Faculty Publications

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Author: search.filters.author.Anandhan, S.Subject: search.filters.subject.Fourier transform infrared spectroscopy

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    Characterization of poly(ethylene-co-vinyl acetate-co-carbon monoxide)/layered silicate clay hybrids obtained by melt mixing
    (2011) Anandhan, S.; Patil, H.G.; Babu, R.R.
    In recent times, polymer-layered silicate nanocomposites have drawn a great deal of attention because they often exhibit tremendous improvements in material properties compared with virgin polymers or conventional microor macro-composites. In the present study, nanocomposites were developed from organically modified clay and poly(ethylene-co-vinyl acetate-co-carbon monoxide) by melt mixing. FTIR spectroscopy reveals that the interaction between the organoclay and EVACO is thermodynamically favored. High resolution wide angle X-ray diffraction and transmission electron microscopy were used to study the morphology of the nanocomposites. Elemental mapping by scanning electron microscopy indicates good dispersion and distribution of the nanoclay in EVACO matrix. The mechanical properties of the nanocomposites are optimum at a clay loading of 3%. © Springer Science+Business Media, LLC 2011.
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    Parametric study of manufacturing ultrafine polybenzimidazole fibers by electrospinning
    (Springer, 2012) Anandhan, S.; Ponprapakaran, K.; Senthil, T.; George, G.
    Polybenzimidazole (PBI), a high performance polymer, was synthesized from 3,3?-diaminobenzidine (DAB) and isophthalic acid (IPA) through polycondensation. The chemical structure of PBI was confirmed by Fourier transform infrared spectroscopy. Thermal characterization of PBI was done by thermogravimetry and differential scanning calorimetry. PBI nanofibers were fabricated by electrospinning of N, N-dimethyl acetamide solutions of PBI of different solution concentrations, at different voltages. The effects of solution and process parameters (namely, solution concentration and DC voltage) on morphology and average diameter of electrospun PBI fibers were investigated. The electrospun ultrafine fibers' diameter and morphology were characterized by using scanning electron microscopy. Nanofibers were obtained only from PBI solutions of concentrations 12 and 14 % (w/v). At concentrations of 8, 10, and 16 %, fibers could not be obtained. The process parameters were optimized by using the statistical tool, factorial or two-way ANOVA (analysis of variance), DOE (design of experiments) and the results indicate that the applied voltage and the interaction of voltage and solution concentration are influential in determining the diameter and morphology of the electrospun ultrathin PBI fibers. Electrospun PBI fibers, as small as 56 nm, could be successfully produced by using the right combination of solution concentration and spinning voltage. © 2012 Central Institute of Plastics Engineering & Technology.
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    Structural characterization of nano-crystalline Co3O4 ultra-fine fibers obtained by sol-gel electrospinning
    (2013) George, G.; Anandhan, S.
    In this paper, we report the obtention of ultrafine fibers of cobalt oxide (Co3O4) by combining electrospinning method with high-temperature calcinations from the precursor sol of poly(2-ethyl-2- oxazoline) (PEtOx)/cobalt acetate tetrahydrate [Co(CH3COO) 2·4H2O] in water. The optimum electrospinning conditions for obtaining precursor composite nanofibers from PEtOx/Co(CH 3COO)2·4H2O solution in water, to produce ceramic nanofibers, were studied. The average fiber diameter of the precursor composite fibers measured by scanning electron microscopy (SEM) was approximately 200 nm. Thermogravimetric analysis of PEtOx was performed to estimate the suitable calcination temperature of the precursor fibers. SEM images of the ceramic fibers obtained after calcination revealed the shrinkage in diameter due to complete degradation of the polymer and Co(CH 3COO)2·4H2O. Fourier transform infrared spectroscopy was used to ensure the complete pyrolysis of polymer during calcinations of the composite fibers. Crystalline properties of the ceramic fibers were studied by X-ray diffraction and high resolution transmission electron microscopy. The ceramic fibers are polycrystalline with an average grain size of ?40 nm obtained at a calcination temperature of 773 K. It was observed that the grain sizes increased as the calcination temperature was increased, due to self assembly mechanism. © 2013 Springer Science+Business Media New York.
