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2019 Volume 36 Issue 6
2019, 36(6): 611-621
doi: 10.11944/j.issn.1000-0518.2019.06.190003
Abstract:
Electrospinning technology is a simple and efficient method for preparing continuous micro-nanofibers. The nanofibers are favored by the material science community because of their unique structure size and wide applications. Calixarene and its derivatives are the third generation supramolecular host compounds, which have wide applications due to their unique molecular structure, excellent ion selective recognition and adsorption property. In this review, the principle of preparing calixarene-functionalized nanofibers by electrospinning is briefly described, and the applications as adsorbents and catalyst supports are systematically discussed. In addition, the advantages of combining electrospinning and calixarene are highlighted. At last, the challenges in calixarene-functionalized nanofibers by electrospinning are discussed, and the future development direction is prospected.
Electrospinning technology is a simple and efficient method for preparing continuous micro-nanofibers. The nanofibers are favored by the material science community because of their unique structure size and wide applications. Calixarene and its derivatives are the third generation supramolecular host compounds, which have wide applications due to their unique molecular structure, excellent ion selective recognition and adsorption property. In this review, the principle of preparing calixarene-functionalized nanofibers by electrospinning is briefly described, and the applications as adsorbents and catalyst supports are systematically discussed. In addition, the advantages of combining electrospinning and calixarene are highlighted. At last, the challenges in calixarene-functionalized nanofibers by electrospinning are discussed, and the future development direction is prospected.
2019, 36(6): 622-630
doi: 10.11944/j.issn.1000-0518.2019.06.190049
Abstract:
Triblock copolymer, poly(D-lactide)-b-polydimethylsiloxane-b-poly(D-lactide)(PDLA-b-PDMS-b-PDLA), was synthesized by ring-opening polymerization of D-lactide, and then its solution was coated onto the surface of poly(L-lactide)(PLLA) in a vail filled with non-solvent vapor. During the slow deposition process, PDMS with low surface energy was introduced to the PLLA surface. Meanwhile, PDLA segments stereocomplexed with the PLLA segments on the surface. A hydrophobic layer composed of stereocomposite submicron particles was formed on the surface of PLLA through the stereocomplexation between PLLA and PDLA-b-PDMS-b-PDLA and the self-assembly of PDLA-b-PDMS-b-PDLA. The influences of polymer solution concentration, assembly temperature and solvent on the surface morphology and the hydrophobicity of PLLA surface were further studied. With the increase of the concentration of PDLA-b-PDMS-b-PDLA, the hydrophobic behavior of the surface showed a transformation from Wenzel to Cassie status, and then returned to Wenzel status. When the assembly temperature was 0℃ and a 2 g/L PDLA-b-PDMS-b-PDLA/CH2Cl2 solution was deposited on the PLLA surface, the contact angle was 151°. When the assembly temperature raised to 30℃, the surface contact angle was 144° and the rolling angle was 5°. The obtained surface morphology and hydrophobicity were also varied with solvents with different solubility and volatilization rate. In addition, the hydrophobic surface of PLLA products can be achieved by means of stereocomplexation and self-assembly. By varying the concentration of PDLA-b-PDMS-b-PDLA solutions, the surface of PLLA products would eventually assembles into a "pearl necklace" shaped bicontinuous network structure. Because the surface of PLLA and the submicron particles were all connected with stereocomplexed PLLA/PDLA chains, the hydrophobic layer exhibited good durability against knife-scratch, tape-peel and finger-wipe tests. After the knife-scratch test and the tape peel test, the contact angle of the surface of the PLLA products was only slightly reduced, and the micro-spherical appearance of the PLLA surface existed after test.
