microscopy was used to observe that the deposit was dense and contained fine crystallites with average size of（80±4） nm.Energy dispersive spectrometer analysis showed that the obtained deposit was metallic nickel.X-ray diffraction spectroscopy indicated that（111） plane was the most preferred crystal orientation.The nickel deposit was luminous and bright,and had good adhesion with the CS substrate.展开更多
The ternary hybrid films consisting of chitosan(CS),polyethylene glycol(PEG)and nano-sized silica which was surface-modified by amino groups(RNSA)were prepared.The structures of the blend membranes were characterized ...The ternary hybrid films consisting of chitosan(CS),polyethylene glycol(PEG)and nano-sized silica which was surface-modified by amino groups(RNSA)were prepared.The structures of the blend membranes were characterized by attenuation total reflection-infrared spectroscopy(ATR-IR),X-ray diffraction(XRD),optical microscopy(OM)and differential scanning calorimetry(DSC).The results showed that the addition of silica affected not only the distribution and crystallinity of PEG on the sample surface,but also the pha...展开更多
Novel Y-shaped block copolymers of poly（ethylene glycol） and poly（N-isopropylacrylamide）, PEG-b-（PNIPAM）2, were successfully synthesized through atom transfer radical polymerization （ATRP）. A difunctional macr...Novel Y-shaped block copolymers of poly（ethylene glycol） and poly（N-isopropylacrylamide）, PEG-b-（PNIPAM）2, were successfully synthesized through atom transfer radical polymerization （ATRP）. A difunctional macroinitiator was prepared by esterification of 2,2-dichloroacetyl chloride with poly（ethylene glycol） monomethyl ether （PEG）. The copolymers were obtained via the ATRP ofN-isopropylacrylamide （NIPAM） at 30℃ with CuCl/Me6TREN as a catalyst system and DMF/H2O （v/v = 3：1） mixture as solvent. The resulting copolymers were characterized by gel permeation chromatography （GPC） and ^1H NMR. These block copolymers show controllable molecular weights and narrow molecular weight distributions （PDI 〈 1.15）. Their phase transition temperatures and the corresponding enthalpy changes in aqueous solution were measured by differential scanning calorimetry （DSC）. As a result, the phase transition temperature of PEG45-b-（PNIPAM55）2 is higher than that of PNIPAM, however, the corresponding enthalpy change is much lower, indicating the significant influence of the macromolecular composition and architecture on the phase transition.展开更多
Porous polyvinylidene fluoride-co-hexafluropropylene(PVDF-HFP)hollow fiber membranes were fabricated through a wet spinning process.In order to improve the membrane structure,composition of the polymer solution was ad...Porous polyvinylidene fluoride-co-hexafluropropylene(PVDF-HFP)hollow fiber membranes were fabricated through a wet spinning process.In order to improve the membrane structure,composition of the polymer solution was adjusted by studying ternary phase diagrams of polymer/solvent/non-solvent.The prepared membranes were used for sweeping gas membrane distillation(SGMD)of 20 wt% ethylene glycol(EG)aqueous solution.The membranes were characterized by different tests such as N2 permeation,overall porosity,critical water entry pressure(CEPw),water contact angle and collapsing pressure.From FESEM examination,addition of 3 wt% glycerol in the PVDF-HFP solution,produced membranes with smaller finger-likes cavities,higher surface porosity and smaller pore sizes.Increasing the polymer concentration up to 21 wt% resulted in a dense spongy structure which could significantly reduce the N2 permeance.The membrane prepared by 3 wt% glycerol and 17 wt% polymer demonstrated an improved structure with mean pore size of 18 nm and a high surface porosity of 872 m^−1.CEPw of 350 kPa and overall porosity of 84% were also obtained for the improved membrane.Collapsing pressure of the membranes relatively improved by increasing the polymer concentration.From the SGMDtest,the developed membrane represented a maximumpermeate flux of 28 kg·m^−2·h^−1 which is almost 19% higher than the flux of plain membrane.During 120 h of a long-termSGMD operation,a gradual flux reduction of 30% was noticed.In addition,EG rejection reduced from 100% to around 99.5% during 120 h of the operation.展开更多
Poly-dl-lactide-poly(ethylene glycol) (PELA) triblock copolymers were synthesized with lanthanum acetate as the initiator. PELA microspheres with entrapped Vibrio Cholera antigen and outer membrane protein (OMP) were ...Poly-dl-lactide-poly(ethylene glycol) (PELA) triblock copolymers were synthesized with lanthanum acetate as the initiator. PELA microspheres with entrapped Vibrio Cholera antigen and outer membrane protein (OMP) were prepared by a double emulsion W/O/W based on solvent extraction methods. The obtained microspheres showed smooth and spherical surface and their size varied between 0.5 and 5.0 mu m, which are suitable for oral targeting delivery system. The distribution tests in rabbits and mice through scanning electronic micrography and fluorescence microscope indicated that microspheres have successfully reached the immunization-related tissues, such as the liver, spleen and intestinal peyer's patches, following oral administration. The PELA microspheres were also evaluated as an efficient antigen delivery system by enhancing a higher protective ratio against live Vibrios Cholera.展开更多
