DSpace Collection: 2008 Publications
http://localhost:8080/xmlui/handle/123456789/79
2008 Publications2024-03-29T02:57:27ZThermal degradation and crystallisation studies of reactively compatibilised polymer blends
http://localhost:8080/xmlui/handle/123456789/2132
Title: Thermal degradation and crystallisation studies of reactively compatibilised polymer blends
Authors: Jose, S; Thomas, S; Biju, P k; Peter Koshy; Karger-Kocsis, J
Abstract: The thermal degradation and crystallisation behaviours of polyamide12/isotactic polypropylene (PA12/PP) blends were studied. Effects of blend ratio and compatibiliser concentration on the thermal degradation properties of the blends were analysed. The activation energy for degradation in compatibilised and uncompatibilised blends computed using Horowitz-Metzger equation was reported. The blend ratio as well as the presence of compatibiliser has significant effect on the thermal stability of the blends. Phase morphology was found to be one of the decisive factors that affected the thermal stability of both uncompatibilised and compatibilised blends. Melting and crystallisation behaviours of the blends in the presence and absence of compatibiliser were evaluated. It was observed that blending has no significant effect on the melting and crystallisation properties of PA12 and PR Compatibilisation of 70/30 and 50/50 PA12/PP blends didn't affect the crystallisation and melting behaviours of PA12 and PP even though some discrepancies were observed.2008-01-01T00:00:00ZIonic conductivity in new perovskite type oxides: NaAZrMO(6) (A = Ca or Sr; M = Nb or Ta)
http://localhost:8080/xmlui/handle/123456789/2131
Title: Ionic conductivity in new perovskite type oxides: NaAZrMO(6) (A = Ca or Sr; M = Nb or Ta)
Authors: Deepthi, N R; Ravindran Nair, K; Prabhakar Rao, P; Sibi, K S; Peter Koshy; Vaidyan, V K
Abstract: New oxides of the type, NaAZrMO(6) (M = Ca or Sr; M = Nb or Ta), have been prepared by the solid-state reaction technique. Phase identification by powder X-ray diffraction (XRD) shows that NaCaZrMO6 has orthorhombic perovskite type structure (Pnma) and NaSrZrMO6 has cubic perovskite type structure (Pm3m). The grain morphology observation by scanning electron microscope (SEM) shows well-sintered grains. ac impedance spectra and electrical conductivity measurements in air, oxygen and nitrogen atmospheres indicate that they are probable oxide ion conductors with ionic conductivities of the order of 10(-3) S cm(-1) at 750 degrees C.2008-01-01T00:00:00ZDesign of two-dimensional biomimetic uranyl optrode and its application to the analysis of natural waters
http://localhost:8080/xmlui/handle/123456789/2130
Title: Design of two-dimensional biomimetic uranyl optrode and its application to the analysis of natural waters
Authors: James, D; Mary Gladis, J; Pandey, A K; Naidu, G R K; Prasada Rao, T
Abstract: A two-dimensional biomimetic optrode for the detection and quantification of uranium in natural waters was fabricated. The sensing element was designed by the inclusion of uranyl ion imprinted polymer particles into polymethyl methacrylate followed by casting a thin film on a glass slide without any plasticizer. The ion imprinted polymer material was prepared via covalent immobilization of the newly synthesised ligand 4-vinyl phenylazo-2-naphthol by thermal polymerization. Operational parameters such as pH, response time and the amount of sensing material were optimized. The response characteristics of the imprinted and the corresponding non-imprinted polymer inclusion optrodes of uranium were compared under optimum conditions. The imprinted polymer inclusion optrode responds linearly to uranium in the concentration range 0-1.0 mu g mL(-1) with a detection limit of 0.18 mu g mL(-1), which is much better than the solution studies using 4-vinyl phenylazo-2-naphthol (1.5 mu g mL(-1)). Triplicate determinations of 100 mu g of uranium(VI) present in 250 mL of solution gave a mean absorbance of 0.018 with a relative standard deviation of 8.33%. The superior sensitivity of imprinted polymer inclusion optrode is exemplified by lower detection limits and broader dynamic range over non-imprinted polymer inclusion optrode. The developed imprinted polymer inclusion optrode was found to give stable and precise response for 3 months and can be used without any loss in sensitivity. The applicability for analysing ground, lake and tap-water samples collected in the vicinity of uranium deposits was successfully demonstrated.2008-01-01T00:00:00ZNanostructural and surface morphological evolution of chemically sprayed SnO2 thin films
http://localhost:8080/xmlui/handle/123456789/2129
Title: Nanostructural and surface morphological evolution of chemically sprayed SnO2 thin films
Authors: Chacko, S; Philip, N S; Gopchandran, K G; Peter Koshy; Vaidyan, V K
Abstract: Physical properties of a nanocrystalline thin film is greatly influenced by its morphological and structural evolution. We try to understand the transition of SnO2 thin films from amorphous to nanocrystalline structure with XRD, IR, SEM, AFM and surface profiler studies. A 2D layer like structure resulting from quantum confinement is found for the films prepared at 400 degrees C. We observed a new IR band at 530 cm(-1) that was theoretically predicted and report it for the first time. A correlation of population of defects in SnO2 films with change in lattice parameters and FWHM of IR bands are reported. The electric and optical properties of the films have been discussed.2008-01-01T00:00:00Z