Triblock copolymer, poly(D-lactide)-b-polydimethylsiloxane-b-poly(D-lactide)(PDLA-b-PDMS-b-PDLA), was synthesized by ring-opening polymerization of D-lactide, and then its solution was coated onto the surface of poly(L-lactide)(PLLA) in a vail filled with non-solvent vapor. During the slow deposition process, PDMS with low surface energy was introduced to the PLLA surface. Meanwhile, PDLA segments stereocomplexed with the PLLA segments on the surface. A hydrophobic layer composed of stereocomposite submicron particles was formed on the surface of PLLA through the stereocomplexation between PLLA and PDLA-b-PDMS-b-PDLA and the self-assembly of PDLA-b-PDMS-b-PDLA. The influences of polymer solution concentration, assembly temperature and solvent on the surface morphology and the hydrophobicity of PLLA surface were further studied. With the increase of the concentration of PDLA-b-PDMS-b-PDLA, the hydrophobic behavior of the surface showed a transformation from Wenzel to Cassie status, and then returned to Wenzel status. When the assembly temperature was 0℃ and a 2 g/L PDLA-b-PDMS-b-PDLA/CH2Cl2 solution was deposited on the PLLA surface, the contact angle was 151°. When the assembly temperature raised to 30℃, the surface contact angle was 144° and the rolling angle was 5°. The obtained surface morphology and hydrophobicity were also varied with solvents with different solubility and volatilization rate. In addition, the hydrophobic surface of PLLA products can be achieved by means of stereocomplexation and self-assembly. By varying the concentration of PDLA-b-PDMS-b-PDLA solutions, the surface of PLLA products would eventually assembles into a "pearl necklace" shaped bicontinuous network structure. Because the surface of PLLA and the submicron particles were all connected with stereocomplexed PLLA/PDLA chains, the hydrophobic layer exhibited good durability against knife-scratch, tape-peel and finger-wipe tests. After the knife-scratch test and the tape peel test, the contact angle of the surface of the PLLA products was only slightly reduced, and the micro-spherical appearance of the PLLA surface existed after test.
2019, 36(6): 631-640
doi: 10.11944/j.issn.1000-0518.2019.06.180263
Abstract:
A series of sulfonic waterborne polyurethane hydrogels(WPUHs) was prepared by in-situ polymerization using 3-isocyanatomethyl-3, 5, 5-trimethylcyclohexyl isocyanate(IPDI), polyethylene glycol(PEG) and diethylene glycol(DEG) as raw materials, and 2, 2-dimethylol propionic acid(DMPA) and N, N-bis(2-hydroxyethyl)-2-aminoethanesulfonic acid sodium salt(BES-Na) as hydrophilic chain extenders. The structure and properties of the gels are characterized by X-ray diffractometer, thermogravimetric analyzer and electro-mechanical universal testing machine. The results show that the thermal stability of the hydrogels increases gradually with the increase of BES-Na mass fraction, and the compressive strength and compressive modulus of WPUH7 hydrogel containing 3.46% mass fraction BES-Na are 2.9 times and 3.6 times higher than those of the WPUH1 hydrogel containing 0% mass fraction BES-Na, respectively. The swelling ratio increases from 20.55 to 29.25, and the increase of BES-Na mass fraction has a significant influence on the initial process of hydrogel swelling. At the same time, the swelling ratio of WPUH7 hydrogel increases from 17.64 to 33.80 in the range of 10~45℃ and from 20.74 to 70.69 in the range of pH 2~10, indicating that hydrogels have good sensitivity to temperature and pH.
A series of sulfonic waterborne polyurethane hydrogels(WPUHs) was prepared by in-situ polymerization using 3-isocyanatomethyl-3, 5, 5-trimethylcyclohexyl isocyanate(IPDI), polyethylene glycol(PEG) and diethylene glycol(DEG) as raw materials, and 2, 2-dimethylol propionic acid(DMPA) and N, N-bis(2-hydroxyethyl)-2-aminoethanesulfonic acid sodium salt(BES-Na) as hydrophilic chain extenders. The structure and properties of the gels are characterized by X-ray diffractometer, thermogravimetric analyzer and electro-mechanical universal testing machine. The results show that the thermal stability of the hydrogels increases gradually with the increase of BES-Na mass fraction, and the compressive strength and compressive modulus of WPUH7 hydrogel containing 3.46% mass fraction BES-Na are 2.9 times and 3.6 times higher than those of the WPUH1 hydrogel containing 0% mass fraction BES-Na, respectively. The swelling ratio increases from 20.55 to 29.25, and the increase of BES-Na mass fraction has a significant influence on the initial process of hydrogel swelling. At the same time, the swelling ratio of WPUH7 hydrogel increases from 17.64 to 33.80 in the range of 10~45℃ and from 20.74 to 70.69 in the range of pH 2~10, indicating that hydrogels have good sensitivity to temperature and pH.
2019, 36(6): 641-648
doi: 10.11944/j.issn.1000-0518.2019.06.180403
Abstract:
Heparin has been used as anti-thrombotic agents clinically. In this work, the copolymer based on hydrophilic heparin and hydrophobic deoxycholic acid(hep-DOCA, HD) was synthesized. Indometacin(IDM)-loaded HD micelles were prepared through aqueous self-assembly to enhance the anti-thrombotic capability of micelles synergistically and characterized by dynamic light scattering, Zeta potential and transmission electron microscopry(TEM). When the drug content of the nanomicelles was 0.0913 g/L, the concentration of the drug-loaded nanomicelle was 0.4 g/L, and the cell survival rate and hemolysis rate were 92.81% and 0.83%, indicating that the drug-loaded nanomicelles had good biocompatibility. The whole blood coagulation indexes of heparin sodium, hep-DOCA and HD-IDM were 86.48%, 77.47% and 89.53%, respectively. The whole blood coagulation time was 927, 837 and 965 s, respectively. The thrombus mass produced in the thrombus clotting experiment was 0.11, 0.20 and 0.07 g, respectively, which confirmed that the drug-loaded nanomicelles had excellent anticoagulant effect.