The mechanism of the hydrophobized poly(ethylene glycol)(PEG)/K^(+) system inhibiting shale hydration was studied by laboratory experiment. The inhibition performance was evaluated through cuttings hot-rolling dispers...The mechanism of the hydrophobized poly(ethylene glycol)(PEG)/K^(+) system inhibiting shale hydration was studied by laboratory experiment. The inhibition performance was evaluated through cuttings hot-rolling dispersion, bentonite inhibition and contact angle tests. The inhibition became stronger as contact angle and PEG concentration increased. A modified cuttings hot-rolling dispersion experiment suggested that these molecular systems did not act through the thermally activated mud emulsion(TAME) mechanism. The interaction of the PEG/K^(+) with clay samples was investigated through adsorption studies and by Fourier transform infrared spectroscopy(FT-IR), X-ray diffraction(XRD) and thermogravimetric analysis(TGA). The adsorption isotherms showed that the presence of K^(+) increased the PEG affinity for the clay surface. This inhibition effect was accompanied by a reduction of the bentonite hydration with PEG adsorption, evidenced by FT-IR, TGA and differential thermogravimetric(DTG) curves. XRD patterns were conclusive in showing that the presence of K^(+) ions limited the expansion of the clay interlamellar region to only one PEG layer, and the terminal hydrophobic segments of the PEG chains turned out to be determinant in enhancement of the inhibitory efficiency. The cuttings hot-rolling dispersion was carried out on water-base drilling fluid with PEG/K^(+), which proved the inhibition performance of PEG/K^(+) in oil field drilling.展开更多
Two-dimensional nuclear overhauser enhancement (2D NOESY)measurements show that sodium dodecyl sulfonate SDSN molecules co-aggregate with poly-ethylene glycol PEG in their aqueous solution at a concentration range of ...Two-dimensional nuclear overhauser enhancement (2D NOESY)measurements show that sodium dodecyl sulfonate SDSN molecules co-aggregate with poly-ethylene glycol PEG in their aqueous solution at a concentration range of SDSN between the so-called co-aggregation concentration (cac) and the. Normal critical micellar concentration (cmc). SDSN micelles are formed when the cmc of SDSN is reached with PEG uniformly distributed in the interior.展开更多
Lactide was synthesized using lactic acid and stannous octoate as raw material and catalyst, respectively. Poly(lactic acid)-poly(ethylene glycol) (PLA-PEG) was prepared by lactide and poly (ethylene glycol) (PEG) via...Lactide was synthesized using lactic acid and stannous octoate as raw material and catalyst, respectively. Poly(lactic acid)-poly(ethylene glycol) (PLA-PEG) was prepared by lactide and poly (ethylene glycol) (PEG) via ring-opening polymerization. The most appropriate technological conditions of synthesis of lactide were researched in the paper. The copolymers were measured by Infrared spectroscopy (IR) and <sup>1</sup>H nuclear magnetic resonance (<sup>1</sup>H NMR). The results proved that the lactide and PLA-PEG were synthesized successfully. Hydrophilic performance of the copolymer was measured by a water contact angle tester after prepared into a flat membrane. The water contact angle changed from 81.5? to 71.6?, which proved that the hydrophily of PLA-PEG was better than PLA.展开更多
基金supported by the National Natural Science Foundation of China(51976112,52206264)special Project Fund of“Taishan Scholar”of Shandong Province(tsqn202103066)Natural Science Foundation of Shandong Province(ZR2022ME109)。
文摘Biomass-to-ethylene glycol is an effective means to achieve high-value utilisation of cellulose but is hindered by low conversion efficiency and poor catalyst activity and stability.Glucose and cellobiose are derivatives of cellulose conversion to ethylene glycol,and it is found that studying the reaction process of both can help to understand the reaction mechanism of cellulose.It is desirable to develop a reusable,highly active catalyst to convert cellulose into ethylene glycol.This ideal catalyst might have one or more active sites described the conversion steps above.Here,we discuss the catalyst development of celluloseto-ethylene glycol,including tungsten,tin,lanthanide,and other transition metal catalysts,and special attention is given to the reaction mechanism and kinetics for preparing ethylene glycol from cellulose,and the economic advantages of biomass-to-ethylene glycol are briefly introduced.The insights given in this review will facilitate further development of efficient catalysts,for addressing the global energy crisis and climate change related to the use of fossil fuels.
