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41.
Zahid Qamar M. Zakria Rana Iqtidar Shakoor Muhammad Raffi Mazhar Mehmood A. Mahmood 《Journal of Polymer Research》2017,24(3):39
This research work reports on development and characterization of multi-walled carbon nanotube (MWCNT)-doped polyvinylidene difluoride (PVDF) nanofibers by the electrospinning method. PVDF is an extensively studied polymer both theoretically and experimentally due to its appealing ferroelectric, piezoelectric, and pyroelectric properties which strongly favors its promising applications in the development of micro/nanostructure devices. The foremost reason for its ferroelectric and piezoelectric behaviors has been attributed to its crystalline structure, specifically the presence of β-phase; however, the existence of the small percentage of β-phase in pristine PVDF limits its applications. To enhance the electroactive features in the PVDF, MWCNTs have been doped in it to prepare electrospun nanofibers, as electrospinning is a single-step approach. These nonwoven nanofibers were prepared at a DC voltage of 20 kV which were subsequently calcined at 100 °C for 12 h. The estimation of crystal structure and phase identification in these nanofibers have been determined by attenuated FT-IR and XRD, while the morphology, microstructure, mean diameter, and length have been examined by FE-SEM. The observed electrical conductivity, capacitance, permittivity (ε), conductivity (δ), and impedance (Z) in these samples have been tailored by doping a range of MWCNT contents and optimizing the experimental conditions. 相似文献
42.
Au/PANA/PVAc and Au/P(ANA-co-CNTA)/PVAc electrospun nanofibers as tyrosinase immobilization supports
Au/poly anthranilic acid/poly vinyl acetate and Au/poly(anthranilic acid-co-3-carboxy-N-(2-thenylidene)aniline)/poly vinyl acetate nanofibers through electrospinning and their modification with covalent tyrosinase (Ty) immobilization was performed. It was realized by surface activation using N-(3-dimetylaminopropyl)-N-ethylcarbodimide hydrochloride/N-hydroxysuccinimide chemistry. Electrochemical impedance spectroscopy (EIS), FTIR–ATR, Raman spectroscopy, and bicinchoninic acid assay analyses demonstrated that Ty was stably and covalently bonded onto the nanofibers. Increase in surface roughness [atomic force microscopy (AFM)] and the presence of Cu atoms in the nanofiber composition after enzyme immobilization confirmed the Ty immobilization. The charge transfer resistances of the nanofibers decreased due to changes in the nanofiber surfaces after attachment of enzyme. 相似文献
43.
The chemical graft copolymerization reactions were used to enhance water resistance of paper by reaction of acrylonitrile (AN) monomer onto cellulosic paper sheet in the presence of comonomer (styrene or acrylic acid or itaconic acid) 1 : 1 molar ratio in dimethyl formamide using benzoyl peroxide as free radical initiator under nitrogen atmosphere at 70°C. The infrared spectroscopy confirms that graft copolymerization reaction occurs onto the paper samples. Water absorption test was carried out following the Normal Protocol 7/81 (water absorption by complete immersion) to evaluate the protective effect of the graft treatment onto the paper sheet. It was found that the three graft copolymerization systems reduced the water absorption of the investigated paper and the reduction of water absorption is directly proportional to the grafting %. The wettability of the grafted and ungrafted paper sheet samples were investigated using the wicking time method which exhibits the decreasing of paper sheet wettability using the AN/S comonomers in the graft copolymerization reaction. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013 相似文献
44.
Bhawan Singh Bharat Singh Rana L. N. Sivakumar Gajendra M. Bahuguna Anil K. Sinha 《Journal of Porous Materials》2013,20(2):397-405
A series of hierarchical mesoporous TS-1 zeolites with MFI structure were successfully synthesized via hydrothermal route using amphiphilic organosilanes as pore directing templates. These materials were characterized by nitrogen sorption (for surface area, pore volume and pore size distribution), FTIR, SEM and UV–Visible spectroscopy. These materials are efficient catalysts for liquid phase epoxidation of olefins using TBHP as the oxidant. All these TS-1 samples oxidized cyclohexene selectively into epoxide. For the TS-1 sample with 4.4 % Ti complete conversion of cyclohexene into epoxide was observed. 相似文献
45.
Aiman E. Al-Rawajfeh Ehab M. Al-Shamaileh Khaldoon Al-Whoosh Ala’a Al-Ma’abrah Ramzi Al-Zorqan Rana Zanoon Khalid Rawajfeh Saleh Al-Jufout 《Journal of Industrial and Engineering Chemistry》2013,19(6):1895-1902
The release of chlorine in the electrodeionization (EDI) unit causes corrosion in the EDI unit, damaging ion exchange membranes and creating a safety risk for the workers. In this work, adsorption desalination of Cl? ions on low-cost composite synthetic–natural Jordanian materials were investigated as an approach to prevent the release of corrosive chlorine gas at the positive electrode. The percentage removal reaches 25% at 25 min shaking time to 55% at 120 min, in a single batch experiment. The values of ΔH0, ΔS0, and ΔG0 indicate the favorability of physisorption. Zeolite and Pozzolana represent potential adsorbents of chloride. 相似文献
46.