Heparin has been used as anti-thrombotic agents clinically. In this work, the copolymer based on hydrophilic heparin and hydrophobic deoxycholic acid(hep-DOCA, HD) was synthesized. Indometacin(IDM)-loaded HD micelles were prepared through aqueous self-assembly to enhance the anti-thrombotic capability of micelles synergistically and characterized by dynamic light scattering, Zeta potential and transmission electron microscopry(TEM). When the drug content of the nanomicelles was 0.0913 g/L, the concentration of the drug-loaded nanomicelle was 0.4 g/L, and the cell survival rate and hemolysis rate were 92.81% and 0.83%, indicating that the drug-loaded nanomicelles had good biocompatibility. The whole blood coagulation indexes of heparin sodium, hep-DOCA and HD-IDM were 86.48%, 77.47% and 89.53%, respectively. The whole blood coagulation time was 927, 837 and 965 s, respectively. The thrombus mass produced in the thrombus clotting experiment was 0.11, 0.20 and 0.07 g, respectively, which confirmed that the drug-loaded nanomicelles had excellent anticoagulant effect.
2019, 36(6): 649-657
doi: 10.11944/j.issn.1000-0518.2019.06.180339
Abstract:
The effect of the mass ratio and composition of melamine polyphosphate(MPP)/pentaerythritol(PER) in intumescent flame retardants(IFRs), synergist group MgO/EG/SiO2 of which composition with m(MgO):m(expandable graphite, EG):m(SiO2)=1:5:5, and the silane coupling agent KH550 on the flame retardancy of polypropylene-based wood-plastic composites(WPC) were studied by means of limiting oxygen index(LOI), linear burning rate(LBR), thermogravimetric analysis and cone calorimetry. The results show that when m(MPP):m(PER)=23:2 in IFRs(code IFRs-M1) and its mass fraction is 25%, the flame retardant performance is the best, and LOI and LBR of the intumescent flame retardant composite WPC/IFRs-M1 are 27.1% and 3.89 mm/min, respectively, which are 48.1% higher and 89.79% lower than those of the unadded WPC. Compared with the unadded WPC, the heat release rate and total heat release during combustion decrease by 76.2% and 50.1%, the carbon residue rate at 600℃ increases by 498.3%, the total smoke emission reduces by 6.9%, and the release of CO2 drops by 65.4%. It also indicates that both the synergist group and KH550 surface treatment can further improve the flame retardant properties of WPC/IFRs-M1, and both have good flame retardant synergistic effect on IFRs-M1. Compared with WPC/IFRs-M1, LOI of WPC/IFRs-M1/MgO/EG/SiO2/KH550 with both flame retardant means mentioned above is enhanced by 3.7%, and its LBR declines by 20.3%. At the same time, its thermal stability significantly improves, the thermal weight loss goes down, and its heat release rate and total heat release during combustion reduce by 36.5% and 37.6%, respectively. Its carbon residue rate at 600℃ increases by 84.02%, the total smoke release reduces by 57.5%, and the amount of CO2 release reduces by 33.33%, indicating a better synergistic effect.
The effect of the mass ratio and composition of melamine polyphosphate(MPP)/pentaerythritol(PER) in intumescent flame retardants(IFRs), synergist group MgO/EG/SiO2 of which composition with m(MgO):m(expandable graphite, EG):m(SiO2)=1:5:5, and the silane coupling agent KH550 on the flame retardancy of polypropylene-based wood-plastic composites(WPC) were studied by means of limiting oxygen index(LOI), linear burning rate(LBR), thermogravimetric analysis and cone calorimetry. The results show that when m(MPP):m(PER)=23:2 in IFRs(code IFRs-M1) and its mass fraction is 25%, the flame retardant performance is the best, and LOI and LBR of the intumescent flame retardant composite WPC/IFRs-M1 are 27.1% and 3.89 mm/min, respectively, which are 48.1% higher and 89.79% lower than those of the unadded WPC. Compared with the unadded WPC, the heat release rate and total heat release during combustion decrease by 76.2% and 50.1%, the carbon residue rate at 600℃ increases by 498.3%, the total smoke emission reduces by 6.9%, and the release of CO2 drops by 65.4%. It also indicates that both the synergist group and KH550 surface treatment can further improve the flame retardant properties of WPC/IFRs-M1, and both have good flame retardant synergistic effect on IFRs-M1. Compared with WPC/IFRs-M1, LOI of WPC/IFRs-M1/MgO/EG/SiO2/KH550 with both flame retardant means mentioned above is enhanced by 3.7%, and its LBR declines by 20.3%. At the same time, its thermal stability significantly improves, the thermal weight loss goes down, and its heat release rate and total heat release during combustion reduce by 36.5% and 37.6%, respectively. Its carbon residue rate at 600℃ increases by 84.02%, the total smoke release reduces by 57.5%, and the amount of CO2 release reduces by 33.33%, indicating a better synergistic effect.