文摘Thermodynamic and kinetic aspects of Sn nucleation and growth processes onto a glassy carbon electrode from SnCl2·2H2O dissolved in ethylene glycol solutions were studied.Typical reduction and oxidation peaks observed in voltammograms have demonstrated the capability of ethylene glycol solutions to electrodeposit Sn.The temperature-dependence of diffusion coefficient values derived from potentiodynamic and potentiostatic studies helped to determine and validate estimations of the activation energy for Sn(II)bulk diffusion.Chronoamperometric results have identified that,the suitable model to describe the early stage of Sn electrodeposition could be composed of Sn three-dimensional nucleation and diffusion-controlled growth and water reduction contributions,which was duly validated by theoretical and experimental approaches.From the model,typical kinetic parameters such as the nucleation frequency of Sn(A),number density of Sn nuclei(N_(0)),and diffusion coefficient of Sn(II)ions(D),were determined.The presence of Sn nuclei with excellent quality and their structures were verified using SEM,EDX,and XRD techniques.
基金financially supported by Mahasarakham University。
文摘A poly(L-lactide)-b-poly(ethylene glycol)-b-poly(L-lactide)(PLLA-PEG-PLLA)block copolymer has great potential for use as a flexible bioplastic.Highly flexible bioplastics are required for flexible packaging applications.In this work,a PEG was incorporated into block copolymer as a plasticizer by solvent casting.PLLA-PEG-PLLA/PEG blends with different blend ratios were prepared,and the plasticizing effect and miscibility of PEG in block copolymer were intensively investigated compared to PLLA/PEG blends.The results indicated that the PEG was an effective plasticizer for the block copolymer.The blending of PEG decreased glass-transition temperature and accelerated the crystallization of both the PLLA and PLLA-PEG-PLLA matrices.The PEG was completely miscible when blended with block copolymer and it improved thermal stability of the block copolymer matrix but not of the PLLA matrix.Film extensibility of PLLA-PEG-PLLA/PEG blends steadily increased as the PEG ratio increased.These non-toxic and highly flexible PLLA-PEG-PLLA/PEG bioplastics are promising candidates for several applications such as biomedical devices,tissue scaffolds and packaging materials.
基金Fujian External Cooperation project of Natural Science Foundation,China(No.2022I0042)。
文摘Thermo-responsive random copolymers,poly(2-(2-methoxyethoxy)ethoxyethyl methacrylate-co-(ethylene glycol)methyl ether methacrylate)(P(EO_(2)-co-EO_(4/5)))and poly(2-(2-methoxyethoxy)ethoxyethyl methacrylate-co-ethylene glycol methacrylate(P(EO2-co-EG4/5))are synthesized via atom transfer radical polymerization(ATRP).The successful synthesis and the narrow polydispersity index(PDI)of two copolymers are indicated by 1H nuclear magnetic resonance(1H-NMR)and gel permeation chromatography(GPC)analyses.The transition behaviors of polymers in the aqueous solution are demonstrated by changes in turbidity and particle sizes.The transition behavior of P(EO2-co-EG4/5)is found to be milder than that of P(EO2-co-EO4/5).Moreover,the presence of hydrogen bonds without thermo-responsive properties established by hydroxyl groups in the end-side chain of P(EO_(2)-co-EG_(4/5))hinders the dehydration at the transition temperature(TT).Attenuated total reflection Fourier transform infrared spectrometry(ATR-FTIR)analysis along with contact angle measurements reveals that both P(EO_(2)-co-EO_(4/5))and P(EO_(2)-co-EG_(4/5))films undergo phase transitions from hydrophilicity to hydrophobicity above TT.By examining the swelling and collapse behaviors of the polymer films during phase transitions,it can be concluded that the end hydroxyl groups may establish hydrogen bonds with neighboring ether groups within the films,which remain intact throughout the phase transition process due to their strong bonding interactions.This leads to an increase in steric hindrance within swollen films thereby impeding dehydration processes and inducing hysteresis during phase transitions.
