The palladium complex of the molecular complex of poly(4 vinylpyridine) with acetic acid(PVP/ HAc Pd) was prepared. Its catalytic activity for the hydrogenation of nitrobenzene was found much higher than that of the c...The palladium complex of the molecular complex of poly(4 vinylpyridine) with acetic acid(PVP/ HAc Pd) was prepared. Its catalytic activity for the hydrogenation of nitrobenzene was found much higher than that of the corresponding palladium complex of poly(4 vinylpyridine). In the presence of a strong inorganic alkali, especially potassium hydroxide, the catalytic activity is greatly improved. The suitable hydrogenation condition for PVP/HAc Pd is to use 0 1 mol/L ethanol solution of potassium hydroxide as the hydrogenation medium and the hydrogenation is carried out at 45 ℃.展开更多
The catalytic activity of poly（styrene-acrylic acid） （PSAA） supported neodymium chloride （NdCl3） complex for the copolymerization of styrene and 4-Vinylpyridine was studied. The influence of various factors, suc...The catalytic activity of poly（styrene-acrylic acid） （PSAA） supported neodymium chloride （NdCl3） complex for the copolymerization of styrene and 4-Vinylpyridine was studied. The influence of various factors, such as Al/Nd molar ratio, reaction time, macromolecular carder （PSAA）, and ratio of styrene to 4-vinypyridine （g/g）, on the copolymerization yield of styrene and 4-Vinylpyridine was investigated. The results showed that the copolymerization of polar monomers with olefins occurred efficiently and the catalytic activity of polymer-supported catalyst was higher than that of the similar small molecular catalysts. The activity of PSAA.Nd complex increased with in- creasing Al/Nd molar ratios and decreased with increasing polymerization time. The highest activity of PSAA＇Nd was observed at 120 min, and the highest yield was found at the ratio of styrene to 4-vinylpyridine of 4：2. DSC analysis presented that the resulted polymer had only one glass transition temperature, and showed very good thermal stability.展开更多
Polyethylene (PE) grafting 4-vinylpyridine copolymers has been produced as powders of different rushes by theirradiation method. After treatment with methylaluminoxane (MAO), the copolymers were used as supports for C...Polyethylene (PE) grafting 4-vinylpyridine copolymers has been produced as powders of different rushes by theirradiation method. After treatment with methylaluminoxane (MAO), the copolymers were used as supports for Cp_2ZrCl_2catalyst Results of X-ray photoelectron spectroscopy, Fourier transforms infrared spectroscopy, ultraviolet spectroscopy andscanning electron microscope measurements show that the catalytic sites have been linked through MAO on the PE-graft-4-vinylpyridine (PEVP). The percentages of grafting 4-vinylpyridine and supported Cp_2ZrCl_2 depend on the size ofpolyethylene powder. The smaller the polyethylene powder, the more percent of 4-vinylpyridine groups and Cp_2ZrCl_2 existon the polyethylene chains, and the PEVP-supported catalyst has a relatively high activity for ethylene polymerization.展开更多
Polymerization of 4-vinylpyridine by complex catalyst of neodymium chloride was studied. The influence of Al/Nd (molar ratio), concentration of catalyst, reaction time and temperature on polymerization of 4-vinylpyrid...Polymerization of 4-vinylpyridine by complex catalyst of neodymium chloride was studied. The influence of Al/Nd (molar ratio), concentration of catalyst, reaction time and temperature on polymerization of 4-vinylpyridine was investigated. The results show that different kinds of ligand in the rare earth complex have an effect on the catalytic activity of the complex. The catalytic activity of the rare earth complex is higher than that of simple rare earth chloride. The catalytic activity of polymer-supported catalyst is higher than those of the similar small molecular system.展开更多
