The non-isothermal crystallization kinetics, isothermal crystallization and the morphology of crystals of the copolymer poly (ethylene terephthalate/ isophthalate )(IPET) were studied by DSC and polarized-light micros...The non-isothermal crystallization kinetics, isothermal crystallization and the morphology of crystals of the copolymer poly (ethylene terephthalate/ isophthalate )(IPET) were studied by DSC and polarized-light microscopy in this paper. DSC results indicate that the glass transition temperature Tg of IPET is slightly lower than that of poly(ethylene terephthalate) (PET), but the melting temperature Tm and the crystallization temperature Tc of PET and IPET have much difference.The difference of Tc between PET and IPET2 is about 7℃, and the difference of Tm between PET and IPET2 is about 16℃. From the kinetics analysis of the crystallization, the crystallization mechanism of all samples is of three-dimension spherulitic growth from instantaneous nuclei and the incorporation of isophthalate (IPA) decreases the crystallization rate of IPET greatly. The isothermal results indicate that the morphologies of PET and IPET crystals are all spherulite, which is in conformity to the results of nonisothermal dynamic crystallization. At the same time,the spherulite of IPET grows slower and has longer incubation time than the spherulite of PET under the same crystallization condition.展开更多
A phosphorus-containing monomer (lO-oxo-10-hydro-9-oxa-10λ^5-phosphaphenanthrene-10-yl)-methyl acrylate (MD was copolymerized with styrene to give a potential flame retardant copolymer of high thermal stability. T...A phosphorus-containing monomer (lO-oxo-10-hydro-9-oxa-10λ^5-phosphaphenanthrene-10-yl)-methyl acrylate (MD was copolymerized with styrene to give a potential flame retardant copolymer of high thermal stability. The structures of monomer and copolymer were characterized by FT-IR and ^1H NMR measurements. The reactivity ratios for free-radical of the monomer (M1) and styrene (Mz) were studied. The calculated results are as follows: r1 = 0.225, r2 = 0.503; Q1 = 0.413, e1 = 0.476; azeotropic point = 0.37. TGA and DTG curves indicated that Ml is a potential flame retarding monomer for styrenic polymers. C 2009 Yu Bin Zheng. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.展开更多
Six samples of linear high randomness 60PHB/ PET thermotropic liquid crystal copolyesters are made by melt copolymerization at 290℃ , whose randomness about 0.955 is measured by the discernible ’H-NMR spectrometer. ...Six samples of linear high randomness 60PHB/ PET thermotropic liquid crystal copolyesters are made by melt copolymerization at 290℃ , whose randomness about 0.955 is measured by the discernible ’H-NMR spectrometer. High tenacity, high module fiber is prepared by melt spinning in liquid crystal phase. The effect of molecular weight, shear rate, temperature as well as spinning drawn ratio on the mechanical behavior of 60PHB / PET copolyester fiber are shown that, lower shear rate (2<sup> </sup>10 s<sup>-1</sup>), higher temperature melting (300℃ ), lower temperature spinning (280℃ ) and higher molecular weight are favourable to the increase of the fiber mechanical properties. With the variance of drawn ratio, fiber mechanical property has a transition point due to traversion from shear-orientation to drawn-orientation. The copolyester fiber has high crystallinity, high orientation at the crystalline region, high chain orientation and high regular fibrillar structure.展开更多
The microemulsion polymerization of methyl methacrylate was studied. The effects of feeding modes on the structure and the properties of the obtained polymer microlatex were investigated by measuring the conversion, t...The microemulsion polymerization of methyl methacrylate was studied. The effects of feeding modes on the structure and the properties of the obtained polymer microlatex were investigated by measuring the conversion, the transmittance and the refractive index of the latex, and by measuring the particle size, the molecular weight and the glass transition temperature (T_g) of the polymers. The results show that compared to the batch feeding mode, the semi-continuous feeding mode is more favorable to form a PMMA microlatex with a higher transmittance, a smaller particle size, a higher molecular weight and a higher T_g. And the obtained PMMA microlatex has a 30%—40% (mass fraction) polymer content, a 0. 03 emulsifier/water weight ratio, a 0. 05 emulsifier/monomer weight ratio and a 17 nm average particle diameter, which is very important for the industrialization of the microemulsion polymerization technique.展开更多