基金Fundamental Research Funds for the Central Universities of Ministry of Education of China(No.2232020A-07)。
文摘To overcome the shortcomings of traditional degumming process,an efficient and environmentally friendly ethylene glycol(EG) degumming process was adopted to degum hemp fibers.The surface morphology,chemical composition,chemical structures,and mechanical properties of the fiber samples were analyzed to explore the mechanism of the degumming process.It was found that the EG degumming process could be divided into the main degumming stage(heating) and the supplementary degumming stage(insulation).The removal rates of hemicellulose and lignin in the main degumming stage were 70.56% and 60.17%,respectively.In the supplementary degumming stage,9.95% hemicellulose and 25.39% lignin were removed.It is confirmed that EG can separate hemp fibers effectively with less damage,which holds great potential for the biomass fiber separation technology.
文摘This work aims to analyze the flow of electrically conducting MWCNTs-nanofluid over a stretching cylinder with the aggregation and non-aggregation effects of nanoparticles. The working fluid comprised a combination of water and ethylene glycol, with volumetric proportions of (50:50) considered. Convective boundary constraints and modified Fourier law are implemented in heat transmission assessment. The mathematical flow model is formulated in the form of PDEs and is transformed into ODEs via similarity transformation. Numerical outcomes will be obtained with the use of the bvp4c technique and will be displayed with the help of graphs and tables. The results show that the surface drag coefficient is enhanced in the case of aggregation of nanoparticles whereas heat transfer rate is enhanced in the non-aggregation effect of nanoparticles. Furthermore, the temperature distribution enhances the increasing values of particle volume fraction in the case of aggregation effects of nanoparticles whereas temperature distribution lowers in the case of non-aggregation effect of nanoparticles. .
基金Supported by the National Natural Science Foundation of China(21776126)the National Basic Research Program of China(2015CB655301)+1 种基金the Natural Science Foundation of Jiangsu Province(BK20150063)partially supported by the Open Fund of State Key Laboratory of Separation Membranes and Membrane Processes(M1-201702).
文摘Fouling resistance of ultrafiltration(UF) membranes is critical for their long-term usages in terms of stable performance, so convenient approaches to prepare fouling-resistant membranes are always anticipated. Herein, we demonstrate the facile fabrication of antifouling polysulfone-block-poly(ethylene glycol)(PSF-b-PEG, SFEG)composite membranes. SFEG layer was coated onto macroporous supports and cavitated by immerging them in acetone/n-propanol following the mechanism of selective swelling induced pore generation. Thus-produced SFEG membranes possessed high permeance and excellent mechanical strength. Meanwhile, the structures and separation performances of the SFEG layers can be continuously tuned through simply changing swelling durations. More importantly, the hydrophilic PEG chains were spontaneously enriched onto the pore walls through swelling treatment, endowing intrinsic antifouling property to the SFEG membranes. Bovine serum albumin(BSA)/humic acid(HA) fouling tests proved the prominent fouling resistance of SFEG membranes, and the fouling resistance is expected to be long-standing because of the firm connection between PEG chains and PSF matrix by covalent bonding.