Poly（4-vinylpyridine）（P4-VP） nanofiber and fluoresent poly（4-vinylpyridine）/porphyrin（P4-VP/TPPA） nanofiber were respectively prepared by electrospinning. The effect of the concentration of P4-VP/dimethylforma...Poly（4-vinylpyridine）（P4-VP） nanofiber and fluoresent poly（4-vinylpyridine）/porphyrin（P4-VP/TPPA） nanofiber were respectively prepared by electrospinning. The effect of the concentration of P4-VP/dimethylformamide （DMF） electrospinning solutions on the morphology of P4-VP nanofiber was investigated and it was found that the average diameter of the nanofiber of P4-VP/DMF increased with the increase of the concentration of the spinning solution. After the addition of TPPA to the P4-VP/DMF spinning solution, the diameter of P4-VP/TPPA nanofiber became even due to the increase of the conductivity of the P4-VP/DMF-TPPA solution. The photoluminescent（PL） spectral analysis indicates that the emission peak position of P4-VP/TPPA nanofiber is almost the same as that of pure TPPA at about 650 nm without peak shift, and when it was stored for 20 days, the emission peak of P4-VP/TPPA nanofiber is also at 650 nm, indicating that the fluorescent property of P4-VP/TPPA nanofiber is stable. Fourier-transform iufrared（FTIR） spectrum confirms the chemical composition of the resulting P4-VP/TPPA composite nanofiber.展开更多
Poly(styrene-co-4-vinylpyridine)-neodymium complexes(NdCl_3·PS4VPY)with variouscontents of the functional group and neodymium have been prepared and characterized.Theinfrared and X-ray photoelectron spectra indic...Poly(styrene-co-4-vinylpyridine)-neodymium complexes(NdCl_3·PS4VPY)with variouscontents of the functional group and neodymium have been prepared and characterized.Theinfrared and X-ray photoelectron spectra indicate that uncoordinated 4-vinylpyridine(4VPY)unitsremain in the NdCl_3·PS4VPY complexes.The catalytic behaviour of NdCl_3·PS4VPY was described briefly.展开更多
The catalytic activity of poly（styrene-cryli- caeid） （PSAA） supported neodymium chloride （NdCl3） complex for the copolymerization of styrene and 4-vinylpyridine was studied. The influence of various factors, suc...The catalytic activity of poly（styrene-cryli- caeid） （PSAA） supported neodymium chloride （NdCl3） complex for the copolymerization of styrene and 4-vinylpyridine was studied. The influence of various factors, such as Al/Nd molar ratio, reaction time, and ratio of styrene to 4-vinypyridine （g· g^-1 ）, on copolymerization of styrene and 4-Vinylpridine was investigated. The results show that the copolymerization of polar monomers with olefins occurs efficiently. The catalytic activity of polymer-supported catalyst is higher than that of the similar small molecule catalysts. The activity of PSAA· Nd complex increases with increasing Al/Nd ratios and decreases with increasing polymerization time, the highest activity of PSAA· Nd is observed at 120 min. High yield is found at the ratio of styrene to 4-vinylpyridine is 4：2. The resulted polymer shows very good thermal stability.展开更多
In the UV-Vis spectra of pure light-scattering systems, there is an exponential relationship between absorbance and wavelength （A = Kλ^-n）. Here, the exponent n is named as flocculation-coagulation parameter. In th...In the UV-Vis spectra of pure light-scattering systems, there is an exponential relationship between absorbance and wavelength （A = Kλ^-n）. Here, the exponent n is named as flocculation-coagulation parameter. In the present paper, the effects of different additives on the stability of poly（N,N＇-methylenebisacrylamide-co-4-vinylpyridine） （poly（Bis-co-4-VP）） microgel dispersion were studied in detail via this parameter. The results showed that the stability of the dispersion mainly comes from the ionization of pyridine groups, making the microgel positively charged on its surface. This was confirmed by the measurement of Zeta potential and the result of conductometric titration. The result of fluorescence analysis indicated that the hydrophobicity in the microgels is enhanced with the increase in total 4-VP unit content.展开更多
An facile and efficient protocol for the synthesis of 13‐aryl‐indeno[1,2‐b]naphtha[1,2‐e]pyran‐ 12(13H)‐ ones has been developed that proceeds via the one‐pot three‐component sequential reaction of an aromatic...An facile and efficient protocol for the synthesis of 13‐aryl‐indeno[1,2‐b]naphtha[1,2‐e]pyran‐ 12(13H)‐ ones has been developed that proceeds via the one‐pot three‐component sequential reaction of an aromatic aldehyde with β‐naphthol and 2H‐indene‐1,3‐dione under solvent‐free conditions in the presence of a poly(4‐vinylpyridinium)hydrogen sulfate(P(4‐VPH)HSO4) catalyst. The catalyst can be reused several times, making this procedure facile, practical, and sustainable. The simple experimental procedure, solvent‐free reaction conditions, use of an inexpensive catalyst, short react time, and excellent yields are some of the major advantages of this methodology.展开更多