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    Influence of nano-aluminum-hydroxide on tribological, mechanical and flammability properties of E-glass fabric/epoxy multi-layered laminates
    (Huthig GmbH, 2014) Shivamurty, B.; George, G.; Bhat, K.U.; Anandhan, S.
    E-glass fabric/nano aluminum hydroxide (ATH)/epoxy composites were prepared by manual lay-up and compression molding. An image processing tool was used to quantify fineness of dispersion of nano-ATH particles in epoxy. Fourier transform infrared (FTIR) spectroscopy was used to understand the interaction between nano-ATH and epoxy. Mechanical properties, sliding wear resistance and fire retardance of these composites improved upon addition of nano-ATH. The composite containing 0.125 wt% of nano-ATH exhibited optimum mechanical properties and low specific wear rate.
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    Glass fiber-supported NiO nanofiber webs for reduction of CO and hydrocarbon emissions from diesel engine exhaust
    (Cambridge University Press, 2014) George, G.; Anandhan, S.
    In this study, nickel acetate tetrahydrate (NACTH)/poly(styrene-co-acrylonitrile) (SAN) sol was used for the fabrication of nanocrystalline NiO nanofibers. An indigenous setup was developed to use these nanofibers for the oxidation of carbon monoxide (CO) and unburnt hydrocarbons (HC) from diesel engine exhaust. The morphological, compositional, and crystalline properties of the NiO nanofibers obtained after calcination were studied by scanning electron microscopy, Fourier transform infrared (FTIR) spectroscopy, and x-ray diffraction (XRD). Clear evidence of defects in the fibers was observed in ultraviolet-visible-near infrared (UV-Vis-NIR) spectra, Raman spectra, and magnetic property measurements. The NiO nanofiber mats supported by glass fiber mats were efficient in oxidizing CO and HC from diesel engine exhaust, and the maximum efficiency was achieved by using NiO nanofibers with the maximum amount of defects. © © Materials Research Society 2014.
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    Glass fiber-supported NiO nanofiber webs for reduction of CO and hydrocarbon emissions from diesel engine exhaust
    (Cambridge University Press, 2014) George, G.; Anandhan, S.
    In this study, nickel acetate tetrahydrate (NACTH)/poly(styrene-co-acrylonitrile) (SAN) sol was used for the fabrication of nanocrystalline NiO nanofibers. An indigenous setup was developed to use these nanofibers for the oxidation of carbon monoxide (CO) and unburnt hydrocarbons (HC) from diesel engine exhaust. The morphological, compositional, and crystalline properties of the NiO nanofibers obtained after calcination were studied by scanning electron microscopy, Fourier transform infrared (FTIR) spectroscopy, and x-ray diffraction (XRD). Clear evidence of defects in the fibers was observed in ultraviolet-visible-near infrared (UV-Vis-NIR) spectra, Raman spectra, and magnetic property measurements. The NiO nanofiber mats supported by glass fiber mats were efficient in oxidizing CO and HC from diesel engine exhaust, and the maximum efficiency was achieved by using NiO nanofibers with the maximum amount of defects. © © Materials Research Society 2014.
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    Structure-property relationship of sol-gel electrospun ZnO nanofibers developed for ammonia gas sensing
    (Academic Press Inc. apjcs@harcourt.com, 2014) Senthil, T.; Anandhan, S.
    Zinc oxide (ZnO) based nanomaterials have been used in various gas sensors due to the wide band gap (3.37. eV), large exciton binding energy and high mobility of charge carriers of ZnO. In this work, nanocrystalline ZnO nanofiber mats were synthesized through combined sol-gel electrospinning techniques followed by calcination, in which poly(styrene- co-acrylonitrile) and zinc acetate were used as the binder and precursor, respectively. Average diameter of the ZnO nanofibers decreased from 400 to 60. nm, while their grain size and crystallinity were enhanced by increasing the calcination temperature. Morphology and structure of the ZnO nanofiber mats were characterized by high resolution transmission electron microscopy, scanning electron microscopy, Fourier transform infrared spectroscopy and X-ray diffraction. ZnO nanofiber mats were found to be superhydrophilic (contact angle was close to 0°) by contact angle measurements. The sensitivity of these ZnO nanofibers in detecting gaseous ammonia was tested using an indigenous set up. Due to their high surface area and superhydrophility, these ZnO nanofiber mats were highly sensitive in sensing gaseous ammonia and the sensitivity of these mats increased as a function of their calcination temperatures. © 2014 Elsevier Inc.