2019, 36(6): 658-663
doi: 10.11944/j.issn.1000-0518.2019.06.180352
Abstract:
A novel diketone anhydride polyimide was synthesized by introducing p-phenylenediamine(PPD) to 4, 4'-terephthaloyldiphthalic anhydride through the traditional two-step method in dimethylacetamide(DMAc). The properties of the polyimide were characterized by Fourier transform infrared spectrometer(FT-IR), wide-angle X-ray diffraction(WAXD), differential scanning calorimetric(DSC), dynamic thermomechanical analyzer(DMA), thermal gravimetric analysis(TGA), tensile test and ultraviolet-visible spectrophotometry(UV-Vis). The relationship between different thermal imidization temperature and the properties of the diketone polyimide was studied. The results showed that PAA formed the imide ring structure completely at 320℃. The polyimide had good film-forming performance and partially ordered aggregate structure. The polyimide had excellent thermal properties:the glass transition temperature(Tg) was 298℃ and the thermal decomposition temperature(T5%) was 523℃. The film had a tensile strength of 130 MPa and tensile modulus of 5.77 GPa at 320℃. The cutoff wavelength of the film was 375 nm and the film had good transmittance in visible region.
A novel diketone anhydride polyimide was synthesized by introducing p-phenylenediamine(PPD) to 4, 4'-terephthaloyldiphthalic anhydride through the traditional two-step method in dimethylacetamide(DMAc). The properties of the polyimide were characterized by Fourier transform infrared spectrometer(FT-IR), wide-angle X-ray diffraction(WAXD), differential scanning calorimetric(DSC), dynamic thermomechanical analyzer(DMA), thermal gravimetric analysis(TGA), tensile test and ultraviolet-visible spectrophotometry(UV-Vis). The relationship between different thermal imidization temperature and the properties of the diketone polyimide was studied. The results showed that PAA formed the imide ring structure completely at 320℃. The polyimide had good film-forming performance and partially ordered aggregate structure. The polyimide had excellent thermal properties:the glass transition temperature(Tg) was 298℃ and the thermal decomposition temperature(T5%) was 523℃. The film had a tensile strength of 130 MPa and tensile modulus of 5.77 GPa at 320℃. The cutoff wavelength of the film was 375 nm and the film had good transmittance in visible region.
2019, 36(6): 664-670
doi: 10.11944/j.issn.1000-0518.2019.06.180338
Abstract:
A novel and efficient protocol towards (E)-β-vinyl sulfone derivatives by tetrabutylammonium Iodide(TBAI)/K2S2O8 mediated denitrative sulfonylation of readily prepared β-nitrostyrenes and economical sulfonylhydrazides was described. The corresponding (E)-β-vinyl sulfone compounds were obtained in moderate to good yields. Compared with reported methods, the present strategy features metal-free, acid and base-free.
A novel and efficient protocol towards (E)-β-vinyl sulfone derivatives by tetrabutylammonium Iodide(TBAI)/K2S2O8 mediated denitrative sulfonylation of readily prepared β-nitrostyrenes and economical sulfonylhydrazides was described. The corresponding (E)-β-vinyl sulfone compounds were obtained in moderate to good yields. Compared with reported methods, the present strategy features metal-free, acid and base-free.
2019, 36(6): 671-676
doi: 10.11944/j.issn.1000-0518.2019.06.180355
Abstract:
To further develop an efficient structural modification strategy for the conversion of the antibacterial activity of fluoroquinolone into an antitumor activity, fused heterocyclic with unsaturated ketone was designed as the bioisosteric replacement of the C-3 carboxylic acid group. Accordingly, twelve novel C-3 thiazolotriazole unsaturated ketones(6a-6l) were synthesized from levofloxacin 1. The in vitro antitumor activity of the title compounds exhibited more significant potency than that of levofloxacin. The compounds with fluorophenyl or o-methoxyphenyl displayed comparable activity to doxorubicin. Thus, a fused heterocyclic unsaturated ketone skeleton as an isostere of the C-3 carboxylic acid group appears to be an alternative route for further design of lead antitumor fluoroquinolone.
