Electrospinning technique for the fabrication of poly(styrene-co-methyl methacrylate) nanofibers and the effect of fiber diameter on UV–Visible absorption and thermal properties

2020 ◽  
Vol 33 ◽  
pp. 2077-2081
Author(s):  
Vinitha Varkey ◽  
E. Tomlal Jose ◽  
U.S. Sajeev
Keyword(s):  
Thermal Properties ◽  
Methyl Methacrylate ◽  
Fiber Diameter ◽  
Electrospinning Technique ◽  
Visible Absorption ◽  
Uv Visible

TiO2 nanofibers fabricated by electrospinning technique and degradation of MO dye under UV light

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Naveen Thakur ◽  
Nikesh Thakur ◽  
Viplove Bhullar ◽  
Saurabh Sharma ◽  
Aman Mahajan ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Fiber Diameter ◽  
Uv Light ◽  
Rutile Phase ◽  
Powder Form ◽  
X Ray Diffraction ◽  
Electrospinning Technique ◽  
Tio2 Nanofibers ◽  
X Ray ◽  
Uv Visible

Abstract Titanium dioxide (TiO2) nanofibers were synthesized by electrospinning to optimize the photocatalytic action efficiency. The synthesis of the fibers was carried out at four different wt% concentrations: 8, 9, 10 & 11% of polymer polyvinylpyrrolidone (PVP). The TiO2 fibers were further calcined at 700 °C to get powder form. The uncalcinated and calcined TiO2 nanofibers were characterized by using X-Ray diffraction (XRD), Raman spectroscopy, Scanning electron microscopy (SEM) and UV-Visible spectroscopy. Raman spectroscopy confirmed the rutile phase of the calcined TiO2nanofibers in powder form with a crystallite size of 34–38 nm. The surface morphology of the uncalcinated and calcined TiO2 nanofibers was examined by SEM and the fiber diameter found to be 360–540 nm. The optical bandgap of the calcined TiO2 nanofibers was found in the range of 3.29–3.24 eV. The photocatalytic activity of the TiO2 nanofibers as examined for uncalcinated and calcined nanofibers, methyl orange (MO) dye degraded up to 98 and 78%, respectively in 180 min under the exposure of UV light. Uncalcinated TiO2 nanofibers were found more suitable for degradation of MO dye as compared to calcined nanofibers.

Study of Electron Beam Pre-Irradiation on Char Yields of Polyacrylonitrile

2020 ◽  
Vol 996 ◽  
pp. 35-40
Author(s):  
Hai Xiao ◽  
Pei Kai Miao
Keyword(s):  
Electron Beam ◽  
Thermal Properties ◽  
Thermal Treatment ◽  
Irradiation Dose ◽  
Radiation Effects ◽  
Visible Absorption ◽  
Thermal Behaviors ◽  
Molecular Weights ◽  
Polymeric Chains ◽  
Uv Visible

Thermal treatment of polyacrylonitrile (PAN) with different molecular weights pre-irradiated by electron beam was prepared to study the radiation effects on thermal behaviors. Thermal properties were characterized by thermogravimetric analyses. Char yields (800 oC) of PAN samples are increased remarkably with the increase of irradiation dose, and all samples can obtain the similar high char yields (~57 %) at the dose of 300 kGy. FTIR and UV-visible absorption spectra of pre-irradiation PAN illustrate the formation of –HC=N-N=CH-crosslinking conjugation across the polymeric chains, which can improve PAN’s thermal behaviors. Char yields of pre-irradiated PAN samples are mainly dominated by their gel contents, and they are almost independent of the molecular weights of PAN samples.

scholarly journals Optical and thermal properties of novel diazine-based oligo(phenylene vinylene)s

e-Polymers ◽  
2003 ◽  
Vol 3 (1) ◽  
Author(s):  
Michaël Mainil ◽  
Laurent Pascal ◽  
Jean-Jacques Vanden Eynde ◽  
Yves Van Haverbeke ◽  
Philippe Dubois
Keyword(s):  
Thermal Properties ◽  
Emission Spectroscopy ◽  
Phenylene Vinylene ◽  
Thermal Transitions ◽  
Scanning Calorimetry ◽  
Visible Absorption ◽  
X Ray ◽  
Conjugated Systems ◽  
X Ray Scattering ◽  
Uv Visible

Abstract New electro-conjugated diazine-based oligo(phenylene vinylene) derivatives with some interesting optical and thermal properties have been synthesised and characterised. These conjugated systems are built up on two benzenic cycles linked to a central diazine, either pyrimidine or pyrazine, through a carbon-carbon double bond. Both benzenic rings are substituted by one or two alkoxy chains. The length, the position and the number of alkoxy chains per benzenic ring have been varied and have proved to modulate both optical and thermal properties. Optical properties have been studied by UV-visible absorption spectroscopy as well as emission spectroscopy. Differential scanning calorimetry, wide-angle X-ray scattering and optical microscopy under crossed polarizers have been applied for characterising the thermal transitions and crystalline changes occurring in these conjugated systems.