With concerns in energy crisis and global warming, researchers are actively investigating alternative energy renewable solutions. Among the various methods, piezoelectric transduction stands out due to its impressive ...With concerns in energy crisis and global warming, researchers are actively investigating alternative energy renewable solutions. Among the various methods, piezoelectric transduction stands out due to its impressive electromechanical coupling factor and coefficient. As a result, piezoelectric energy harvesting has garnered significant attention from the scientific community. In this study, we explored methods to enhance the piezoelectric properties of polyvinylidene fluoride (PVDF) through two distinct approaches. The first approach involved applying external high voltages at various stages during the mixture reaction. The goal was to determine whether this voltage application could alter or enhance PVDF’s piezoelectric conformation by improving the alignment of polarized dipoles. In the second part of our study, we investigated the effects of incorporating various nanostructures (including Iron Oxide, Magnesium Oxide, and Zinc Oxide) into PVDF. To analyze changes in PVDF’s crystalline structure, we utilized Fourier Transform Infrared Spectroscopy (FTIR) and X-ray Diffraction (XRD) techniques. Additionally, we measured the electric polarization of samples using a Precision LC Meter and examined the morphology of nanofibers through Scanning Electron Microscopy (SEM).展开更多
基金Supported by the Outstanding Youngs Science Foudation of Henan Province(1999)
文摘The palladium complex of the molecular complex of poly(4 vinylpyridine) with acetic acid(PVP/ HAc Pd) was prepared. Its catalytic activity for the hydrogenation of nitrobenzene was found much higher than that of the corresponding palladium complex of poly(4 vinylpyridine). In the presence of a strong inorganic alkali, especially potassium hydroxide, the catalytic activity is greatly improved. The suitable hydrogenation condition for PVP/HAc Pd is to use 0 1 mol/L ethanol solution of potassium hydroxide as the hydrogenation medium and the hydrogenation is carried out at 45 ℃.
基金Science Technology Foundation of Jilin Province (200223)
文摘The catalytic activity of poly（styrene-acrylic acid） （PSAA） supported neodymium chloride （NdCl3） complex for the copolymerization of styrene and 4-Vinylpyridine was studied. The influence of various factors, such as Al/Nd molar ratio, reaction time, macromolecular carder （PSAA）, and ratio of styrene to 4-vinypyridine （g/g）, on the copolymerization yield of styrene and 4-Vinylpyridine was investigated. The results showed that the copolymerization of polar monomers with olefins occurred efficiently and the catalytic activity of polymer-supported catalyst was higher than that of the similar small molecular catalysts. The activity of PSAA.Nd complex increased with in- creasing Al/Nd molar ratios and decreased with increasing polymerization time. The highest activity of PSAA＇Nd was observed at 120 min, and the highest yield was found at the ratio of styrene to 4-vinylpyridine of 4：2. DSC analysis presented that the resulted polymer had only one glass transition temperature, and showed very good thermal stability.
基金National Natural Science Foundation of China (No. 20272062)
文摘Polyethylene (PE) grafting 4-vinylpyridine copolymers has been produced as powders of different rushes by theirradiation method. After treatment with methylaluminoxane (MAO), the copolymers were used as supports for Cp_2ZrCl_2catalyst Results of X-ray photoelectron spectroscopy, Fourier transforms infrared spectroscopy, ultraviolet spectroscopy andscanning electron microscope measurements show that the catalytic sites have been linked through MAO on the PE-graft-4-vinylpyridine (PEVP). The percentages of grafting 4-vinylpyridine and supported Cp_2ZrCl_2 depend on the size ofpolyethylene powder. The smaller the polyethylene powder, the more percent of 4-vinylpyridine groups and Cp_2ZrCl_2 existon the polyethylene chains, and the PEVP-supported catalyst has a relatively high activity for ethylene polymerization.
文摘Polymerization of 4-vinylpyridine by complex catalyst of neodymium chloride was studied. The influence of Al/Nd (molar ratio), concentration of catalyst, reaction time and temperature on polymerization of 4-vinylpyridine was investigated. The results show that different kinds of ligand in the rare earth complex have an effect on the catalytic activity of the complex. The catalytic activity of the rare earth complex is higher than that of simple rare earth chloride. The catalytic activity of polymer-supported catalyst is higher than those of the similar small molecular system.