Polyacrylic acid particles in nano-scale were synthesized using an inverse (W/O) emulsion polymerization method. The particle size and size change of inverse micelles which solubilize a part of monomer solution was mo...Polyacrylic acid particles in nano-scale were synthesized using an inverse (W/O) emulsion polymerization method. The particle size and size change of inverse micelles which solubilize a part of monomer solution was monitored by PCS (photon correlation spectroscopy) and the particles of polyacrylic acid were viewed in scanning electron microscope for the first time. It was concluded that the inverse micelles were primarily the polymerization reaction sites.展开更多
It is of significance to construct continuous multiphase percolation channels with fast lithium-ion pathway in hybrid solid electrolytes.3D ceramic nanostructure frameworks have attracted great attention in this field...It is of significance to construct continuous multiphase percolation channels with fast lithium-ion pathway in hybrid solid electrolytes.3D ceramic nanostructure frameworks have attracted great attention in this field.Herein,the three-dimensional perovskite Li_(0.33)La_(0.557)TiO_(3)nanotubes framework(3D-LLTO-NT)is fabricated via a facile coaxial electro-spinning process followed by a calcination process at 800°C.The hybrid polymer electrolyte of 3DLLTO-NT framework and poly(ethylene carbonate)(3D-LLTO-NT@PEC)shows improved ionic conductivity of 1.73×10^(-4)S cm^(-1)at ambient temperature,higher lithium-ion transference number(t_(Li)^(+))of 0.78 and electrochemical stability window up to 5.0 V vs Li/Li^(+).The all-solid-state cell of LiFePO_(4)/3D-LLTO-NT@PEC/Li delivers a high specific capacity of 140.2 mAh g^(-1)at 0.1 C at ambient temperature.This outstanding performance is attributed to the 3D ceramic nanotubes frameworks which provide fast lithium ion transfer pathway and stable interfaces.展开更多
Chloromethylated poly(phthalazinone ether sulfone ketone) (CMPPESK) was prepared from poly(phthalazinone ether sulfone ketone) (PPESK) using chloromethyl octyl ethers (CMOE) with lower toxicity as chlorometh...Chloromethylated poly(phthalazinone ether sulfone ketone) (CMPPESK) was prepared from poly(phthalazinone ether sulfone ketone) (PPESK) using chloromethyl octyl ethers (CMOE) with lower toxicity as chloromethylated regent. CMPPESK was soluble in N-methyl-2-pyrrolidone (NMP), N,N-dimethylacetamide (DMAc) and chloroform. Quaternized poly(phthalazinone ether sulfone ketone) (QAPPESK) was prepared from CMPPESK by quaternization. QAPPESK had excellent solvent resistance, which was only partly soluble in sulfuric acid (98%) and swollen in N,N-dimethylformamide (DMF). The vanadium redox flow battery (V-RFB) using QAPPESK anion-exchange membrane had better performance with 88.3% of overall energy efficiency.展开更多
Eight complexes of rare earth with 2 mercaptobenthiazole, RELCl 2·RE(OH) 3· x H 2O (L=2 mercaptobenthiazole, RE= La~Gd, Y, except for Pm, x =0, 2~4), were synthesized in unhydrous ethanol and char...Eight complexes of rare earth with 2 mercaptobenthiazole, RELCl 2·RE(OH) 3· x H 2O (L=2 mercaptobenthiazole, RE= La~Gd, Y, except for Pm, x =0, 2~4), were synthesized in unhydrous ethanol and characterized by elemental analyses, IR spectra and thermal analyses. The results show that the ligand is coordinated to the RE ion through both the exocyclic sulfur and the thiazole nitrogen. The vulcanizing properties of the La complex as accelerator were studied in the traditional tire rubber, which indicate that the cross linked rubber accelerated by the rare earth complex has good physical and dynamic mechanical properties by comparison.展开更多
The oxides Eu, Ho, Er and Dy were used to prepare the hydroxides of rare earth modified carbon black. Then natural rubber latex (NRL) was added into the reactor. The system reacted at 85 ℃ with stirring for 1 h to ...The oxides Eu, Ho, Er and Dy were used to prepare the hydroxides of rare earth modified carbon black. Then natural rubber latex (NRL) was added into the reactor. The system reacted at 85 ℃ with stirring for 1 h to prepare powdered HAF-Ln(OH)3/NR composites. The effects of the kind and content of Ln on the particle size distribution of P [ NR/HAF-Ln (OH)3 ] and mechanical properties of its vulcanizate were studied respectively. It is found that rare earth can help to get the powder of the composite, the product particle with a diameter less than 0.9mm will be get when the composites containing the compound of Ho, Er and Dy with dosage of 1.0, 1.0, O. 5 percent, respectively. The adding of Ln can improve the tensile strength and tear strength of the vulcanizate effectively, what's more, Er and Dy can decrease the permanent set of vulcanizate significantly. The SEM studies shows that P[ NR/HAF-Dy (OH)3 ] vulcanizate shows superior mechanical properties that depend primarily on the absence of free carbon black, the fine dispersion of carbon black in the rubber matrix and better polymer-filler interaction.展开更多