To further develop an efficient structural modification strategy for the conversion of the antibacterial activity of fluoroquinolone into an antitumor activity, fused heterocyclic with unsaturated ketone was designed as the bioisosteric replacement of the C-3 carboxylic acid group. Accordingly, twelve novel C-3 thiazolotriazole unsaturated ketones(6a-6l) were synthesized from levofloxacin 1. The in vitro antitumor activity of the title compounds exhibited more significant potency than that of levofloxacin. The compounds with fluorophenyl or o-methoxyphenyl displayed comparable activity to doxorubicin. Thus, a fused heterocyclic unsaturated ketone skeleton as an isostere of the C-3 carboxylic acid group appears to be an alternative route for further design of lead antitumor fluoroquinolone.
2019, 36(6): 677-682
doi: 10.11944/j.issn.1000-0518.2019.06.180364
Abstract:
A natural antibacterial cyclic peptide thermoactinoamide A was synthesized by solid-liquid phase two-step method. First, based on fluorenylmethoxycarbonyl(Fmoc) solid phase synthesis, the linear peptide was obtained in 84% yield by optimizing the addition of N, N'-diisopropylethylamine(DIPEA). Then the linear peptide was converted to thermoactinoamide A in 51% yield(43% yield total) through optimizing the cyclization conditions. Antibacterial activity test results show that minimum inhibitory concentration of cyclic thermoactinoamide A for Staphylococcus aureus is 32 μg/mL. In summary, an effectively synthetic strategy was developed for further applications of cyclic peptide thermoactinoamide A on analyzing the structure-activity relationship and improving the bioactivity.
A natural antibacterial cyclic peptide thermoactinoamide A was synthesized by solid-liquid phase two-step method. First, based on fluorenylmethoxycarbonyl(Fmoc) solid phase synthesis, the linear peptide was obtained in 84% yield by optimizing the addition of N, N'-diisopropylethylamine(DIPEA). Then the linear peptide was converted to thermoactinoamide A in 51% yield(43% yield total) through optimizing the cyclization conditions. Antibacterial activity test results show that minimum inhibitory concentration of cyclic thermoactinoamide A for Staphylococcus aureus is 32 μg/mL. In summary, an effectively synthetic strategy was developed for further applications of cyclic peptide thermoactinoamide A on analyzing the structure-activity relationship and improving the bioactivity.
2019, 36(6): 683-689
doi: 10.11944/j.issn.1000-0518.2019.06.180327
Abstract:
CeCl3·7H2O, CaCl2·2H2O and C2H2O4·2H2O were used as raw materials to prepare Ca2+-doped cerium oxalate by the coprecipitation method. The Ca2+-doped cerium oxalate was calcined to obtain Ca2+-doped cerium oxide precursor. Ca2+-doped γ-Ce2S3 was achieved by vulcanizing precursors in an Ar atmosphere using CS2 as the sulfur source. Pigments were characterized by X-ray diffraction(XRD), energy dispersive spectrometer(EDS), color analyzer, UV-Vis spectrophotometer and thermogravimetric analysis-differential thermal analysis(TG-DTA). The results show that Ca2+-doping can lower the synthesis temperature and improve the thermal stability of pigments in air. When the ratio of n(Ca2+):n(Ce3+) ≥ 0.16, pure phase γ-Ce2S3 can be obtained by vulcanizing at 900℃ for 150 min. The synthesis temperature of doped γ-Ce2S3 decrease by 300℃ compared with undoped γ-Ce2S3. When the n(Ca2+):n(Ce3+) is 0.64, the oxidation exothermic peak of Ca2+-doped γ-Ce2S3 increases from 490.6 to 541.0 ℃.
CeCl3·7H2O, CaCl2·2H2O and C2H2O4·2H2O were used as raw materials to prepare Ca2+-doped cerium oxalate by the coprecipitation method. The Ca2+-doped cerium oxalate was calcined to obtain Ca2+-doped cerium oxide precursor. Ca2+-doped γ-Ce2S3 was achieved by vulcanizing precursors in an Ar atmosphere using CS2 as the sulfur source. Pigments were characterized by X-ray diffraction(XRD), energy dispersive spectrometer(EDS), color analyzer, UV-Vis spectrophotometer and thermogravimetric analysis-differential thermal analysis(TG-DTA). The results show that Ca2+-doping can lower the synthesis temperature and improve the thermal stability of pigments in air. When the ratio of n(Ca2+):n(Ce3+) ≥ 0.16, pure phase γ-Ce2S3 can be obtained by vulcanizing at 900℃ for 150 min. The synthesis temperature of doped γ-Ce2S3 decrease by 300℃ compared with undoped γ-Ce2S3. When the n(Ca2+):n(Ce3+) is 0.64, the oxidation exothermic peak of Ca2+-doped γ-Ce2S3 increases from 490.6 to 541.0 ℃.
