检索结果-南通市图书馆

Journal of Donghua University(English Edition) 2019年第5期36卷 445-450页

作者： WEI Fayun CHENG Yue WU Qianqian LI Ke YANG Lishuang FU Yijun ZHANG Wei ZHANG Yu College of Xinglin Nantong UniversityNantong 226019China College of Textile and Clothing Nantong UniversityNantong 226019China

polyvinylidene fluoride(PVDF)/polyurethane(PU)composite nanofiber membranes were prepared by mixing PVDF and PU at different mass *** microstructure and the crystal structure of the composite nanofiber membranes were analyzed by scanning electron microscopy(SEM),Fourier transform infrared(FTIR)spectroscopy and X-ray diffraction(XRD).The hydrophilicity,mechanical properties and piezoelectric properties were also *** showed that when the mass ratio of PVDF to PU was 9∶1,the fiber membrane had the best microstructure,and the crystal form of PVDF changed fromαcrystal toβcrystal in the *** addition of PU improved the hydrophilicity,mechanical properties,and piezoelectric signal of the fiber *** the mass ratio of PVDF to PU was 9∶1,the tensile strength reached the peak value of(10.39±0.41)N,and the output voltage reached the maximum value of(1.98±0.12)V.

关键词： polyvinylidene fluoride(PVDF) polyurethane(PU) crystal form contact angle tensile strength piezoelectric properties

Fabrication of PVDF nanofibrous hydrophobic composite membranes reinforced with fabric substrates via electrospinning for membrane distillation desalination

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2019年第1期31卷 277-288页

作者： Kuiling Li Deyin Hou Chaochen Fu Kai Wang Jun Wang Key Laboratory of Drinking Water Science and Technology Research Center for Eco-Environmental Sciences Chinese Academy of Sciences State Key Laboratory of Environmental Aquatic Chemistry Research Center for Eco-Environmental Sciences Chinese Academy of Sciences College of Energy and Environmental Engineering Hebei University of Engineering School of Chemical Engineering and Technology Hebei University of Technology

To improve the mechanical properties of the electrospun nanofibrous membrane, the nonwoven fabrics and spacer fabrics were employed as support substrates to fabricate polyvinylidene fluoride(PVDF) nanofibrous composite membranes. The influences of the substrate on membrane morphology, hydrophobicity, pore size and pore size distribution,porosity, mechanical strength and permeability were comprehensive evaluated. The electrospun composite membranes had a three dimension bead-fiber interconnected open structure and a rough membrane surface. The membrane surface presented a multilevel re-entrant structure and all the water contact angles were above 140°. In contrast with the pure PVDF nanofibrous membrane, the stress at break and the elastic modulus of the composite membranes increased by 4.5–16 times and 17.5–37 times, respectively. Since the spacer fabrics had less resistance to mass transfer, the membranes composited with spacer fabrics exhibited greater permeate fluxes compared with the composite membranes with the nonwoven fabrics as *** the membrane distillation test, the highest permeate flux was up to 49.3 kg/m^2/hr at the feed temperature of 80°C. The long-time and repeat operation of membrane distillation desalination indicated the fabricated membrane with a good resistance to scaling and *** results suggested the potential of the electrospun composite membrane for membrane distillation application.

关键词： Membrane distillation Electrospinning Spacer fabric polyvinylidene fluoride Mechanical strength

N, F?Codoped Microporous Carbon Nanofibers as Efficient Metal?Free Electrocatalysts for ORR

在线全文

学校读者我要写书评

暂无评论

Nano-Micro Letters 2019年第1期11卷 164-174页

作者： Tianle Gong Ruoyu Qi Xundao Liu Hong Li Yongming Zhang Shanghai Electrochemical Energy Devices Research Center Shanghai Key Lab of Electrical Insulation and Thermal Aging School of Chemistry and Chemical Engineering Shanghai Jiao Tong University School of Material Science and Engineering University of Jinan