The structures and properties of benzoxazines were investigated by virtue of molecular modeling at a molecular level. By means of Cerius software(version 4.0) supplied by Molecular Simulations Inc., the molecular mech...The structures and properties of benzoxazines were investigated by virtue of molecular modeling at a molecular level. By means of Cerius software(version 4.0) supplied by Molecular Simulations Inc., the molecular mechanics and the molecular dynamics were performed under a PCFF force field. Five kinds of the polymeric chains of benzoxazines were created by using polymer builder and energy minimization. The relaxation process was conducted with both energy minimization and molecular dynamics.展开更多
A novel geminal imidazolium ionic liquid with long hydrocarbon group, 1,4-bis (3-tetradecylimidazolium- 1-yl) butane bromide was synthesized and an efficient synthesized method was introduced detailedly. Its structu...A novel geminal imidazolium ionic liquid with long hydrocarbon group, 1,4-bis (3-tetradecylimidazolium- 1-yl) butane bromide was synthesized and an efficient synthesized method was introduced detailedly. Its structure was determined by FT-IR, ^1H NMR and elemental analysis.展开更多
A side-chain liquid crystalline ionomer(SLCI) was synthesized by grafting copolymerization of 4-(4-ethoxybenzoyloxy)-4'-allyloxybiphenyl and N-allyl-pyridium bromide on polymethylhydrosiloxane. The SLCI was blend...A side-chain liquid crystalline ionomer(SLCI) was synthesized by grafting copolymerization of 4-(4-ethoxybenzoyloxy)-4'-allyloxybiphenyl and N-allyl-pyridium bromide on polymethylhydrosiloxane. The SLCI was blended with polypropylene(PP) and polybutylene terephthalate(PBT) by melt mixing. The thermal behavior, liquid crystalline properties, morphological structure, and mechanical properties of the blends were investigated by differential scanning calorimetry(DSC), polarizing optical microscopy(POM), scanning electron microscopy(SEM), and tensile measurement. When a proper amount of SLCI was added, fine configurations were formed in the PBT/PP/SLCI blend system, and the mechanical properties were improved due to improved adhesion at the interface. When excess SLCI was added, an inhomogeneous structure resulted, which caused the mechanical properties to deteriorate.展开更多
The electrorheological properties of a model system consisting of metal particles with insulating coating in a dielectric oil are analyzed by extending Rayleigh identity based on a multipole expansion theory.Evaluatio...The electrorheological properties of a model system consisting of metal particles with insulating coating in a dielectric oil are analyzed by extending Rayleigh identity based on a multipole expansion theory.Evaluation of the effective dielectric constant is emphasized.The dependence of the shear stressтon the shear strainθand the shear modulus G for the electrorheological solid is presented.It is found that the model system shows much higher electrorheological performance than the traditional suspensions.展开更多
Luminescent porous materials have shown various applications such as electronic devices, gas adsorption, energy materials and photocatalysis. Consequently, we designed and prepared a new type borondipyrromethene(BODIP...Luminescent porous materials have shown various applications such as electronic devices, gas adsorption, energy materials and photocatalysis. Consequently, we designed and prepared a new type borondipyrromethene(BODIPY) based porous organic polymer(POP) by using Sonogashira coupling reaction. This POP-1 exhibits high thermal stability with moderate surface area. In addition, POP-1 is highly emissive in a solid state. Due to enrichment of different kinds of heteroatoms in the skeleton of the porous polymer, POP-1 selectively captures carbon dioxide(CO_2) with relative high adsorption selectivity of CO_2/N_2.展开更多
