Papers by Vijaya Sangawar
Scientific Reviews and Chemical Communications, 2012
Polyvinyl chloride (PVC) has been modified by addition of (C + MnO 2 ).The addition is 5% and 20%... more Polyvinyl chloride (PVC) has been modified by addition of (C + MnO 2 ).The addition is 5% and 20% by weight. (C + MnO 2 ) act as a reducing agent and used in dry cells.Short circuit and air gap thermally stimulated conductivity have been studied in the temperature range 303K to 383K. It has been observed that conductivity of (C + MnO 2 ) added PVC is higher than undoped PVC but it is higher for 5 wt. % than 20 wt. % of (C + MnO 2 ).Activation energy values were determined from the slope of log σ vs 1000/T plot and represent electronic conduction in modified PVC and ionic in undoped PVC.
Most of the synthetic polymers are petrochemical based and are not biodegradable. the persistent ... more Most of the synthetic polymers are petrochemical based and are not biodegradable. the persistent of these synthetic polymers nowadays are major source of an environmental pollution. These indirectly affect the preservation of ecological systems and also harming wildlife when they are dispersed in nature. For example, the effects of plastic bags are well-known to affect nature life’s, sea life’s etc.For these different reasons, degradation of these petrochemical based synthetic plastics polymers is required. The paper presents review of different approaches to degrades the synthetic plastic polymers to avoid environmental pollution and to preserve an ecological system
Journal of Taibah University for Science, Oct 1, 2016
Polyethylene microspheres (microparticles) were prepared using a modified chemical route. The pre... more Polyethylene microspheres (microparticles) were prepared using a modified chemical route. The prepared powder samples were characterized using scanning electron microscopy, Fourier transform infrared spectroscopy and differential scanning calorimetry. The scanning electron microscopy images show that the concentration of polyglycolic acid decreased the agglomeration and increased the degree of sphericity of the polyethylene microspheres. The results show that the polyethylene microparticles may be good candidates as drug carriers for pulmonary drug delivery.
An attempt has been made to prepare polyvinyl alcohol (PVA) based gel electrolyte in ammonium thi... more An attempt has been made to prepare polyvinyl alcohol (PVA) based gel electrolyte in ammonium thiocyanate(NH4SCN) solution and to characterised it by SEM, FTIR & UV-absorption study. SEM revealed in the 0.5gm and 2.5gm PVA+NH4SCN gel electrolyte, PVA acts as the backbone and NH4SCN particle are distributed randomly both on the surface and in the internal structure of PVA backbone. FTIR result indicates the presence of active interaction between PVA and NH4SCN in these gel electrolytes. From UV- study, the direct band gap is calculated ,and it found that it decreases from 5.57 ev to 3.17ev as PVA concentration increases in gel electrolyte.
Ukrainian Journal of Physics, 2017
Nanostructured thin films have attracted the attention of an increasing number of researchers fro... more Nanostructured thin films have attracted the attention of an increasing number of researchers from several disciplines during the last ten years, due to their outstanding electronic and optical properties and extensively useful applications in various optoelectronic devices. PbS thin films were deposited onto glass substrate by the method of chemical bath deposition (CBD) at 330 K temperature. The structure and surface morphology of the films were characterized by X-ray diffraction and scanning electron microscopy. The optical investigation showed that, depending on thickness films have direct allowed transitions in the range 1.88-2.28 eV. The decrease in dc dark resistivity with increase in grain size was also studied. The thermo-emf measurements show that deposited films were p-type in nature.
Chemical science transactions, Aug 25, 2012
An attempt has been made to prepare polyvinyl alcohol (PVA) based proton conducting gel electroly... more An attempt has been made to prepare polyvinyl alcohol (PVA) based proton conducting gel electrolytes in ammonium thiocyanate (NH 4 SCN) solution and to characterize them. XRD studies revealed that the entire gel sample are amorphous in nature with a broad peak at nearly 2θ=22 0 . Variation of conductivity of gel electrolyte with loading concentration of PVA has also been studied. It has been observed, as loading of PVA in 0.2 M electrolyte of NH 4 SCN+DMSO increases conductivity decreases. The conductivity of gel electrolytes exhibits liquid like nature at low polymer concentration while the behaviour is seen to be affected by the formation of PVA-NH 4 SCN complexes upon increase in polymer content beyond 2 g. Temperature dependence of ionic conductivity exhibits VTF and Arrhenius behaviour.
