Faculty Publications
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Item Thermal degradation and swelling of thermoplastic vulcanizates from NBR/SAN and NBR/Scrap computer plastics blends(Huthig GmbH, 2009) Anandhan, S.; Rajeev, R.S.; De, S.K.; Bhowmick, A.K.Thermoplastic elastomeric blends of nitrile rubber (NBR)/poly(styrene- coacrylonitrile) (SAN) and NBR/scrap computer plastics (SCP) based on acrylonitrile-butadiene-styrene terpolymer (ABS) were prepared. Thermoplastic elastomeric blends of NBR/SAN containing various amounts of a model waste nitrile rubber powder (w-NBR) were also prepared. Thermogravimetric analysis of the above blends was performed in a nitrogen atmosphere. Both Friedman and Flynn-Wall-Ozawa methods were used for the evaluation of activation energies of thermal degradation of these blends. The dynamically vulcanised blends exhibit higher amount of activation energies for thermal degradation than the unvulcanised ones. Swelling studies were performed in various solvents having different solubility parameter values and maximum swelling was found to occur in a solvent having a solubility parameter that was closer to that of the blend components, i.e., around 20MPa1/2. Dynamically vulcan-ised blends show excellent resistance to IRM #903 oil as well as four chosen solvents possessing different solubility parameters (E).Item 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.Item 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.Item Synthesis and characterisation of nickel oxide nanofibre webs with alcohol sensing characteristics(Royal Society of Chemistry, 2014) George, G.; Anandhan, S.In this study, nickel oxide (NiO) nanofibres were obtained by a sol-gel electrospinning process followed by calcination from an aqueous sol of poly(2-ethyl-2-oxazoline)/nickel acetate tetrahydrate. Thermogravimetric analysis was used to determine the degradation temperature of the composite fibres, so as to get nickel oxide nanofibres. X-ray photoelectron spectroscopy and X-ray diffraction studies revealed the complete elimination of the organic phase from NiO fibres during calcination. The change in grain size with calcination temperature was determined by X-ray diffraction. The defects in fibres resulted in the modification of their Raman spectra as compared with that of a single crystal. The magnetic properties of the fibres were reduced as the calcination temperature was increased; this is due to the presence of non-stoichiometric defects. As the calcination temperature was increased, the amount of defects was reduced, which induced a difference in the band gap energy of the fibres. Sensitivity of the NiO fibres towards five different alcohols was studied, and the sensitivity towards ethanol was the highest. © The Royal Society of Chemistry 2014.Item Influence of organically modified clay mineral on domain structure and properties of segmented thermoplastic polyurethane elastomer(2014) Anandhan, S.; Lee, H.S.Segmented polyether-urethane/organically modified montmorillonite (O-MMT) nanocomposites were synthesized with poly(tetramethylene glycol) (PTMG), 4,4?-diphenylmethane diisocyanate (MDI), butane diol (BD), and a commercially available clay Cloisite-30B® (O-MMT). The state of dispersion of the clay crystals in the thermoplastic polyurethane elastomer (TPU) matrix was studied by X-ray diffraction and transmission electron microscopy (TEM). The phase-separated morphology of the TPU was revealed by high-resolution TEM (HRTEM) and atomic force microscopy (AFM). O-MMT caused a marginal increase in the glass transition temperature of the soft segments of the TPU and this increase is proportional to the amount of O-MMT in the nanocomposites. Differential scanning calorimetry (DSC) was employed to study the effect of O-MMT on the extent of phase separation in the TPU in these nanocomposites. Thermogravimetric analysis (TGA) results indicate a substantial improvement in the thermal stability of TPU by the addition of O-MMT. Tensile strength and elastic modulus are dramatically decreased by the incorporation of O-MMT into TPU, which is due to the hindrance of the phase-separation process by the exfoliated clay-layered crystals. © The Author(s) 2012 Reprints and permissions:sagepub.co.uk/journalsPermissions.nav.Item A high thermally stable polyacrylonitrile (PAN)-based gel polymer electrolyte for rechargeable Mg-ion battery(Springer, 2020) Singh, R.; Janakiraman, S.; Khalifa, M.; Anandhan, S.; Ghosh, S.; Adyam, A.; Biswas, K.The ionic conductivity and thermal stability of the electrolyte-separator system is an essential parameter for improving battery performance and safety. The present work addresses the high thermally stable gel polymer electrolyte (GPE) using polyacrylonitrile (PAN) as a polymer membrane and magnesium perchlorate in propylene carbonate (Mg(ClO4)2-PC) as a liquid electrolyte. The PAN based polymer membrane is prepared by electrospinning process which produces a bead free and uniformly distributed nanofibers. The electrospun PAN based GPE is characterized by different physical and electrochemical techniques like X-ray diffraction, field emission scanning electron microscopy, thermogravimetric analysis, differential scanning calorimetry, ionic conductivity, linear sweep voltammetry, magnesium ion transference number and electrochemical impedance spectroscopy. The ionic conductivity of PAN is 3.28 mS cm?1, compared to that of PP Celgard is 1.97 × 10–4 mS cm?1 at 30 °C. The electrochemical stability of PAN is 4.6 V and also exhibits excellent interfacial stability with magnesium metal. The results showed that the PAN-based GPE has higher ionic conductivity and thermal stability than the polypropylene (PP) Celgard membrane. © 2020, Springer Science+Business Media, LLC, part of Springer Nature.Item Thermal and Flammability Properties of Glass Fabric/MWCNT/Epoxy Multilayered Laminates(Korean Institute of Electrical and Electronic Material Engineers, 2021) Shivamurty, B.; Anandhan, S.; Bhat, K.U.; Thimmappa, B.H.S.Multiwalled Carbon Nano Tube (MWCNT) filled glass fabric reinforced epoxy composites (MWCNT/GEC), and neat GEC were prepared by hand-lay-up followed by hot compression molding method. As per the ASTM standard, specimens were prepared and investigated the influence of the addition of MWCNTs on flammability properties of GEC through the UL-94 vertical flammability test and the limiting oxygen index (LOI) method. The thermal degradation was studied by thermogravimetric analysis (TGA). It was found that the GEC improved upon the thermal stability and fire-retardant properties due to the addition of MWCNTs. It was observed that the 0.3 wt.% MWCNTs-glass fabric reinforced epoxy composite (0.3MWCNT/GEC) exhibits better properties than neat GEC and 0.075 wt.% MWCNT-glass fabric reinforced epoxy composite (0.075MWCNT/GEC) and 0.15 wt.% MWCNT-glass fabric reinforced epoxy composites (0.15MWCNT/GEC). Hence, this material may be suitable for electrical devices and appliances based on the other required properties’ further fulfillment. © 2021, The Korean Institute of Electrical and Electronic Material Engineers.