Essential oils (EOs) are the volatile lipophilic components extracted from plants. Many EOs have demonstrated strong antimicrobial properties when tested in in vitro experiments. The commercial applications of these E...Essential oils (EOs) are the volatile lipophilic components extracted from plants. Many EOs have demonstrated strong antimicrobial properties when tested in in vitro experiments. The commercial applications of these EOs require a suitable formulation constituted by biodegradable compounds that protect them from degradation and evaporation at the same time that allows for a sustained release. The objective of this study was therefore to reduce the rate of evaporation of the oil via microencapsulation. Alginate microspheres (AMSs) were prepared using emulsion extrusion method. The AMSs were hardened with a cross-linking agent, calcium chloride. The effects of the three variables: alginate concentration (0.5% - 8%), the amount of cross-linking agent (0.125% - 2%) and time of cross-linking (5 - 30 min.) on loading capacity and encapsulation efficiency (EE, %) were studied. The effect of the amount of cross-linker was significant on loading capacity (%) and EE (%). The AMSs under the optimized conditions provided loading capacity of 22% - 24% and EE of 90% - 94% based on type of EO. The antifungal activity of vapors of microencapsulated and non-microencapsulated oils were evaluated against two of pathogenic fungi species for stored grains: Aspergillus niger and Fusarium verticillioides. The optimized MSs were observed to have a sustained in vitro release profile (50% of the antifungal activity was maintained at the 8th day of the study). In conclusion, encapsulation in Ca-alginate microspheres may effectively reduce the evaporation rate of essential oils, thus?increase the potential antifungal activity.展开更多
Two crosslinkable poly(p-phenyleneethynylene)s(PPEs): poly[2,5-di(2'-ethyl-hexyloxy)-1,4-phenylenecthynylene] with end-capped vinyl(PPE1) and poly[2,5-di(allyloxy)-1,4-phenyleneethynylene-2,5-di(2'-ethyl...Two crosslinkable poly(p-phenyleneethynylene)s(PPEs): poly[2,5-di(2'-ethyl-hexyloxy)-1,4-phenylenecthynylene] with end-capped vinyl(PPE1) and poly[2,5-di(allyloxy)-1,4-phenyleneethynylene-2,5-di(2'-ethyl-hexyloxy)-1,4-phenyleneethynylene](PPE2) were synthesized. Via the thermal addition reactions of vinyl end groups of PPE1 and allyloxy side groups of PPE2, crosslinked polymers C-PPE1 and C-PPE2 were obtained, respectively. The two polymers were characterized by wide-angle X-ray diffraction(WXRD), ultraviolet-visible(UV-Vis) absorption, and photoluminescence(PL). The results indicate that in the solid state, the polymer chains of PPE1 were packed with a low degree of crystallinity because of the sterically hindered(2'-ethyl-hexyl)oxy branched side chains, but, because of the introduction of allyloxy side chains, the polymer chains of PPE2 were packed in an order fashion with a high degree of crystallinity. Because of the high crosslinking density in C-PPE2, the formation of aggregates and excimer was hampered by the formed crosslinking network more effectively in C-PPE2 film than in C-PPE1 film.展开更多
A main-chain liquid crystalline ionomer(MLCI) containing sulfonic group was synthesized by an interfacial condensation reaction.The MLCI was blended with polybutylene terephthalate(PBT) and polypropylene(PP).MLC...A main-chain liquid crystalline ionomer(MLCI) containing sulfonic group was synthesized by an interfacial condensation reaction.The MLCI was blended with polybutylene terephthalate(PBT) and polypropylene(PP).MLCI interacted with both the dispersed(PP) phase and the matrix(PBT) phase to modify the interfacial interaction of PBT and PP.Differential scanning calorimetry(DSC),scanning electron microscopy(SEM) and FTIR imaging system analysis demonstrated the significance of interfacial interaction in the polymer blends.MLCI brought about good adhesion at the interfacial,which reduced the disperse phase size and enabled a fine PP phase at matrix.The mechanical properties of the ternary blends were improved when a proper amount of MLCI was added.This was attributed to enhanced adhesion at the interface,which invoked better mechanical properties in the blends.展开更多
N,N'-Bis(3-hydroxyphenyl)-1,8,4,5-naphthalenetetracarboxylic bisimide was prepared from the reaction of 1,8,4,5-naphthalenetetrcarboxylic acid dianhydride and 2-aminophenol in N, N-dimethylformamide. Polymerization...N,N'-Bis(3-hydroxyphenyl)-1,8,4,5-naphthalenetetracarboxylic bisimide was prepared from the reaction of 1,8,4,5-naphthalenetetrcarboxylic acid dianhydride and 2-aminophenol in N, N-dimethylformamide. Polymerization of this bisimide with 4,4'-difluorodiphenylsulfone and disodium 3,3'-disulfonate4,4'-difluorodiphenylsulfone gave ion-exchange sulfonated poly(ether sulfone). The structure of the title compound was characterized with H-NMR and its polymer was characterized with FT-IR.展开更多