2019, 36(6): 690-697
doi: 10.11944/j.issn.1000-0518.2019.06.180349
Abstract:
Nematic liquid crystals(NLC) materials are widely used in liquid crystal display. However, due to the presence of impurities, the driving voltage of the liquid crystal becomes large, which results in the increasing energy consumption. In order to decrease the threshold voltage and saturation voltage, nanoparticles are usually added to liquid crystal to improve the electro-optical performance. In this paper, rough and smooth cubic ferric oxide nanoparticles with uniform shape and size of~550 nm were prepared by a hydrothermal method. NLC E7 was doped with cubic Fe2O3 nanoparticles in different doping mass percent. Compared with the smooth Fe2O3/E7 composite and NLC E7, the rough Fe2O3/E7 composite has superior electro-optical properties. When the doping mass percent is 0.4%, the electro-optical properties reach the best. The threshold voltage and saturation voltage decrease by 9.9% and 11.6%, respectively, the contrast ratio increases by 80%, and the response time decreases to 6.0 ms. The superior electro-optical properties can be attributed to the sufficient surface area and more charge on the surface of rough cubic Fe2O3, which is beneficial to absorb the impurity ions in the NLC system and weaken the shielding effect of impurity ions, thus improving the electro-optical properties.
Nematic liquid crystals(NLC) materials are widely used in liquid crystal display. However, due to the presence of impurities, the driving voltage of the liquid crystal becomes large, which results in the increasing energy consumption. In order to decrease the threshold voltage and saturation voltage, nanoparticles are usually added to liquid crystal to improve the electro-optical performance. In this paper, rough and smooth cubic ferric oxide nanoparticles with uniform shape and size of~550 nm were prepared by a hydrothermal method. NLC E7 was doped with cubic Fe2O3 nanoparticles in different doping mass percent. Compared with the smooth Fe2O3/E7 composite and NLC E7, the rough Fe2O3/E7 composite has superior electro-optical properties. When the doping mass percent is 0.4%, the electro-optical properties reach the best. The threshold voltage and saturation voltage decrease by 9.9% and 11.6%, respectively, the contrast ratio increases by 80%, and the response time decreases to 6.0 ms. The superior electro-optical properties can be attributed to the sufficient surface area and more charge on the surface of rough cubic Fe2O3, which is beneficial to absorb the impurity ions in the NLC system and weaken the shielding effect of impurity ions, thus improving the electro-optical properties.
2019, 36(6): 698-703
doi: 10.11944/j.issn.1000-0518.2019.06.180328
Abstract:
A series of NiO/Mn3O4 monolithic catalysts with different NiO contents was prepared by ball-milling of Ni(NO3)2·6H2O, Mn3O4 and pseudo boehmite precusors via subsequent impregnation with cordierite, followed by calcination. These catalysts were tested for ozone decomposition. It was found that the 30NiO/Mn3O4(mass fraction of NiO in total mass is 30%) catalyst has the highest activity at a space velocity of 20000 h-1, and leads to 98% conversion of ozone, while the catalyst remains stable. When the space velocity is increased to 40000 h-1, the 50NiO/Mn3O4(mass fraction of NiO in total mass is 50%) catalyst gives the highest activity, with a ozone conversion at about 90%. But the catalyst suffers deactivation. Characterizations by X-ray diffraction(XRD), TPR, XPS and BET reveal that the presence of Mn3O4 in the NiO increases the specific surface area of the catalyst, and electronic interaction between Mn3O4 and NiO. Meanwhile, the co-presence of Mn3O4 and NiO in the catalyst results in facile reduction of these oxides. This synergy is believed to be responsible for the enhanced catalytic performance.
