Current Application of Polymers and Nano Materials

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Authors: Natarajan Senthilkumar, Mohammad Luqman
Abstract: The combination of the concept of metallopolymers with urethane chemistry offers a versatile approach for the synthesis of new polyurethane materials. Polyurethanes are a distinct class of materials with tremendous industrial importance, and it is of interest to develop these materials with modified thermal and liquid crystalline behavior for advanced applications. Generally, polyurethanes suffer a major disadvantage of poor thermal stability. This can be improved upon by chemical modification of their structures by the incorporation of thermally stable heterocyclic ring structures along with transition metals. Metal-containing polyurethanes prepared from a polymeric diol, diisocyanate and a metal containing diol (metallodiol and metallomesogenic diol) as a chain extender are attracting contemporary research interest. The addition of a polymeric diol (polyol) induces flexibility to the polyurethane by reducing the glass transition temperature, increases its solubility and imparts elastomeric properties. Multifunctional polymers are materials poised for applications in different avenues with preference for plastic electronics. An introduction-cum-overview of synthesis and applications of metal-containing polyurethanes is presented in this chapter.
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Authors: Mahesh Padaki, Chitrakar Hegde, Arun Mohan Isloor
Abstract: In the recent years membrane technology has gained significant attention from polymer chemists all around the world due to their attractive features such as efficiency, low costs, low energy costs and as effective solutions to longstanding problems in the chemical industries. Membrane technologies have been widely applied in the separation of liquids and even gases. Many separation problems can be solved economically by nanofiltration alone or in combination with other separation processes. This study aimed to synthesize polysulfone based nanofiltration membranes using DIPS (diffusion induced phase separation) technique. Newly synthesized polymer membranes were subjected to Infra red spectral and water uptake studies. Membranes were also characterized using electrochemical spectroscopy for their proton conducting property. Their surface morphology is visualized by SEM.
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Authors: Asif A. Qaiser, Margaret M. Hyland
Abstract: X-ray photoelectron spectroscopy (XPS) is a promising technique employed for the study of conducting polymers and their composites. XPS was used to study the surface chemistry of polyaniline-mixed cellulose ester (PANI-ME) composite membranes prepared by various chemical oxidative polymerization techniques such as insitu solution, vapour phase polymerizations and aniline polymerization using a two-compartment permeation cell. Hydrolytic degradation of surface deposited PANI and scission of cellulosic chains due to x-ray irradiation inside the XPS chamber influenced the quantification of polyaniline deposition levels as well as oxidation and doping states in PANI-ME membranes. N1s core level spectra allowed characterization of the PANI deposition level, its oxidation state and x-ray induced cellulosic ring cleavage. C1s and O1s core level spectra revealed PANI hydrolysis at the membrane surface. These degradation phenomena influence the performance of PANI composite membranes used specifically in electrodiffusion applications. It was shown that successful quantification of PANI deposition levels and its oxidation state on microporous mixed cellulose ester membranes using XPS could be realized by incorporating the degradation effects in the characterization results.
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Authors: M.G. Manjunatha, Airody Vasudeva Adhikari, Pramod Kumar Hegde
Abstract: A new donor-acceptor type poly[3-{5-[3,4-didecyloxy-5-(1,3,4-oxadiazol-2-yl)thiophen-2-yl]-1,3,4-oxadiazol-2-yl}-9-dodecyl-9H-carbazole] (P) has been synthesized starting from thiodiglycolic acid and 9H-carbazole through multistep reactions. The polymer has been synthesized through precursor polyhydrazide route. The weight average molecular weight of the polymer was found to be 7210. The polymer exhibited intense green fluorescence in solid sate. Cyclic voltammetric experiments showed that the polymer has low-lying LUMO (-3.55 eV) and high lying HOMO (-5.77 eV) energy levels due to the presence of alternate donor and acceptor units. The optical and electrochemical studies reveal that the new polymer (P) is a promising material for the development of polymer light emitting diodes (PLEDs).