A series of shape memory polyurethane elastomers(SMPUs) were synthesized by altering the chain extenders.The reaction was proceeding by solution prepolymerization method.Infrared spectra(IR),Differential scanning calo...A series of shape memory polyurethane elastomers(SMPUs) were synthesized by altering the chain extenders.The reaction was proceeding by solution prepolymerization method.Infrared spectra(IR),Differential scanning calorimetry(DSC) and specific viscosity method were carried out to examine the structure,glass transition temperature(Tg) and molecular weight of these SMPUs.The shape memory abilities and tensile properties of the material were investigated simultaneously.The IR results showed that the SMPUs were successfully synthesized and the Tg of the samples were all above 45 ℃ according to the DSC test.All the samples can recover to its original shape completely after bending to 180°.Tensile properties were tested on the samples.The sample MDI/PBAG/BDO with the mole ratio 4/1/3 gets the best tensile strength and highest ultimate elongation.展开更多
A series of thermoreversible konjac glucomannan gels crosslinked by organic borate were prepared. Required amount of hydrophilic SiO2 was added into the konjac glucomannan solutions before the crosslinking reaction, T...A series of thermoreversible konjac glucomannan gels crosslinked by organic borate were prepared. Required amount of hydrophilic SiO2 was added into the konjac glucomannan solutions before the crosslinking reaction, The gel network was formed through the crosslinking reaction between borate ions dissociated from organic borate and the cis-diol hydroxyl groups on the mannose units of polysaccharide chains. The rheological properties of the complex gels were studied by dynamic viscoelastic measurement. The gelation kinetics of the complex gels was studied and the critical getation points of the gels were exactly determined by the Winter-Chambon criterion. The effects of temperature and composite ratio on the shear storage modulus (G'), the loss modulus (G") and the sol-gel transition points were investigated.展开更多
文摘The non-isothermal crystallization kinetics, isothermal crystallization and the morphology of crystals of the copolymer poly (ethylene terephthalate/ isophthalate )(IPET) were studied by DSC and polarized-light microscopy in this paper. DSC results indicate that the glass transition temperature Tg of IPET is slightly lower than that of poly(ethylene terephthalate) (PET), but the melting temperature Tm and the crystallization temperature Tc of PET and IPET have much difference.The difference of Tc between PET and IPET2 is about 7℃, and the difference of Tm between PET and IPET2 is about 16℃. From the kinetics analysis of the crystallization, the crystallization mechanism of all samples is of three-dimension spherulitic growth from instantaneous nuclei and the incorporation of isophthalate (IPA) decreases the crystallization rate of IPET greatly. The isothermal results indicate that the morphologies of PET and IPET crystals are all spherulite, which is in conformity to the results of nonisothermal dynamic crystallization. At the same time,the spherulite of IPET grows slower and has longer incubation time than the spherulite of PET under the same crystallization condition.
文摘A phosphorus-containing monomer (lO-oxo-10-hydro-9-oxa-10λ^5-phosphaphenanthrene-10-yl)-methyl acrylate (MD was copolymerized with styrene to give a potential flame retardant copolymer of high thermal stability. The structures of monomer and copolymer were characterized by FT-IR and ^1H NMR measurements. The reactivity ratios for free-radical of the monomer (M1) and styrene (Mz) were studied. The calculated results are as follows: r1 = 0.225, r2 = 0.503; Q1 = 0.413, e1 = 0.476; azeotropic point = 0.37. TGA and DTG curves indicated that Ml is a potential flame retarding monomer for styrenic polymers. C 2009 Yu Bin Zheng. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.
文摘Six samples of linear high randomness 60PHB/ PET thermotropic liquid crystal copolyesters are made by melt copolymerization at 290℃ , whose randomness about 0.955 is measured by the discernible ’H-NMR spectrometer. High tenacity, high module fiber is prepared by melt spinning in liquid crystal phase. The effect of molecular weight, shear rate, temperature as well as spinning drawn ratio on the mechanical behavior of 60PHB / PET copolyester fiber are shown that, lower shear rate (2<sup> </sup>10 s<sup>-1</sup>), higher temperature melting (300℃ ), lower temperature spinning (280℃ ) and higher molecular weight are favourable to the increase of the fiber mechanical properties. With the variance of drawn ratio, fiber mechanical property has a transition point due to traversion from shear-orientation to drawn-orientation. The copolyester fiber has high crystallinity, high orientation at the crystalline region, high chain orientation and high regular fibrillar structure.
基金Supported by the National Natural Science Foundation of China(No. 29974021) and the Educational Ministry of China.