A series of NiO/Mn3O4 monolithic catalysts with different NiO contents was prepared by ball-milling of Ni(NO3)2·6H2O, Mn3O4 and pseudo boehmite precusors via subsequent impregnation with cordierite, followed by calcination. These catalysts were tested for ozone decomposition. It was found that the 30NiO/Mn3O4(mass fraction of NiO in total mass is 30%) catalyst has the highest activity at a space velocity of 20000 h-1, and leads to 98% conversion of ozone, while the catalyst remains stable. When the space velocity is increased to 40000 h-1, the 50NiO/Mn3O4(mass fraction of NiO in total mass is 50%) catalyst gives the highest activity, with a ozone conversion at about 90%. But the catalyst suffers deactivation. Characterizations by X-ray diffraction(XRD), TPR, XPS and BET reveal that the presence of Mn3O4 in the NiO increases the specific surface area of the catalyst, and electronic interaction between Mn3O4 and NiO. Meanwhile, the co-presence of Mn3O4 and NiO in the catalyst results in facile reduction of these oxides. This synergy is believed to be responsible for the enhanced catalytic performance.
2019, 36(6): 704-710
doi: 10.11944/j.issn.1000-0518.2019.06.180313
Abstract:
An all-solid-state Ca2+ ion selective electrode(Ca2+-ISE) was prepared with carbon nanotube(CNT)/Ag/MoS2 as the ion-to-electron transducer and tripodal compound as the calcium ionophore. The stability, slope, response range, selectivity coefficient, etc. of the electrode were investigated. It is revealed that the electrode exhibits a 28.1 mV/decade Nernst slope in the range of 1×10-6~1×10-1 mol/L Ca2+ concentration. The transducer is helpful in enlarging the linear response range of the Ca2+ concentration, shortening the potential balance time and reducing the difference of the Nernst slope. All of these results are important for long-term online detection of calcium ions for the solid electrode.
An all-solid-state Ca2+ ion selective electrode(Ca2+-ISE) was prepared with carbon nanotube(CNT)/Ag/MoS2 as the ion-to-electron transducer and tripodal compound as the calcium ionophore. The stability, slope, response range, selectivity coefficient, etc. of the electrode were investigated. It is revealed that the electrode exhibits a 28.1 mV/decade Nernst slope in the range of 1×10-6~1×10-1 mol/L Ca2+ concentration. The transducer is helpful in enlarging the linear response range of the Ca2+ concentration, shortening the potential balance time and reducing the difference of the Nernst slope. All of these results are important for long-term online detection of calcium ions for the solid electrode.
2019, 36(6): 711-716
doi: 10.11944/j.issn.1000-0518.2019.06.180320
Abstract:
A micro-luteolin carbon fiber acidity microelectrode(Lu/CFME) was made with luteolin as a pH sensitive substance, carbon fiber as conductive matrix and solid paraffin as a binder. An all solid state acidity microelectrode set was combinated by Lu/CFME as working electrode, a self-made conductive gel type all-solid micro Ag/AgCl as reference electrode and a platinum wire microelectrode as auxiliary electrode. The response of the electrode set to the effective acidity was studied in the solution of phosphate buffer solution at pH 2.00~10.00 by cyclic voltammetry. The results show that there is a pair of reversible redox peaks on the cyclic voltammetry curve. Their peak potentials(Epa) were all linear with pH. Based on this, a method for determining the acidity of solution was established by square wave voltammetry, and the linear regression equation for peak potential of oxidation peak and pH is Epa(V)=-0.0567pH+0.603(r=0.999). The electrode set is micro, non-toxic and anti-interference. It is applied to acidity measurement of trace saliva and sweat on the skin surface, and satisfactory results have been obtained. Therefore, this result provides a technical basis for real-time, in-vivo detection of body fluids.
A micro-luteolin carbon fiber acidity microelectrode(Lu/CFME) was made with luteolin as a pH sensitive substance, carbon fiber as conductive matrix and solid paraffin as a binder. An all solid state acidity microelectrode set was combinated by Lu/CFME as working electrode, a self-made conductive gel type all-solid micro Ag/AgCl as reference electrode and a platinum wire microelectrode as auxiliary electrode. The response of the electrode set to the effective acidity was studied in the solution of phosphate buffer solution at pH 2.00~10.00 by cyclic voltammetry. The results show that there is a pair of reversible redox peaks on the cyclic voltammetry curve. Their peak potentials(Epa) were all linear with pH. Based on this, a method for determining the acidity of solution was established by square wave voltammetry, and the linear regression equation for peak potential of oxidation peak and pH is Epa(V)=-0.0567pH+0.603(r=0.999). The electrode set is micro, non-toxic and anti-interference. It is applied to acidity measurement of trace saliva and sweat on the skin surface, and satisfactory results have been obtained. Therefore, this result provides a technical basis for real-time, in-vivo detection of body fluids.