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Authors: Pramod Kumar Hegde, Airody Vasudeva Adhikari, M.G. Manjunatha, C.S. Suchand Sandeep, Philip Reji
Abstract: Measurements of nonlinear optical properties of a newly synthesized thiophene based polymer are reported. The nonlinear transmission measurements were performed on the polymer dissolved in N,N-dimethylformamide by employing the single beam Z-scan technique using a Q-switched laser output at 532-nm. The polymer shows strong optical limiting behavior, where the transmittance decreases when the pump fluence is increased. It was found that an effective three-photon absorption (3PA) model at the excitation wavelength gives the best fit to the obtained experimental data. The value of the 3PA coefficient has been numerically calculated. This study clearly reveals the potential of new polymeric material has, for optical limiting applications.
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Authors: Rajesh J. Tayade, D.L. Key
Abstract: TiO2 derived nanotubes were prepared by hydrothermal treatment of TiO2 (anatase) powder in 10 M NaOH aqueous solution. The crystalline structure, band gap, and morphology of the TiO2 nanotubes were determined by X-ray diffraction (XRD), diffuse reflectance spectroscopy (DRS), scanning electron microscopy (SEM), Transmission Electron microscopy (TEM) and N2 adsorption (BET) at 77 K, respectively. It was observed that the surface area of the nanotubes was increased twelve times compared with TiO2 (anatase) powder. The results demonstrated that the photocatalytic activity of TiO2 nanotubes was higher than that of TiO2 (anatase) powder. The photocatalytic activity of the nanotubes was evaluated in presence of sunlight by degradation of aqueous nitrobenzene. Complete degradation of nitrobenzene was obtained in 4 hours using TiO2 nanotubes whereas 85% degradation was observed in case of TiO2 (anatase).
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Authors: Jaya Rawat, Saptarshi Ray, P.V.C. Rao, Nettem V. Choudary
Abstract: Biofouling prevention remains a major challenge to the chemists, and researchers around the world who are engaged in the development of antifouling paints that can prevent growth of organisms like barnacles, algae and tubeworms on the submerged structures. Growth of organisms on the surfaces exposed to marine and freshwater environment not only reduces the efficiency of such structures, e.g. reduction of heat transfer etc, but also causes structural damages. In order to prevent the growth of organisms on surfaces of the marine and freshwater environments, coatings containing biocides are generally used. However, use of biocides not only leads to the corrosion of the metallic structures in some cases, but it also inflicts severe damage to the aquatic ecosystem. It is thus necessary to develop anti-biofouling paints that are innocuous to both the environment and the structures. One alternative approach may be incorporation of nanoparticles, and preventing bacterial bio-film formation as well as the attachment of larger organisms. Various nanoparticles of metal and their oxides have been recognized to possess antibacterial properties. The development of such materials is a challenge to both the chemist and the biologist, where effective choice of methods that provide relevant information regarding application of the metal nanoparticles in anti-fouling materials, becomes the central objective. The present article is a short review in the area of nanoparticle doped antifouling paints. In addition, some aspects covering our experimental results on the selected bio-fouling paints with dispersed nanoparticles of ZnO, CuO, Al2O3, MgO, TiO2 and Co3O4. It also discusses the techniques used for the characterization of the nanoparticle-doped materials and methods for the determination of their efficacy against bio-film formation.
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Authors: Sriram Venkataramani, Tharanikkarasu Kannan
Abstract: A novel single-site catalyst was prepared from N-pheneyldiethanolamine and titanium tetrachloride and characterized using spectroscopic methods such as Nuclear Magnetic Resonance (NMR) spectroscopy and Infra Red (IR) spectroscopy. It was prepared insitu and used to polymerize ethylene along with methylaluminoxane (MAO) as co-catalyst. The turnover frequency for ethylene polymerization was found to be 350 g and 550g polymer/mol catalyst/h for 1 bar and at 2 bar respectively. As the turn over frequency at the studied reaction conditions is good, the present N-pheneyldiethanolamine-based catalyst is a good single-site catalyst for olefin polymerization
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