文摘The microemulsion polymerization of methyl methacrylate was studied. The effects of feeding modes on the structure and the properties of the obtained polymer microlatex were investigated by measuring the conversion, the transmittance and the refractive index of the latex, and by measuring the particle size, the molecular weight and the glass transition temperature (T_g) of the polymers. The results show that compared to the batch feeding mode, the semi-continuous feeding mode is more favorable to form a PMMA microlatex with a higher transmittance, a smaller particle size, a higher molecular weight and a higher T_g. And the obtained PMMA microlatex has a 30%—40% (mass fraction) polymer content, a 0. 03 emulsifier/water weight ratio, a 0. 05 emulsifier/monomer weight ratio and a 17 nm average particle diameter, which is very important for the industrialization of the microemulsion polymerization technique.
文摘Polyacrylic acid particles in nano-scale were synthesized using an inverse (W/O) emulsion polymerization method. The particle size and size change of inverse micelles which solubilize a part of monomer solution was monitored by PCS (photon correlation spectroscopy) and the particles of polyacrylic acid were viewed in scanning electron microscope for the first time. It was concluded that the inverse micelles were primarily the polymerization reaction sites.
基金financial support from Key Scientific and Technological Project of Wuhan City(Grant no.2018010401011279)Team Innovation Foundation of Hubei province(Grant no.T201935)National Natural Science Foundation of China(Grant nos.51872127,22209059 and 22139001)
文摘It is of significance to construct continuous multiphase percolation channels with fast lithium-ion pathway in hybrid solid electrolytes.3D ceramic nanostructure frameworks have attracted great attention in this field.Herein,the three-dimensional perovskite Li_(0.33)La_(0.557)TiO_(3)nanotubes framework(3D-LLTO-NT)is fabricated via a facile coaxial electro-spinning process followed by a calcination process at 800°C.The hybrid polymer electrolyte of 3DLLTO-NT framework and poly(ethylene carbonate)(3D-LLTO-NT@PEC)shows improved ionic conductivity of 1.73×10^(-4)S cm^(-1)at ambient temperature,higher lithium-ion transference number(t_(Li)^(+))of 0.78 and electrochemical stability window up to 5.0 V vs Li/Li^(+).The all-solid-state cell of LiFePO_(4)/3D-LLTO-NT@PEC/Li delivers a high specific capacity of 140.2 mAh g^(-1)at 0.1 C at ambient temperature.This outstanding performance is attributed to the 3D ceramic nanotubes frameworks which provide fast lithium ion transfer pathway and stable interfaces.
基金partly financed by the Major State Basic Research Development Program of China(No.2003 CB615700)the National Natural Science Foundation of China(No.20604005).
文摘Chloromethylated poly(phthalazinone ether sulfone ketone) (CMPPESK) was prepared from poly(phthalazinone ether sulfone ketone) (PPESK) using chloromethyl octyl ethers (CMOE) with lower toxicity as chloromethylated regent. CMPPESK was soluble in N-methyl-2-pyrrolidone (NMP), N,N-dimethylacetamide (DMAc) and chloroform. Quaternized poly(phthalazinone ether sulfone ketone) (QAPPESK) was prepared from CMPPESK by quaternization. QAPPESK had excellent solvent resistance, which was only partly soluble in sulfuric acid (98%) and swollen in N,N-dimethylformamide (DMF). The vanadium redox flow battery (V-RFB) using QAPPESK anion-exchange membrane had better performance with 88.3% of overall energy efficiency.
文摘Eight complexes of rare earth with 2 mercaptobenthiazole, RELCl 2·RE(OH) 3· x H 2O (L=2 mercaptobenthiazole, RE= La~Gd, Y, except for Pm, x =0, 2~4), were synthesized in unhydrous ethanol and characterized by elemental analyses, IR spectra and thermal analyses. The results show that the ligand is coordinated to the RE ion through both the exocyclic sulfur and the thiazole nitrogen. The vulcanizing properties of the La complex as accelerator were studied in the traditional tire rubber, which indicate that the cross linked rubber accelerated by the rare earth complex has good physical and dynamic mechanical properties by comparison.
文摘The oxides Eu, Ho, Er and Dy were used to prepare the hydroxides of rare earth modified carbon black. Then natural rubber latex (NRL) was added into the reactor. The system reacted at 85 ℃ with stirring for 1 h to prepare powdered HAF-Ln(OH)3/NR composites. The effects of the kind and content of Ln on the particle size distribution of P [ NR/HAF-Ln (OH)3 ] and mechanical properties of its vulcanizate were studied respectively. It is found that rare earth can help to get the powder of the composite, the product particle with a diameter less than 0.9mm will be get when the composites containing the compound of Ho, Er and Dy with dosage of 1.0, 1.0, O. 5 percent, respectively. The adding of Ln can improve the tensile strength and tear strength of the vulcanizate effectively, what's more, Er and Dy can decrease the permanent set of vulcanizate significantly. The SEM studies shows that P[ NR/HAF-Dy (OH)3 ] vulcanizate shows superior mechanical properties that depend primarily on the absence of free carbon black, the fine dispersion of carbon black in the rubber matrix and better polymer-filler interaction.