文摘Hydrogels composed of poly(vinyl alcohol)(PVA) and poly(ethylene glycol)(PEG) were synthesized using glutaraldehyde as crosslinker and investigated for controlled delivery of the common anti-inflammatory drug, ibuprofen(IBF). To regulate the drug delivery, solid inclusion complexes(ICs) of IBF in β–cyclodextrin(β–CD) were prepared and added to the hydrogels. The ICs were prepared by the microwave irradiation method, which is more environmentally benign. The formation of IC was confirmed by various analytical techniques and the synthesized hydrogels were also characterized. Controlled release of drug was achieved from the hydrogels containing the ICs in comparison to the rapid release from hydrogels containing free IBF.The preliminary kinetic analysis emphasized the crucial role of β–CD in the drug release process that influences the polymer relaxation, thereby leading to prolonged release. The cytotoxicity assay validated the hydrogels as non-toxic in nature and hence can be utilized for controlled delivery of IBF.
基金This work was supported by the National Basic Science Research and Development Grants (973) of China (No.G1999064705) and the National High Technology Project (863) of China (No. 2002AA326030).
文摘In order to improve the blood compatibility of silk fibroin (SF), poly(ethylene glycol) macromer (PEGM) in different amounts was added to the SF film to incorporate C=C group into the surface of blend films which were then modified by SO2 gas plasma treatment. ATR-FITR and XPS were used to analyze the chemical change which had occurred on the film's surface. When the content of sulfur on the surface of blend films surpasses 1.59%, the antithrombogenicity of plasma treated films increases remarkably due to surface sulfonation. This result implies that SF with blend of PEGM after SO2 plasma treatment have potential use for making blood-contacting biomaterials.
基金The authors are Indebted to the National Basic Science Rescarch and Development Grants(973)(No.1999054306).
文摘Poly (L-lactide)-poly(ethylene glycol) multiblock copolymers with predetermined block lengths were synthesized by polycondensation of PLA diols and PEG diacids. These copolymers presented special properties, such as better miscibility between the two components, low crystallinity and better hydrophilicity, which can be modulated by adjusting the block lengths of the two components.
基金supported by the 863 program(No.2006AA03Z233)973 program(No.2009CB623402) of China
文摘High density polyethylene （HDPE）/polyethylene-block-poly（ethylene glycol） （PE-b-PEG） blend porous membranes were prepared via thermally induced phase separation （TIPS） process using diphenyl ether （DPE） as diluent. The phase diagrams of HDPE/PE-b-PEG/DPE systems were determined by optical microscopy and differential scanning calorimetry （DSC）. By varying the content of PE-b-PEG, the effects of PE-b-PEG copolymer on morphology and crystalline structure of membranes were studied by scanning electron microscopy （SEM） and wide angle X-ray diffraction （WAXD）. The chemical compositions of whole membranes and surface layers were characterized by elementary analysis, Fourier transform infrared spectroscopy-attenuated total reflection （FTIR-ATR） and X-ray photoelectron spectroscopy （XPS）. Water contact angle, static protein adsorption and water flux experiments were used to evaluate the hydrophilicity, antifouling and water permeation properties of the membranes. It was found that the addition of PE-b-PEG increased the pore size of the obtained blend membranes. In the investigated range of PE-b-PEG content, the PEG blocks could not aggregate into obviously separated domains in membrane matrix. More importantly, PE-b-PEG could not only be retained stably in the membrane matrix during membrane formation, but also enrich at the membrane surface layer. Such stability and surface enrichment of PE-b-PEG endowed the blend membranes with improved hydrophilicity, protein absorption resistance and water permeation properties, which would be substantially beneficial to HDPE membranes for water treatment application.
基金Funded by the National Natural Science Foundation of China(No.51503041)the Natural Science Foundation of Fujian Province,China(No.2018J01752)
文摘Cassava residue was liquefied by using ethylene glycol(EG), ethylene carbonate, propylene carbonate and polyethylene glycol(molecular weight: 400 g/mol) as the liquefaction reagent respectively at the temperature of 130-170 ℃ with sulfuric acid as the catalyst. The influences of liquefaction parameters, such as the type of liquefaction reagents, mass ratio of EG/cassava residue, liquefaction temperature and time on the properties of the products were discussed. The optimum liquefaction conditions were obtained when the mass ratio of EG/cassava residue was 6:1(w/w), the liquefaction temperature was 150 ℃, the liquefaction time was3 h and the mass fraction of concentrated sulfuric acid/EG was 2.5 wt%. The hydroxyl numbers and residue content of the liquefied products at optimal conditions were 1 137 mgKOH/g and 0.43%, respectively. FT-IR spectrum showed that the liquefaction product of cassava residue was polyether polyol and could be used to prepare polyurethane material or alkyd resins.