Bulletin of Materials Science, Oct 1, 2014
The present work deals with transmission electron microscopy (TEM), X-ray diffraction (XRD), diff... more The present work deals with transmission electron microscopy (TEM), X-ray diffraction (XRD), differential scanning calorimetry (DSC) and thermally stimulated discharge current (TSDC) study of inorganic metal oxide (ZnO) nanoparticles and its thermoelectrets. The thermoelectrets were prepared by applying different electric polarizing field (E P) at constant polarizing temperature (T P), for constant polarization time (t p). The TSDC study was carried out in the temperature region of 313-473 K. It was observed that the conductivity of ZnO samples increases with the increase in temperature and polarizing field. The dependence of TSDC data on polarizing agents, i.e. field and temperature shows Arrhenius type of behviour and is explained on the basis of variable range hopping mechanism.
Der Pharmacia Lettre, 2021
The development of society and increasing consumption of plastics in the world has been a subject... more The development of society and increasing consumption of plastics in the world has been a subject of great concern and special attention by the scientific community. The aim of this research paper to synthesize and characterize Cellulose + PEG added LDPE biocomposite thin film buried in natural compostable soil environment for the period up to 180 days. The Cellulose (CEL) added 7 wt. % PEG/LDPE biocomposite thin films having 10 wt. % of CEL were characterized by weight loss and weight loss percent, UTS and PEB measurements, SEM and XRD before and after degradation in order to study biodegradation of CEL/PEG/LDPE thin film samples under natural environment. The LDPE+7% PEG+10% CEL biocomposite thin films after soil burial of 90, 120, 180 days are found to be degraded and makes an eco-friendly and degradable material in natural environment.
This paper describes the studies related to ZnO nanoparticles (0, 0.5, 1, 3 and 5 wt. %) filled L... more This paper describes the studies related to ZnO nanoparticles (0, 0.5, 1, 3 and 5 wt. %) filled Low Density Polyethylene (LDPE) thin films prepared by solution casting technique. The synthesized ZnO/LDPE nanocomposite thin films were analyzed by XRD, SEM and FTIR. Peaks in X-Ray Diffraction (XRD) pattern indicate the presence of ZnO nanoparticles in LDPE matrix and absence of any extra peak in the pattern shows there is no new phase formation. The Scanning Electron Microscope (SEM) images showed that the nano inclusions are uniformly distributed in the LDPE matrix. Fourier Transform Infrared (FTIR) result indicates the presence ZnO nanoparticles in LDPE thin films.
PVA gel electrolyte with different concentration of PVA (0.5, 1 ,1.5, 2 ,2.5 by weight) in KSCN+D... more PVA gel electrolyte with different concentration of PVA (0.5, 1 ,1.5, 2 ,2.5 by weight) in KSCN+DMSO electrolyte has been prepared by simple technique and characterized by X-RD and measuring d.c. conductivity electrical conductivity as a function of temperature in the range 00to 1000c . Variation of conductivity of gel electrolyte with loading concentration of PVA has also been studied .It has been observed that all gel sample are amorphous in nature with shifting a broad peak. As loading of PVA in 0.2 M electrolyte of KSCN+DMSO increases conductivity decreases. But conductivity is found to be increases with increases in temperature for all sample consisting VTF and Arrhenius behavior.