基金Supported by the National Natural Science Foundation of China(No. 5 95 730 0 8) .
文摘The structures and properties of benzoxazines were investigated by virtue of molecular modeling at a molecular level. By means of Cerius software(version 4.0) supplied by Molecular Simulations Inc., the molecular mechanics and the molecular dynamics were performed under a PCFF force field. Five kinds of the polymeric chains of benzoxazines were created by using polymer builder and energy minimization. The relaxation process was conducted with both energy minimization and molecular dynamics.
文摘A novel geminal imidazolium ionic liquid with long hydrocarbon group, 1,4-bis (3-tetradecylimidazolium- 1-yl) butane bromide was synthesized and an efficient synthesized method was introduced detailedly. Its structure was determined by FT-IR, ^1H NMR and elemental analysis.
基金Supported by the National Natural Science Foundation of China(No50673105)
文摘A side-chain liquid crystalline ionomer(SLCI) was synthesized by grafting copolymerization of 4-(4-ethoxybenzoyloxy)-4'-allyloxybiphenyl and N-allyl-pyridium bromide on polymethylhydrosiloxane. The SLCI was blended with polypropylene(PP) and polybutylene terephthalate(PBT) by melt mixing. The thermal behavior, liquid crystalline properties, morphological structure, and mechanical properties of the blends were investigated by differential scanning calorimetry(DSC), polarizing optical microscopy(POM), scanning electron microscopy(SEM), and tensile measurement. When a proper amount of SLCI was added, fine configurations were formed in the PBT/PP/SLCI blend system, and the mechanical properties were improved due to improved adhesion at the interface. When excess SLCI was added, an inhomogeneous structure resulted, which caused the mechanical properties to deteriorate.
基金Supported by the National Natural Science Foundation of China under Grant No.19874021in part by the Foundation of Educational Commit tee of Hu'nan Province of China under Grant No.98B087.
文摘The electrorheological properties of a model system consisting of metal particles with insulating coating in a dielectric oil are analyzed by extending Rayleigh identity based on a multipole expansion theory.Evaluation of the effective dielectric constant is emphasized.The dependence of the shear stressтon the shear strainθand the shear modulus G for the electrorheological solid is presented.It is found that the model system shows much higher electrorheological performance than the traditional suspensions.
基金Funded by the Natural Science Foundation of China(Nos.21674129 and 21376272)the Post-doctor Foundation of Central South University(No.140050292)
文摘Luminescent porous materials have shown various applications such as electronic devices, gas adsorption, energy materials and photocatalysis. Consequently, we designed and prepared a new type borondipyrromethene(BODIPY) based porous organic polymer(POP) by using Sonogashira coupling reaction. This POP-1 exhibits high thermal stability with moderate surface area. In addition, POP-1 is highly emissive in a solid state. Due to enrichment of different kinds of heteroatoms in the skeleton of the porous polymer, POP-1 selectively captures carbon dioxide(CO_2) with relative high adsorption selectivity of CO_2/N_2.
文摘Essential oils (EOs) are the volatile lipophilic components extracted from plants. Many EOs have demonstrated strong antimicrobial properties when tested in in vitro experiments. The commercial applications of these EOs require a suitable formulation constituted by biodegradable compounds that protect them from degradation and evaporation at the same time that allows for a sustained release. The objective of this study was therefore to reduce the rate of evaporation of the oil via microencapsulation. Alginate microspheres (AMSs) were prepared using emulsion extrusion method. The AMSs were hardened with a cross-linking agent, calcium chloride. The effects of the three variables: alginate concentration (0.5% - 8%), the amount of cross-linking agent (0.125% - 2%) and time of cross-linking (5 - 30 min.) on loading capacity and encapsulation efficiency (EE, %) were studied. The effect of the amount of cross-linker was significant on loading capacity (%) and EE (%). The AMSs under the optimized conditions provided loading capacity of 22% - 24% and EE of 90% - 94% based on type of EO. The antifungal activity of vapors of microencapsulated and non-microencapsulated oils were evaluated against two of pathogenic fungi species for stored grains: Aspergillus niger and Fusarium verticillioides. The optimized MSs were observed to have a sustained in vitro release profile (50% of the antifungal activity was maintained at the 8th day of the study). In conclusion, encapsulation in Ca-alginate microspheres may effectively reduce the evaporation rate of essential oils, thus?increase the potential antifungal activity.