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    Morphological and structural characterisation of sol-gel electrospun Co3O4 nanofibres and their electro-catalytic behaviour
    (Royal Society of Chemistry, 2015) George, G.; Elias, L.; Hegde, A.C.; Anandhan, S.
    Evolution of hydrogen and oxygen are a crucial part of many renewable energy systems. The replacement of the essential and expensive components in such systems can reduce the capital cost and improve the effectiveness of those systems. In this study, Co3O4 nanofibres were fabricated from sol-gel assisted electrospun poly(styrene-co-acrylonitrile)/cobalt acetate tetrahydrate precursor composite fibres. The morphological and compositional features of the Co3O4 nanofibres obtained after calcination of the precursor nanofibers were studied using scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy. The results of X-ray diffraction study and Raman spectroscopy revealed that the average grain size of the fibres increased with the calcination temperature. Clear evidence of defects in the fibres was observed in ultraviolet-visible-near infrared and energy dispersive spectroscopic measurements. The electrocatalytic behaviour of Co3O4 nanofibres obtained at different calcination temperatures was studied using them for the water splitting reaction in an alkaline medium. The maximum efficiency in the hydrogen evolution reaction was achieved using the Co3O4 nanofibres obtained at the lowest calcination temperature, which had the highest surface area and the smallest grain size. © The Royal Society of Chemistry 2015.
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    Interparticle interactions and lacunarity of mechano-chemically activated fly ash
    (Elsevier, 2015) Patil, A.G.; Shanmugharaj, A.M.; Anandhan, S.
    A class F fly ash was subjected to high-energy ball milling-induced mechano-chemical activation aided by a surfactant. The resultant nanostructured fly ash was characterized by various techniques. X-ray fluorescence results showed that the amount of iron oxide was reduced from 4.39% to 2.75% after pre-treatment of fly ash by magnetic separation. Ethyl acetate as the milling medium, a ball to powder ratio of 12:1 and 2wt% of surfactant reduced the average particle size of fly ash to 329nm and led to a specific surface area of 8.73m2/g. The decrease in crystallite size of mechano-chemically activated fly ash was confirmed from a reduction in peak intensity with a broadened amorphous phase by X-ray diffraction studies. X-ray photoelectron spectroscopic characterization illustrated that peak area of major elements (O, Si and Al) increased after milling. Morphological and FTIR studies revealed that the smooth and inert surface of the fly ash was converted to a rough and more reactive one after mechano-chemical activation. The surface modification of fly ash with the surfactant was determined from FTIR spectroscopy. Also, a fractal approach was used to characterize the lacunarity of the agglomerates in the nanostructured fly ash. © 2014 Elsevier B.V.
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    Thermodynamic miscibility and thermal and mechanical properties of poly(ethylene-co-vinyl acetate-co-carbon monoxide)/poly(vinyl chloride) blends
    (John Wiley and Sons Inc, 2015) SelvaKumar, M.; Mahendran, A.; Bhagabati, P.; Anandhan, S.
    This paper reports the miscibility and thermal and mechanical properties of solution cast binary blends of poly(ethylene-co-vinyl acetate-co-carbon monoxide) (EVACO) and poly(vinyl chloride) (PVC). The composition of these blends was varied from 10:90 to 90:10 of PVC/EVACO (w/w %). Fourier transform infrared spectroscopy revealed an extensive intermolecular attraction between the blend components, which accounts for their mutual solubility. The differential scanning calorimetry study revealed that the blend components are miscible with each other in all proportions as they exhibited a single glass transition temperature. Tensile strength, moduli, and thermal stabilities of these blends significantly improved with increasing proportion of PVC. © 2014 Wiley Periodicals, Inc.