2019, 36(6): 717-725
doi: 10.11944/j.issn.1000-0518.2019.06.180302
Abstract:
Montmorillonite surface was pickled, activated with silane coupling agent, bonded with benzoyl isothiocyanate to give a solid phase extraction(SPE) material. The structure and the morphology of this modified montmorillonite were characterized by infrared spectroscopy, scanning electron microscopy, X-ray photoelectron spectroscopy. Its adsorption performance toward As3+, Bi3+, Cu2+, Sb3+, Sn2+ and Pb2+ in water was also investigated, and the optimal solid-phase extraction conditions were determined. The adsorption capacities of this modified montmorillonite solid phase extraction packing material toward As3+, Bi3+, Cu2+, Sb3+, Sn2+ and Pb2+ were 10.83, 11.92, 12.67, 10.43, 10.01 and 10.54 mg/g, respectively. The contents of heavy metal ions in the samples were determined by SPE and ion couple plasma-mass spectrometry. The detection limits were 0.024, 0.013, 0.075, 0.037 and 0.011 μg/L, respectively.
Montmorillonite surface was pickled, activated with silane coupling agent, bonded with benzoyl isothiocyanate to give a solid phase extraction(SPE) material. The structure and the morphology of this modified montmorillonite were characterized by infrared spectroscopy, scanning electron microscopy, X-ray photoelectron spectroscopy. Its adsorption performance toward As3+, Bi3+, Cu2+, Sb3+, Sn2+ and Pb2+ in water was also investigated, and the optimal solid-phase extraction conditions were determined. The adsorption capacities of this modified montmorillonite solid phase extraction packing material toward As3+, Bi3+, Cu2+, Sb3+, Sn2+ and Pb2+ were 10.83, 11.92, 12.67, 10.43, 10.01 and 10.54 mg/g, respectively. The contents of heavy metal ions in the samples were determined by SPE and ion couple plasma-mass spectrometry. The detection limits were 0.024, 0.013, 0.075, 0.037 and 0.011 μg/L, respectively.
Preparation and Chromatographic Evaluation of a L-Isoleucine-Bonded Chromatographic Stationary Phase
2019, 36(6): 726-732
doi: 10.11944/j.issn.1000-0518.2019.06.180356
Abstract:
L-Isoleucine-bonded silica stationary phase was prepared starting from L-isoleucine and 3-isocyanatopropyltriethoxysilane, and further reaction between the resulting L-isoleucine functionalized silane coupling agents and activated silica. The result of 1H NMR spectroscopy showed that the expected L-isoleucine functionalized silane was successfully synthesized. The successful grafting was further confirmed by elemental analysis. The synthesized stationary phase was slurry-packed into stainless steel columns(150 mm×4.6 mm). A set of typical polar compounds were employed to evaluate the chromatographic behaviors on the stationary phase in hydrophilic interaction liguid chromatography(HILIC) mode. Increased retention factors were observed for these compounds with the increase of acetonitrile(ACN) content in the mobile phase, demonstrating a typical HILIC retention characteristics. Additionally, the effect of various parameters, such as ACN content, pH values and ionic strength of the mobile phase on the retention of the tested solutes were investigated. Under optimized conditions, 5 basic compounds, 6 water-soluble vitamins and 8 nucleosides were successfully separated within 8 min, 18 min and 25 min, respectively, by isocratic elution. The resulting separation chromatogram exhibits remarkable chromatographic performance, demonstrating the excellent application potential of the L-isoleucine-bonded silica stationary phase in the separation of polar compounds.
L-Isoleucine-bonded silica stationary phase was prepared starting from L-isoleucine and 3-isocyanatopropyltriethoxysilane, and further reaction between the resulting L-isoleucine functionalized silane coupling agents and activated silica. The result of 1H NMR spectroscopy showed that the expected L-isoleucine functionalized silane was successfully synthesized. The successful grafting was further confirmed by elemental analysis. The synthesized stationary phase was slurry-packed into stainless steel columns(150 mm×4.6 mm). A set of typical polar compounds were employed to evaluate the chromatographic behaviors on the stationary phase in hydrophilic interaction liguid chromatography(HILIC) mode. Increased retention factors were observed for these compounds with the increase of acetonitrile(ACN) content in the mobile phase, demonstrating a typical HILIC retention characteristics. Additionally, the effect of various parameters, such as ACN content, pH values and ionic strength of the mobile phase on the retention of the tested solutes were investigated. Under optimized conditions, 5 basic compounds, 6 water-soluble vitamins and 8 nucleosides were successfully separated within 8 min, 18 min and 25 min, respectively, by isocratic elution. The resulting separation chromatogram exhibits remarkable chromatographic performance, demonstrating the excellent application potential of the L-isoleucine-bonded silica stationary phase in the separation of polar compounds.