基金Supported by the National Natural Science Foundation of China(Nos.20771030 and 20671025)
文摘Two crosslinkable poly(p-phenyleneethynylene)s(PPEs): poly[2,5-di(2'-ethyl-hexyloxy)-1,4-phenylenecthynylene] with end-capped vinyl(PPE1) and poly[2,5-di(allyloxy)-1,4-phenyleneethynylene-2,5-di(2'-ethyl-hexyloxy)-1,4-phenyleneethynylene](PPE2) were synthesized. Via the thermal addition reactions of vinyl end groups of PPE1 and allyloxy side groups of PPE2, crosslinked polymers C-PPE1 and C-PPE2 were obtained, respectively. The two polymers were characterized by wide-angle X-ray diffraction(WXRD), ultraviolet-visible(UV-Vis) absorption, and photoluminescence(PL). The results indicate that in the solid state, the polymer chains of PPE1 were packed with a low degree of crystallinity because of the sterically hindered(2'-ethyl-hexyl)oxy branched side chains, but, because of the introduction of allyloxy side chains, the polymer chains of PPE2 were packed in an order fashion with a high degree of crystallinity. Because of the high crosslinking density in C-PPE2, the formation of aggregates and excimer was hampered by the formed crosslinking network more effectively in C-PPE2 film than in C-PPE1 film.
基金Supported by the High-Tech Research and Development Program of China(No.2006AA02Z291)the National Natural Science Foundation of China(No.50673105)
文摘A main-chain liquid crystalline ionomer(MLCI) containing sulfonic group was synthesized by an interfacial condensation reaction.The MLCI was blended with polybutylene terephthalate(PBT) and polypropylene(PP).MLCI interacted with both the dispersed(PP) phase and the matrix(PBT) phase to modify the interfacial interaction of PBT and PP.Differential scanning calorimetry(DSC),scanning electron microscopy(SEM) and FTIR imaging system analysis demonstrated the significance of interfacial interaction in the polymer blends.MLCI brought about good adhesion at the interfacial,which reduced the disperse phase size and enabled a fine PP phase at matrix.The mechanical properties of the ternary blends were improved when a proper amount of MLCI was added.This was attributed to enhanced adhesion at the interface,which invoked better mechanical properties in the blends.
基金This project is supported by the National Natural Science Foundation of China(No.20104001).
文摘N,N'-Bis(3-hydroxyphenyl)-1,8,4,5-naphthalenetetracarboxylic bisimide was prepared from the reaction of 1,8,4,5-naphthalenetetrcarboxylic acid dianhydride and 2-aminophenol in N, N-dimethylformamide. Polymerization of this bisimide with 4,4'-difluorodiphenylsulfone and disodium 3,3'-disulfonate4,4'-difluorodiphenylsulfone gave ion-exchange sulfonated poly(ether sulfone). The structure of the title compound was characterized with H-NMR and its polymer was characterized with FT-IR.
基金Funded by Program for New Century Excellent Talents in University
文摘A series of shape memory polyurethane elastomers(SMPUs) were synthesized by altering the chain extenders.The reaction was proceeding by solution prepolymerization method.Infrared spectra(IR),Differential scanning calorimetry(DSC) and specific viscosity method were carried out to examine the structure,glass transition temperature(Tg) and molecular weight of these SMPUs.The shape memory abilities and tensile properties of the material were investigated simultaneously.The IR results showed that the SMPUs were successfully synthesized and the Tg of the samples were all above 45 ℃ according to the DSC test.All the samples can recover to its original shape completely after bending to 180°.Tensile properties were tested on the samples.The sample MDI/PBAG/BDO with the mole ratio 4/1/3 gets the best tensile strength and highest ultimate elongation.
基金Funded by Chinese Natural Science Foundation Committee(No.50673080)
文摘A series of thermoreversible konjac glucomannan gels crosslinked by organic borate were prepared. Required amount of hydrophilic SiO2 was added into the konjac glucomannan solutions before the crosslinking reaction, The gel network was formed through the crosslinking reaction between borate ions dissociated from organic borate and the cis-diol hydroxyl groups on the mannose units of polysaccharide chains. The rheological properties of the complex gels were studied by dynamic viscoelastic measurement. The gelation kinetics of the complex gels was studied and the critical getation points of the gels were exactly determined by the Winter-Chambon criterion. The effects of temperature and composite ratio on the shear storage modulus (G'), the loss modulus (G") and the sol-gel transition points were investigated.