Materials Science-Poland, 2013
ABSTRACT The nanocrystalline powders of pure and Al3+-doped ZnO with hexagonal structure were pre... more ABSTRACT The nanocrystalline powders of pure and Al3+-doped ZnO with hexagonal structure were prepared by a simple hydrothermal decomposition route. The structure and crystal phase of the powders were characterized by X-ray diffraction (XRD) and the microstructure by transmission electron microscopy (TEM). All the compositions exhibited a single phase, suggesting a formation of solid solution between Al2O3 and ZnO. DC electrical properties of the prepared nanoparticles were studied by DC conductivity measurements. The indirect heating structure sensors based on pure and doped ZnO as sensitive materials were fabricated on an alumna tube with Au electrodes. Gas-sensing properties of the sensor elements were measured as a function of concentration of dopant, operating temperature and concentrations of the test gases. The pure ZnO exhibited high response to NH3 gas at an operating temperature of 200 °C. Doping of ZnO with Al3+ increased its response towards NH3 and the Al3+-doped ZnO (3.0 wt% Al2O3) showed the maximum response at 175 °C. The selectivity of the sensor elements for NH3 against different reducing gases like LPG, H2S and H2 was studied. The results on response and recovery time were also discussed.
Talanta, 2009
Perovskite type LaCo x Fe 1−x O 3 nanoparticles was synthesized by a sol-gel citrate method. The ... more Perovskite type LaCo x Fe 1−x O 3 nanoparticles was synthesized by a sol-gel citrate method. The structural, electrical and sensing characteristics of the LaCo x Fe 1−x O 3 system were investigated. The structural characteristics were performed by using X-ray diffraction (XRD) and transmission electron microscopy (TEM) to examine the phase and morphology of the resultant powder. The XRD pattern shows nanocrystalline solid solution of LaCo x Fe 1−x O 3 with perovskite phase. Electrical properties of synthesized nanoparticles are studied by DC conductivity measurement. The sensor shows high response towards ammonia gas in spite of other reducing gases when x = 0.8. The effect of 0.3 wt.% Pd-doped LaCo 0.8 Fe 0.2 O 3 on the response and a recovery time was also addressed.
Sensors and Actuators B: Chemical, 2008
In this paper, the structural and gas sensing properties of nanocrystalline La0.7Pb0.3Fe0.4Ni0.6O... more In this paper, the structural and gas sensing properties of nanocrystalline La0.7Pb0.3Fe0.4Ni0.6O3 was prepared by a sol–gel citrate method. The structural characteristics of the material were studied by using X-ray diffraction (XRD) and transmission electron microscopy (TEM). The XRD pattern shows a nanocrystalline solid solution of La0.7Pb0.3Fe0.4Ni0.6O3 with a perovskite phase. The gas sensing properties were studied for different reducing gases such as H2S, ethanol, CO and LPG. The La0.7Pb0.3Fe0.4Ni0.6O3 powder showed large response to H2S gas at an operating temperature 250°C. Further improvement in response was achieved by the addition of 0.5wt% Pd to La0.7Pb0.3Fe0.4Ni0.6O3. The sensor showed a good response to 150ppm H2S gas at an operating temperature 200°C.
Current Applied Physics, 2011
ABSTRACT Nanocrystalline La1−xSrxFeO3 (x = 0, 0.1, 0.2, 0.3 and 0.4) was prepared by sol–gel citr... more ABSTRACT Nanocrystalline La1−xSrxFeO3 (x = 0, 0.1, 0.2, 0.3 and 0.4) was prepared by sol–gel citrate method. The structural and microstructural characterization has been carried out with the help of X-ray diffraction (XRD) and transmission electron microscopy (TEM), respectively. XRD studies confirm the formation of LaFeO3 with perovskite phase. Further studies by Fourier transform infrared spectroscopy were also conducted. DC electrical properties of the prepared nanoparticles were studied by D.C. conductivity measurements. The gas-sensing performance of the as-prepared La1−xSrxFeO3 nanoparticles was investigated towards different reducing gases like acetone (CH3COCH3), ethanol (C2H5OH), hydrogen sulfide (H2S), hydrogen (H2) and liquefied petroleum gas (LPG). The nanocrystalline La0.7Sr0.3FeO3 exhibited good sensing performance towards acetone gas with rapid response and high sensitivity at 275 °C as compared with LaFeO3.