基金Supported by the National Natural Science Foundation of China(No.20674023)
文摘Poly（4-vinylpyridine）（P4-VP） nanofiber and fluoresent poly（4-vinylpyridine）/porphyrin（P4-VP/TPPA） nanofiber were respectively prepared by electrospinning. The effect of the concentration of P4-VP/dimethylformamide （DMF） electrospinning solutions on the morphology of P4-VP nanofiber was investigated and it was found that the average diameter of the nanofiber of P4-VP/DMF increased with the increase of the concentration of the spinning solution. After the addition of TPPA to the P4-VP/DMF spinning solution, the diameter of P4-VP/TPPA nanofiber became even due to the increase of the conductivity of the P4-VP/DMF-TPPA solution. The photoluminescent（PL） spectral analysis indicates that the emission peak position of P4-VP/TPPA nanofiber is almost the same as that of pure TPPA at about 650 nm without peak shift, and when it was stored for 20 days, the emission peak of P4-VP/TPPA nanofiber is also at 650 nm, indicating that the fluorescent property of P4-VP/TPPA nanofiber is stable. Fourier-transform iufrared（FTIR） spectrum confirms the chemical composition of the resulting P4-VP/TPPA composite nanofiber.
基金The project was supported by the National Natural Science Foundation of China
文摘Poly(styrene-co-4-vinylpyridine)-neodymium complexes(NdCl_3·PS4VPY)with variouscontents of the functional group and neodymium have been prepared and characterized.Theinfrared and X-ray photoelectron spectra indicate that uncoordinated 4-vinylpyridine(4VPY)unitsremain in the NdCl_3·PS4VPY complexes.The catalytic behaviour of NdCl_3·PS4VPY was described briefly.
文摘The catalytic activity of poly（styrene-cryli- caeid） （PSAA） supported neodymium chloride （NdCl3） complex for the copolymerization of styrene and 4-vinylpyridine was studied. The influence of various factors, such as Al/Nd molar ratio, reaction time, and ratio of styrene to 4-vinypyridine （g· g^-1 ）, on copolymerization of styrene and 4-Vinylpridine was investigated. The results show that the copolymerization of polar monomers with olefins occurs efficiently. The catalytic activity of polymer-supported catalyst is higher than that of the similar small molecule catalysts. The activity of PSAA· Nd complex increases with increasing Al/Nd ratios and decreases with increasing polymerization time, the highest activity of PSAA· Nd is observed at 120 min. High yield is found at the ratio of styrene to 4-vinylpyridine is 4：2. The resulted polymer shows very good thermal stability.
基金This work was supported by the National Natural Science Foundation of China(Nos.90206020 and 29901001).
文摘In the UV-Vis spectra of pure light-scattering systems, there is an exponential relationship between absorbance and wavelength （A = Kλ^-n）. Here, the exponent n is named as flocculation-coagulation parameter. In the present paper, the effects of different additives on the stability of poly（N,N＇-methylenebisacrylamide-co-4-vinylpyridine） （poly（Bis-co-4-VP）） microgel dispersion were studied in detail via this parameter. The results showed that the stability of the dispersion mainly comes from the ionization of pyridine groups, making the microgel positively charged on its surface. This was confirmed by the measurement of Zeta potential and the result of conductometric titration. The result of fluorescence analysis indicated that the hydrophobicity in the microgels is enhanced with the increase in total 4-VP unit content.
文摘An facile and efficient protocol for the synthesis of 13‐aryl‐indeno[1,2‐b]naphtha[1,2‐e]pyran‐ 12(13H)‐ ones has been developed that proceeds via the one‐pot three‐component sequential reaction of an aromatic aldehyde with β‐naphthol and 2H‐indene‐1,3‐dione under solvent‐free conditions in the presence of a poly(4‐vinylpyridinium)hydrogen sulfate(P(4‐VPH)HSO4) catalyst. The catalyst can be reused several times, making this procedure facile, practical, and sustainable. The simple experimental procedure, solvent‐free reaction conditions, use of an inexpensive catalyst, short react time, and excellent yields are some of the major advantages of this methodology.
文摘With concerns in energy crisis and global warming, researchers are actively investigating alternative energy renewable solutions. Among the various methods, piezoelectric transduction stands out due to its impressive electromechanical coupling factor and coefficient. As a result, piezoelectric energy harvesting has garnered significant attention from the scientific community. In this study, we explored methods to enhance the piezoelectric properties of polyvinylidene fluoride (PVDF) through two distinct approaches. The first approach involved applying external high voltages at various stages during the mixture reaction. The goal was to determine whether this voltage application could alter or enhance PVDF’s piezoelectric conformation by improving the alignment of polarized dipoles. In the second part of our study, we investigated the effects of incorporating various nanostructures (including Iron Oxide, Magnesium Oxide, and Zinc Oxide) into PVDF. To analyze changes in PVDF’s crystalline structure, we utilized Fourier Transform Infrared Spectroscopy (FTIR) and X-ray Diffraction (XRD) techniques. Additionally, we measured the electric polarization of samples using a Precision LC Meter and examined the morphology of nanofibers through Scanning Electron Microscopy (SEM).