Electrocopolymerization of a binary mixture of 3‐chloroaniline and 2‐amino‐4‐phenylthiazole on platinum electrode in acid medium was carried out under different reaction conditions such as temperature, current density, hydrochloric acid, and monomer concentrations with duration time. The initial rate of the electrocopolymerization reaction on platinum electrode is small and the rate law is Rp = K2 [D]1.29[HCl]0.97[M]1.94. The apparent activation energy is found to be 38.87 kJ/mol. The obtained copolymer film is characterized by 1H‐NMR, elemental analysis, GPC IR, UV‐visible, and cyclic voltammetry and compared with those of the two homopolymers. The mechanism of the electrocopolymerization reaction is also discussed and the monomer reactivity ratio (r1and r2) is calculated. The thermogravimetric analysis (TGA) is used to confirm the proposed structure and determination of the number of water molecules in the polymeric chain unit. X‐ray and scanning electron microscopic analysis are used to investigate the surface morphology. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 2076–2087, 2005 相似文献
47.
Khani Ali Eskandani Morteza Derakhshankhah Hossein Soleimani Khadijeh Nakhjavani Sattar Akbari Massoumi Bakhshali Jahanban-Esfahlan Rana Moloudi Kave Jaymand Mehdi 《Journal of Polymer Research》2022,29(4):1-10
Journal of Polymer Research - Derivatives of formyl pyrazole were synthesized by the reaction of acetophenone, 4-methyl acetophenone, 3-acetyl furan, 3-acetyl thiophen and phenyl hydrazine... 相似文献
48.
S. M. Sayyah M. A. EI-Ahdal Z. A. El-Shafiey M. El-Sockary U. F. Kandil 《Journal of Polymer Research》2000,7(2):97-106
Anionic solution polmerization studies of benzylidene malononitrile, benzylidene ethyl cyanoacetate and their para chloro derivtives in dimethyl formamide (DMF) as a reaction medium using pipridene as initiator under nitrogen atmosphere at 100 °C were carried out. Infrared, 1H NMR and ultraviolet-visible (UV-Vis) spectroscopic studies for the obtained polymers were investigated. The effect of γ-irradiation on PMMA films doped with 1 % of the benzylidene polymers was investigated by uv-vis spectroscopy. A change in the intensity of absorption bands with increasing irradiation dose was recorded. It is suggested that PMMA films doped with this type of benzylidene polymer can be used as dosimeter. 相似文献
49.
Hanjin Kwag Dipak Rana Kyucheol Cho Jangweon Rhee Taewoo Woo Byung H. Lee Soonja Choe 《Polymer Engineering and Science》2000,40(7):1672-1681
The rheology and morphology of four sets of binary blends of polyethylene synthesized with metallocene catalysis (metallocene polyethylene: MCPE) with polyolefins prepared using Ziegler‐Natta catalysts have been investigated. The blend systems are MCPE with high density polyethylene (MCPE‐HDPE), polypropylene (MCPE‐PP), poly(propylene‐co‐ethylene) (MCPE‐CoPP), and poly(propylene‐co‐ethylene‐co‐1‐butylene) (MCPE‐TerPP). Cole‐Cole plots [storage melt viscosity (η′) versus loss melt viscosity (η″)], plots of the dynamic storage modulus (G′) versus the dynamic loss modulus (G″), and plots of the log melt viscosity (η*, η′, and η″) versus blend compositions were constructed. The morphology of the blends after microtoming and etching was studied. The phase morphology of MCPE‐HDPE appeared homogeneous, whereas the other three blends were heterogeneous. Rheological and morphological investigations indicated that the MCPE‐HDPE blend was miscible, but the other three blends were immiscible in the melt as well as in the solid state. These observations can be rationalized in terms of the similarity of the chemical structures of the polyolefins. 相似文献
50.
Dipak Rana Hak Lim Kim Hanjin Kwag Jangweon Rhee Kyucheol Cho Taewoo Woo Byung H. Lee Soonja Choe 《应用聚合物科学杂志》2000,76(13):1950-1964
The rheological and morphological behaviors of commercially available three binary blends of ethylene 1‐octene copolymer (EOC) regarding the melt index (MI), density and comonomer contents, one component made by the Ziegler–Natta and the other by the metallocene catalysts, were investigated to elucidate miscibility and phase behavior. Miscibility of the EOCs blend in a melt state was related to the value of the MI, density, and comonomer content. If the comonomer contents are similar, then the melt viscosity is weight average value, otherwise it is positively or negatively deviated. The microtomed surface prepared by two different cooling processes—one is fast cooling and the other is slow cooling—indicated that all the blends were not homogenous regardless the density, MI, and comonomer content. The Ziegler–Natta catalyzed EOCs exhibited bigger spherulitic diameter and larger ring space than those of the metallocene EOCs prepared by a cooling process. The blends consisting of similar MI showed banded spherulites with different diameter, whereas the blend consisting of different MI and density takes place of explicit phase separation and phase inversion at 1 : 1 blend composition. The melt rheology appeared to influence the mechanical and film properties in the solid state. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 76: 1950–1964, 2000 相似文献