Remarkable kinetic stability of α-thiocarbamoyl substituted 4-methoxybenzylcations

1998 ◽  
Vol 76 (12) ◽  
pp. 1910-1915 ◽  
Author(s):  
Robert A McClelland ◽  
Victoria E Licence ◽  
John P Richard ◽  
Kathleen B Williams ◽  
Shrong-Shi Lin
Keyword(s):  
Key Words ◽  
Strong Interaction ◽  
Rate Constants ◽  
Flash Photolysis ◽  
Visible Absorption ◽  
Methyl Group ◽  
Thioamide Group ◽  
Azide Ion ◽  
Uv Visible ◽  
Leaving Groups

4-Methoxybenzyl cations bearing α-(N,N-dimethylcarbamoyl) and α-(N,N-dimethylthiocarbamoyl) substituents have been generated photochemically upon irradiation of precursors with pentafluorobenzoate or 4-methoxybenzoate leaving groups. The ions have been observed with flash photolysis in 40:60 acetonitrile:water and in 50:50 methanol:water, and rate constants were measured for their decay in solvent alone and for their capture by azide ion. The cations so studied and their lifetimes in 40% acetonitrile are 6, ArC+H-CONMe2, 0.6 μs; 2, ArC+H-CSNMe2, 7 ms; and 4, ArC+(CH3)-CSMe2, 6 ms, where Ar = 4-MeOC6H4. The cation 4 reacts with solvent by elimination of a proton from the α-methyl group, and the rate constant for solvent addition must be less than 1 s-1. The CSNMe2 substituted cations are 105-107-fold longer lived than analogs where the thioamide group has been replaced with an α-methyl. The UV-visible absorption spectra of these two cations also show significant differences from those of typical 4-methoxybenzyl cations. Thus, both the lifetimes and spectra point to a strong interaction of the benzylic centre with the thioamide group. Key words: flash photolysis, thiocarbamoyl stabilized carbocation, photosolvolysis.

scholarly journals Water-soluble β-aminobisulfonate building blocks for pH and Cu2+ indicators

RSC Advances ◽  
2016 ◽  
Vol 6 (88) ◽  
pp. 84712-84721 ◽  
Author(s):  
Maria A. Cardona ◽  
Marina Kveder ◽  
Ulrich Baisch ◽  
Michael R. Probert ◽  
David C. Magri
Keyword(s):  
Nmr Spectroscopy ◽  
Building Blocks ◽  
Water Soluble ◽  
Visible Absorption ◽  
H Nmr ◽  
Uv Visible

Two phenyl β-aminobisulfonate ligands characterised by UV-visible absorption, EPR and 1H NMR spectroscopy exhibit evidence for binding with Cu2+ in water and methanol.

Effect of needle diameter on nanofiber diameter and thermal properties of electrospun poly(methyl methacrylate)

2007 ◽  
Vol 18 (3) ◽  
pp. 180-183 ◽  
Author(s):  
Javier Macossay ◽  
Alexis Marruffo ◽  
Roman Rincon ◽  
Tom Eubanks ◽  
Anxiu Kuang
Keyword(s):  
Thermal Properties ◽  
Methyl Methacrylate ◽  
Poly Methyl Methacrylate ◽  
Nanofiber Diameter ◽  
Needle Diameter

Study on the Inclusion Behavior of Cucurbit [n] uril with Phenylalanine

2011 ◽  
Vol 197-198 ◽  
pp. 1153-1156
Author(s):  
Ning Chen ◽  
Ya Bin Li
Keyword(s):  
1H Nmr ◽  
Interaction Mechanism ◽  
Acetate Buffer Solution ◽  
Molar Ratio ◽  
High Concentration ◽  
Buffer Solution ◽  
Visible Absorption ◽  
Nmr Spectrum ◽  
Application Range ◽  
Uv Visible

The characteristics of host-guest complexes between cucurbit[n]uril (CB [n]) and phenylalanine were investigated by UV-visible absorption spectroscopy in acetate buffer solution at room temperature. It was found that the UV-visible absorption increased steadily with constantly dropping the high concentration of cucurbit[6]uril (CB [6]) and cucurbit[8]uril (CB [8]) in the phenylalanine solution which indicates that there are some interaction betweenCB [n] and phenylalanine.Then CB [6] and phenylalanine at molar ratio of 1:1 to weigh while CB [8] and phenylalanine at molar ratio of 1:2, respectively, are both demonstrated by 1H NMR spectra. 1H NMR spectrum of complexes was obtained, indicating an enthalpic driving force for host-guest complexes. The possible interaction mechanism and inclusion mode were also discussed. This work may extend the application range of CB [n] in supramolecular and pharmaceutical analysis.

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