基金Projects(51274108,21263007,51204080)supported by the National Natural Science Foundation of ChinaProject(2011FA009)supported by the Applied Research Foundation of Yunnan Province,ChinaProject(14118441)supported by the Talents Cultivation Foundation of Kunming University of Science and Technology,China
文摘The electrodeposition behaviors of nickel on glassy carbon（GC） and carbon steel（CS） electrodes were investigated in the14.3%-85.7%（mole fraction） betaine.HCl ethylene glycol（EG） ionic liquid using cyclic voltammetry and chronoamperometry.The results indicated that the reduction of Ni（Ⅱ） on CS electrode via a diffusion-controlled quasi-reversible process was much more facile and easier than that occurred on GC electrode,which followed a diffusion-controlled three-dimensional instantaneous nucleation and growth.Scanning electron microscopy was used to observe that the deposit was dense and contained fine crystallites with average size of（80±4） nm.Energy dispersive spectrometer analysis showed that the obtained deposit was metallic nickel.X-ray diffraction spectroscopy indicated that（111） plane was the most preferred crystal orientation.The nickel deposit was luminous and bright,and had good adhesion with the CS substrate.
基金Henan Innovation Project for University Prominent Research Talents(“HAIPURT”)program.
文摘The ternary hybrid films consisting of chitosan(CS),polyethylene glycol(PEG)and nano-sized silica which was surface-modified by amino groups(RNSA)were prepared.The structures of the blend membranes were characterized by attenuation total reflection-infrared spectroscopy(ATR-IR),X-ray diffraction(XRD),optical microscopy(OM)and differential scanning calorimetry(DSC).The results showed that the addition of silica affected not only the distribution and crystallinity of PEG on the sample surface,but also the pha...
基金support from the National Natural Science Foundation of China(No. 20134020)the Visiting Scholar Project of Shandong Province of China(No.20081001)the Science Research Fund of Shandong Jiaotong University of China(No.Z200802)
文摘Novel Y-shaped block copolymers of poly（ethylene glycol） and poly（N-isopropylacrylamide）, PEG-b-（PNIPAM）2, were successfully synthesized through atom transfer radical polymerization （ATRP）. A difunctional macroinitiator was prepared by esterification of 2,2-dichloroacetyl chloride with poly（ethylene glycol） monomethyl ether （PEG）. The copolymers were obtained via the ATRP ofN-isopropylacrylamide （NIPAM） at 30℃ with CuCl/Me6TREN as a catalyst system and DMF/H2O （v/v = 3：1） mixture as solvent. The resulting copolymers were characterized by gel permeation chromatography （GPC） and ^1H NMR. These block copolymers show controllable molecular weights and narrow molecular weight distributions （PDI 〈 1.15）. Their phase transition temperatures and the corresponding enthalpy changes in aqueous solution were measured by differential scanning calorimetry （DSC）. As a result, the phase transition temperature of PEG45-b-（PNIPAM55）2 is higher than that of PNIPAM, however, the corresponding enthalpy change is much lower, indicating the significant influence of the macromolecular composition and architecture on the phase transition.
文摘Porous polyvinylidene fluoride-co-hexafluropropylene(PVDF-HFP)hollow fiber membranes were fabricated through a wet spinning process.In order to improve the membrane structure,composition of the polymer solution was adjusted by studying ternary phase diagrams of polymer/solvent/non-solvent.The prepared membranes were used for sweeping gas membrane distillation(SGMD)of 20 wt% ethylene glycol(EG)aqueous solution.The membranes were characterized by different tests such as N2 permeation,overall porosity,critical water entry pressure(CEPw),water contact angle and collapsing pressure.From FESEM examination,addition of 3 wt% glycerol in the PVDF-HFP solution,produced membranes with smaller finger-likes cavities,higher surface porosity and smaller pore sizes.Increasing the polymer concentration up to 21 wt% resulted in a dense spongy structure which could significantly reduce the N2 permeance.The membrane prepared by 3 wt% glycerol and 17 wt% polymer demonstrated an improved structure with mean pore size of 18 nm and a high surface porosity of 872 m^−1.CEPw of 350 kPa and overall porosity of 84% were also obtained for the improved membrane.Collapsing pressure of the membranes relatively improved by increasing the polymer concentration.From the SGMDtest,the developed membrane represented a maximumpermeate flux of 28 kg·m^−2·h^−1 which is almost 19% higher than the flux of plain membrane.During 120 h of a long-termSGMD operation,a gradual flux reduction of 30% was noticed.In addition,EG rejection reduced from 100% to around 99.5% during 120 h of the operation.
