Browsing by Author "Mantilaka, M.M.M.G.P.G."

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    Carbon Fiber Networked Nano Carbon Black as a Novel Conductive Filler to Enhance the Thermal Conductivity of Natural Rubber Composites
    (Uva Wellassa University of Sri Lanka, 2018) Jayasinghe, J.M.A.R.B.; De Silva, R. T.; de Silva, K.M.N.; De Silva, W.R.M; Mantilaka, M.M.M.G.P.G.
    Thermal conductivity of natural rubber (NR) was enhanced by incorporating a novel conductive hybrid nano filler, namely carbon fiber (CF) networked spherical carbon black (CB) nanoparticles. The CF/CB hybrid fillers were artificially generated insitu in the rubber matrix by means of melt mixing, where the carbon black nanoparticles initially dispersed in natural rubber matrix with aid of rubber processing oil (polycyclic aromatic oil (PCA)) and hereafter, it was added CF to interconnect the CB domains. The preparation of master batch and final batch were done through the melt mixing in internal mixture where CF/CB total filler loading was kept at 40 parts per hundred of rubber (phr). Thermal conductivity of prepared composites were measured using lees disc method and the value of CF/CB rubber composite was 0.45 Wm-1K -1 and it was significantly improved compared to the control (0.25 Wm-1K -1 ). The neat carbon black (CB) composite was also prepared (at 40 phr) for comparison purposes and the thermal conductivity value deemed to be 0.35 Win-1K -1 . The higher conductivity of CF/CB composite suggests that the presence of CF network within CB nanoparticles has significantly contributed to enhance the thermal conductivity compared to that of the neat CB rubber composite. Thermal stability of the prepared CF/CB composites were enhanced significantly compared to control and the neat CB composite. Scanning electron micro photo graphs confirmed the generated network of CF onto the spherical CB nanoparticles and interconnected morphology of CF/CB hybrid fillers. The enhanced thermal conductivity of the compounds can be related to produce industrial applications such as tyres. Keywords: Natural rubber nanocomposites, Thermal conductivity, Carbon fibers, Carbon black
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    Nano-Porous Iron Yttrium Oxide Particles Synthesis as Value Addition to Sri Lankan Garnet Sand
    (Uva Wellassa University of Sri Lanka, 2018) Dissanayake, D.M.S.N.; Senthilnathan, Anoja; Chandrakumara, G. T. D.; Mantilaka, M.M.M.G.P.G.
    Garnet sand is a variety of mineral sands which is widely distributed in the southern coastal line of Sri Lanka with large minable quantities. However, these sands have limitedly use in industries, and more applications and products should be studied. In this study, natural garnet sand, which was collected from Pulmoddai, Sri Lanka was used to synthesize nanoporous iron yttrium oxide nanoparticles as it has wide range of applications such as magnetic nanofilters and nanoabrasives. The X-Ray diffraction (XRD) analysis revealed that the garnet sand consists of almandine variety (Fe3Al2Si303). First, 5.000 g of powdered garnet sand was refluxed with 60 ml of 10 M HCI solution at 90 °C. The digested solution was filtered and 2 % NaOH was added dropwise to the filterate until the pH becomes 14 in order to precipitate iron hydroxide and heated at 80 °C to dissolve hydrated aluminium. Then, the dry precipitate was dissolved in 10 M HNO3 and mixed with yttrium hexahydrate trinitrate solution. Later, the mixture was mixed with citric acid and pH was controlled to 2 using aqueous ammonia. The solution was heated at 80 °C until a light brown xerogel is formed. Finally, the xerogel was calcined at 800 °C for 5 h. Synthesized nanoparticles were characterized by XRD, Fourier Transform Infrared (FT-IR) spectroscopy and Scanning Electron Microscopy (SEM) techniques. The SEM data revealed the nano-porous structure with 100 rim pore size, while FT-IR and XRD results confirmed the FeYO3 composition of the nanomaterial. This work can be extended to study the dye adsorption of the iron yttrium oxide nanoparticles, encapsulation of the nanoparticles in the porous structure of synthesized particles and its potential applications, its magnetic property and enhancing the filteration property of the particles. Keywords : Garnet, Sand, Yittrium Iron Garnrt, Nanoporous
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    Synthesis of Feldspar Nanoparticles by Top Down Approach
    (Uva Wellassa University of Sri Lanka, 2018) Senthilnathan, Anoja; Dissanayake, D.M. S.N.; Palihawadana, T.C.; Wijesena, Ruchira N.; Tissera, Nadeeka D.; Mantilaka, M.M.M.G.P.G.
    Feldspars are group of rock forming tectosilicates that found as deposits mainly in central part of Sri Lanka such as Owala Rattota and Matale. Feldspars are used for the industrial purposes such as, ceramic tiles, glazes, glass industry, filler, welding electrodes and abrasives, due to their durability and resistance to chemical corrosion in the macrometer-range. However to the best of our knowledge, there is no reported studies related to synthesis of feldspar nanoparticles which have potential applications in different industrial applications. Usually, materials show different properties in nanometer scale such a thermally stability and Infrared Radiation Absorbance. In this study, we have synthesized nanoparticles of feldspar using a top down approach. Sri Lankan feldspar samples were collected, powdered up to micro meter range using ball mill and further reduced its particle size following two step process of nano-grinding, such that dry grinding and wet grinding using 0.6 mm tungsten carbide balls for 1 h each. The prepared particles were characterized by scanning electron microscopy (SEM), X- ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR). Mineralogical analysis using X-ray diffraction (XRD) show that the product feldspar samples are composed of mainly of pottassium oxides and silica oxides with minor aluminium. The particle sizes are in the range of nanometer scale and the average particle size is around 50 nm. The composition of these nanoparticles are proved not to be changing from the original composition as the XRD and FT-IR suggests. When coming down into nanoscale from a higher particle size, some property enhancements can be acquired. Typically, feldspar reflects UV light and absorbs some IR wavelengths. So this property can be applied as a potential application for textile and construction industries using the properties of these nano-feldspar. Keywords: Feldspar, Infrared radiation reflectance, Top down approach, Orthoclase, Filler