Hydrophilic Nano Research Articles

Coating of graphite flakes with MgO/carbon nanocomposite via gas state reaction

Coating of graphite flakes with MgO/carbon nanocomposite was carried out via gaseous state reaction between mixture of Mg metal, CO gas and graphite flakes at 1000 °C. XRD and FE-SEM analysis of coating showed that the coating was comprised of MgO nano particles and amorphous carbon distributed smoothly and covered the graphite surface evenly. Thermodynamic calculations were employed to predict the reaction sequences as well as phase stability. The effect of coating on water wettability and oxidation resistance of graphite was studied using contact angle measurement and TG analysis, respectively. It was demonstrated that the reaction between Mg and CO could result in MgO/C nanocomposite deposition. The coating improved water wettability of graphite and also enhanced the oxidation resistance of graphite flakes significantly. Also the graphite coating showed significant phenolic resin-wettabilty owing to high surface area of such hydrophilic nano composite coating. The importance of graphite coating is explained with emphasis on its potential application in graphite containing refractories.

Preparation and characterization of biodegradable waterabsorbent PAN/SS nanocomposite

AbstractPolyacrylonitrile (PAN)/sodium silicate (SS) nanocomposite was prepared via nonconventional emulsion method using an in situ developed transition metal complex Cu(II)/glycine taking ammonium persulfate (APS) as initiator, with a novel motive of converting hydrophobic homopolymer PAN into hydrophilic nano material via nanotechnology by the inclusion of SS to the homopolymer. UV–visible spectral analysis was carried out which revealed various interactions between the in situ developed complex with other reaction components. The formation of the PAN/SS nanocomposite was confirmed by infrared spectra (IR). Furthermore, as evidenced by transmission electron microscopy (TEM), the composite so obtained was found to have nano scale structure. X‐ray diffraction (XRD) was carried out suggesting that the silicate layers were exfoliated during the polymerization process. An increase in the thermal stability for the developed nanocomposite was recorded by thermogravimetric analysis (TGA). Surprisingly, it was also found that the PAN/SS nanocomposite showed considerable amount of waterabsorbency and was biodegradable as tested by activated sludge and cultured media and further confirmed by scanning electron microscopy (SEM). POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers

Ceramic-Polymer Electrolytes for All-Solid-State Lithium Rechargeable Batteries

New polyurethane acrylate (PUA)-based nanoceramic-polymer electrolytes in a high ceramic filler content were examined in all-solid-state lithium-polymer cells (Li/PUA-/) and at 60°C. The composite electrolyte containing more than 20 wt % hydrophilic nano- enhanced its mechanical strength 600% compared to the ceramic-free electrolyte. The additions of nano- powders in a high concentration protected the electrode surfaces, improved greatly the interfacial stability between composite cathode and the electrolyte, and gave rise to a further reversible lithium stripping-deposition process. The cells showed good rate capacity and excellent cyclability. The discharge capacity kept 65% of initial capacity after 300 cycles with a coulombic efficiency approaching 100%. Capacity fading upon cycling was believed to be due to the increase of cell resistance during charge-discharge cycling. The cell self-charge loss at 60°C was extremely low about 0.05% per day.

Interfacial properties of nano TiO2 and cellulose paper coating

This paper examined different kinds of organic functional groups that were introduced onto the surface of nano TiO 2 by surface modification with different types of zircoaluminate coupling agents. The modified nanoTiO 2 products with different interfacial properties were obtained, and the impact of the interfacial properties of nanoTiO 2 on the rheological behavior of paper coating and the properties of coated paper was systematically investigated. The steady shear rheological results showed that the paper coatings containing nano TiO 2 exhibited a pseudoplastic fluid behavior, characterized as obvious shear thinning. Compared to the hydrophilic unmodified nano TiO 2 , modified nano TiO 2 could contribute more to the viscosity of paper coatings. The study on the dynamic viscoelasticity revealed that, through the enhancing action among each component in paper coatings, the modified nano TiO 2 with quaternary amine groups or carboxyl led to a higher dynamic elastic storage modulus and viscous loss modulus of paper coatings. In addition, SEM and AFM analyses indicated that adding modified nano TiO 2 products in paper coating could improve the coating structure, thus ameliorating the optical properties and printability of coated paper. The results obtained could provide a good reference for the application of nano pigments in paper coating.