基金The project was supported by the National Natural Science Foundation of China(No.29774034).
文摘Poly-dl-lactide-poly(ethylene glycol) (PELA) triblock copolymers were synthesized with lanthanum acetate as the initiator. PELA microspheres with entrapped Vibrio Cholera antigen and outer membrane protein (OMP) were prepared by a double emulsion W/O/W based on solvent extraction methods. The obtained microspheres showed smooth and spherical surface and their size varied between 0.5 and 5.0 mu m, which are suitable for oral targeting delivery system. The distribution tests in rabbits and mice through scanning electronic micrography and fluorescence microscope indicated that microspheres have successfully reached the immunization-related tissues, such as the liver, spleen and intestinal peyer's patches, following oral administration. The PELA microspheres were also evaluated as an efficient antigen delivery system by enhancing a higher protective ratio against live Vibrios Cholera.
基金The authors gratefully acknowledge to ANP(Brazilian Petroleum National Agency)COLFUTURO(Foundation for the future of Colombia)for the financial support.
文摘The mechanism of the hydrophobized poly(ethylene glycol)(PEG)/K^(+) system inhibiting shale hydration was studied by laboratory experiment. The inhibition performance was evaluated through cuttings hot-rolling dispersion, bentonite inhibition and contact angle tests. The inhibition became stronger as contact angle and PEG concentration increased. A modified cuttings hot-rolling dispersion experiment suggested that these molecular systems did not act through the thermally activated mud emulsion(TAME) mechanism. The interaction of the PEG/K^(+) with clay samples was investigated through adsorption studies and by Fourier transform infrared spectroscopy(FT-IR), X-ray diffraction(XRD) and thermogravimetric analysis(TGA). The adsorption isotherms showed that the presence of K^(+) increased the PEG affinity for the clay surface. This inhibition effect was accompanied by a reduction of the bentonite hydration with PEG adsorption, evidenced by FT-IR, TGA and differential thermogravimetric(DTG) curves. XRD patterns were conclusive in showing that the presence of K^(+) ions limited the expansion of the clay interlamellar region to only one PEG layer, and the terminal hydrophobic segments of the PEG chains turned out to be determinant in enhancement of the inhibitory efficiency. The cuttings hot-rolling dispersion was carried out on water-base drilling fluid with PEG/K^(+), which proved the inhibition performance of PEG/K^(+) in oil field drilling.
文摘Two-dimensional nuclear overhauser enhancement (2D NOESY)measurements show that sodium dodecyl sulfonate SDSN molecules co-aggregate with poly-ethylene glycol PEG in their aqueous solution at a concentration range of SDSN between the so-called co-aggregation concentration (cac) and the. Normal critical micellar concentration (cmc). SDSN micelles are formed when the cmc of SDSN is reached with PEG uniformly distributed in the interior.
文摘Lactide was synthesized using lactic acid and stannous octoate as raw material and catalyst, respectively. Poly(lactic acid)-poly(ethylene glycol) (PLA-PEG) was prepared by lactide and poly (ethylene glycol) (PEG) via ring-opening polymerization. The most appropriate technological conditions of synthesis of lactide were researched in the paper. The copolymers were measured by Infrared spectroscopy (IR) and <sup>1</sup>H nuclear magnetic resonance (<sup>1</sup>H NMR). The results proved that the lactide and PLA-PEG were synthesized successfully. Hydrophilic performance of the copolymer was measured by a water contact angle tester after prepared into a flat membrane. The water contact angle changed from 81.5? to 71.6?, which proved that the hydrophily of PLA-PEG was better than PLA.