Currently, the oxygen reduction reaction(ORR) mainly depends on precious metal platinum(Pt) catalysts. However, Pt-based catalysts have several shortcomings, such as high cost, scarcity, and poor long-term stability. Therefore, development of e cient metal-free electrocatalysts to replace Pt-based electrocatalysts is important. In this study, we successfully prepared nitrogen-and fluorinecodoped microporous carbon nanofibers(N, F-MCFs) via electrospinning polyacrylonitrile/polyvinylidene fluoride/polyvinylpyrrolidone(PAN/PVDF/PVP) tricomponent polymers followed by a hydrothermal process and thermal treatment, which was achieved for the first time in the literature. The results indicated that N, F-MCFs exhibit a high catalytic activity(E_(onset): 0.94 V vs. RHE, E_(1/2): 0.81 V vs. RHE, and electron transfer number: 4.0) and considerably better stability and methanol tolerance for ORR in alkaline solutions as compared to commercial Pt/carbon(Pt/C, 20 wt%) catalysts. Furthermore, in acidic media, N, F-MCFs showed a four-electron transfer pathway for ORR. This study provides a new strategy for in situ synthesis of N, F-MCFs as highly e cient metal-free electrocatalysts for ORR in fuel cells.

关键词： Metal-free catalyst Oxygen reduction reaction N,F-codoped Carbon nanofiber polyvinylidene fluoride

EFFECT OF MOLECULAR WEIGHT OF PMMA ON β PHASE CRYSTALLIZATION IN HIGHLY ORIENTED PVF_2 FILMS

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 1990年第20期35卷 1705-1708页

作者：陈晔杨德才 Changchun Institute of Applied Chemistry Academia Sinica Changchun 130022 PRC

polyvinylidene fluoride （PVF2） exhibits at least four crystalline phases （α, β, γ, and δ）. Among them, β phase is the most important one because it is directly related to the piezoand pyro-electric activities... 详细信息

关键词： polyvinylidene fluoride polymethyl methacrylate blend morphology.

Engineering a High-Selectivity PVDF Hollow-Fiber Membrane for Cesium Removal

在线全文

学校读者我要写书评

暂无评论

Engineering 2019年第5期5卷 865-871页

作者： Shiyuan Ding Lilan Zhang Yang Li Li’an Hou Institute of Surface-Earth System Science Tianjin UniversityTianjin 300072China Tianjin Key Laboratory of Earth Critical Zone Science and Sustainable Development in Bohai Rim Tianjin UniversityTianjin 300072China State Key Laboratory of Coal Mine Disaster Dynamics and Control Chongqing UniversityChongqing 400044China State Key Laboratory of Water Environment Simulation Beijing Normal UniversityBeijing 100875China Xi’an High-Tech Institute Xi’an 710025China

In this study,a copper ferrocyanide/silica/polyvinylidene fluoride(CuFC/SiO2/PVDF)hollow-fiber composite membrane was successfully synthesized through a facile and effective crosslinking *** PVDF hollow-fiber membrane with embedded SiO2 was used to fix the dispersion of CuFC nanoparticles for cesium(Cs)*** surface morphology and chemical composition of the composite membrane were analyzed using scanning electron microscopy and X-ray photoelectron spectroscopy(XPS).The composite membrane showed a high Cs rejection rate and membrane flux at the three layers of CuFC and 0.5%SiO2,and its Cs rejection rate was not affected by variation in the pH(pH=4–10).The modified membrane could be effectively regenerated many times using ammonium nitrate(NH4NO3).The Cs selectivity performance was verified by an efficient Cs rejection rate(76.25%and 88.67%in 8 h)in a solution of 100 lg L 1 of Cs with 1 mmol L 1 of competing cations(K+and Na+).The CuFC/SiO2/PVDF hollowfiber composite membrane showed a particularly superior removal performance(greater than 90%)in natural surface water and simulated water with a low Cs ***,the CuFC/SiO2/PVDF hollow-fiber composite membrane can be used directly in engineering applications for the remediation of radioactive Cs-contaminated water.

关键词： Cesium removal Composite membrane Copper ferrocyanide polyvinylidene fluoride