Metal and metal oxide nanoparticles (NPs) have piqued the interest of material scientists in rece... more Metal and metal oxide nanoparticles (NPs) have piqued the interest of material scientists in recent years due to their unique physicochemical properties which are dependent on their size, shape, and chemical surroundings. The sol gel combustion is one of the most straightforward and practical technique for getting tiny and similar size and shape of the powder out of all the current lead oxide nanoparticle synthesis techniques. In this study, PbO nanoparticles are prepared using the sol-gel method followed by an auto combustion process. This research is aimed at the particle size, shape, thermal analysis, and optical properties of nanostructured PbO. Several microscopic, spectroscopic, and thermogravimetric analysis are employed for the structural characterization of lead oxide nanoparticles. Tiny lead oxide particles with a diameter of 60 nanometres have been prepared. The prepares sample's optical band gap was discovered to be 2.44 electronvolt. Thermal investigations indicate ...
Scientific Reviews and Chemical Communications, 2012
The quantum of plastic waste in Municipals Solid Waste is increasing due to increase in populatio... more The quantum of plastic waste in Municipals Solid Waste is increasing due to increase in population, development activities and changes in the lifestyle. As plastic is non-biodegradable in nature, it remain in environment for several years and disposing plastic waste at landfill are unsafe since toxic chemicals leach out into the soil, underground water and pollute the water bodies. Therefore plastic waste disposal is the major problem for the civic authorities.
Thin films of Polystyrene (PS) with different concentrations (0, 0.5, 1, 3 and 5 wt. %) of ZnO na... more Thin films of Polystyrene (PS) with different concentrations (0, 0.5, 1, 3 and 5 wt. %) of ZnO nanoparticles (ZnO NPs) as a filler were prepared by using solution cast technique. Effect of ZnO NPs on optical properties of PS such as absorbance, transmittance, absorption coefficient, refractive index, extinction coefficient, and, real and imaginary parts of dielectric constant have been investigated by measuring optical absorption spectra using UV- Vis spectroscopy. This study reveals that all these parameters are affected by increasing ZnO NPs percentage. The study has been also extended to include the changes in the optical parameters including the band tail width and band gap energies for the samples.
International Journal of Research, 2018
The present study reveals with study of electrical, thermal and optical band gap of polypyrrole f... more The present study reveals with study of electrical, thermal and optical band gap of polypyrrole filled PVC: PMMA thin films themoelctrets. Conducting polymer composites have attracted considerable interest in recent years because of their numeric applications in variety of electric and electronic devices. Polypyrrole has been regarded as one of the most studied conducting polymer because of its physical and electrical properties that have led to several applications such as solid state devices and electronics. The electrical conductivity of polypyrrole filled PVC: PMMA thermoelectrets have been studied. Electret effects in polymers can be produced by orientation of dipoles and /or trapping of charge carriers injected from electrodes as well as generated in the bulk of polymers. It has been shown by thermally stimulated discharge conductivity technique (TSDC) that the characteristics of electrets are very sensitive to the structure of electret forming materials. In this respect TS...
In the present work, Solution growth technique was employed for the preparation of cadmium sulfid... more In the present work, Solution growth technique was employed for the preparation of cadmium sulfide/polystyrene nanocomposite thin films by varying the composition of cadmium sulfide by wt. % (1,5,10 & 15 wt.%) in polystyrene. XRD reveals that CdS/PSt nanocomposite thin films are in single phase having cubic structure. Microstructural analysis using Scanning Electron Microscope (SEM) shows that dispersion of CdS nanoparticles are in polymer matrix, having average particle size of about 20 nm.
International Journal of Innovative Research in Science, Engineering and Technology, 2013
Poly(ethylene oxide) (PEO) complexed with Cadmium sulfide (CdS) are prepared by a solution cast t... more Poly(ethylene oxide) (PEO) complexed with Cadmium sulfide (CdS) are prepared by a solution cast technique. Several experimental techniques such as XRD, SEM, FTIR, DSC, PL and Raman spectroscopy are employed to characterize the sample. The powder X-ray diffraction (XRD) result indicates that the nanoparticles are crystallized in cubic phase. The UV-visible absorption, Differential scanning calorimetry, Photoluminescence and Raman spectra of the sample are recorded and discussed briefly.
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Papers by Vijaya Sangawar