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Journal of Social Sciences

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This is an Open Access Journal

Open Access journal
ISSN (Print) 1549-3652
Published by Science Publications

[28 journals]

Low temperature oxygen plasma assisted surface modification of raw silk fibre and their characterizations
- Abstract: Abstract Raw silk fibre was treated with low temperature oxygen plasma with an aim to improve its dyeability. The XRD study reveals that a fraction of the macromolecules on the surface and in the inner part of silk fibres are oxidized during plasma treatment. The overall crystallinity of the fibre surface is reduced and the short range order is increased. Plasma treated fibre showed gradual increase of peak intensity in the Raman spectrum, and the peak shifts to lower wave numbers. Change in the micro-structural properties was observed in the scanning electron microscope images but the mechanical property of silk fibre was found to be insignificant. Smooth and homogeneous coating of a natural dye extracted from the Indian mulberry (Morinda citrifolia) was observed in the case of plasma-etched silk fibre.
  PubDate: 2013-03-19
Sisal fiber (SF) reinforced recycled polypropylene (RPP) composites
- Abstract: Abstract The article focuses on the effect of fiber surface treatment on the properties and performance of sisal fiber (SF) reinforced recycled polypropylene (RPP) composites. Sisal fiber was functionalized using different surface modification methods using silane (Si), glycidyl methacrylate (GMA) and o-hydroxybenzene diazonium chloride (OBDC) in order to improve the compatibility with matrix polymer. The experimental results revealed an improvement in the tensile strength to the tune of 11 %, 20 % and 31.36 % and impact strength to 78.72 %, 77 % and 81 % for silane, GMA and OBDC treated SF reinforced RPP composites, respectively as compared to RPP. Thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and heat deflection temperature (HDT) studies revealed enhanced thermal stability of RPP after SF reinforcement. The flammability behavior of surface modified SF/RPP composites were also investigated using horizontal burning method. Improved surface interaction between fiber and polymer matrix was confirmed from scanning electron micrographs (SEM).
  PubDate: 2012-12-01
Parametric study of manufacturing ultrafine polybenzimidazole fibers by electrospinning
- Abstract: Abstract 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.
  PubDate: 2012-12-01
Quality control and design optimisation of plastic product using Taguchi method: a comprehensive review
- Abstract: Abstract The Taguchi method is a powerful approach for solving quality problems in various aspects of the engineering field. Due to the increase of plastic parts consumption in each day, continuing customer satisfaction and economic viability in a competitive plastic industry environment are gaining tremendous attention. Thus, Taguchi method offers a simple yet systematic approach to optimize design for performance, enhancing the product quality and reduce the cost as well. A lot of studies have been conducted on the efficiency of this method. However a total comprehensive review of the implementation of the Taguchi method particularly in the plastic industry is limited. This paper presents an extensive review of past literature on the application of the Taguchi method in plastic industries focusing on product quality enhancing and obtaining the desired properties for new materials. From the review, it can be concluded that the Taguchi method has made extensive contribution to the plastic industry by bringing focused and awareness to robustness to improving quality.
  PubDate: 2012-12-01
Synthesis, optimization, characterization and agricultural field evaluation of polymer hydrogel composites based on poly acrylic acid and micro-fiber of oil palm empty fruit bunch
- Abstract: Abstract The optimum content of initiator (APS), cross linker (MBA), sodium hydroxide (NaOH) and oil palm empty fruit bunch micro-fiber (OPEFB), were optimized using central composite design method (CCD). Polymer hydrogel composite (PHGC) and plain polymer hydrogel (PHG) were characterized using thermogravimetric analysis (TGA), Fourier transform infrared (FTIR) and scanning electron microscopy (SEM). The influence of OPEFB on biodegradation of PHG was studied. The effect of polymer hydrogel composite (PHGC) on the holding capacity of sandy soil, urea leaching loss rate (ULLR) and okra plant growth were investigated. Statistical analysis of CCD showed a significant model and the highest absorption capacity recorded at 1.53–1.57, 14.24–14.42 and 12.88–12,97 % content for APS, NaOH and OPEFB respectively and 0.16 % for MBA. Biodegradation and thermal stability of PAA hydrogel were enhanced when OPEFB fiber was used. PHGC had a remarkable effect on the holding capacity of sandy soil, ULLR and the growth of okra plants.
  PubDate: 2012-12-01
Synthesis, spectral, magnetic, thermal and biological aspects of pyromellitic dianhydride based co-ordination polymers
- Abstract: Abstract A ligand, 2, 5-bis (4-nitrophenylcarbamoyl) terephthalic acid (bnpctpa) was synthesized by using dianhydride of 1, 2, 4, 5-benzenetetracarboxylic (pyromellitic dianhydride–abbreviated PMDA) with 4-nitro aniline. Novel Co-ordination polymers of this bis-ligand were prepared with Cu(II), Ni(II), Co(II), Mn(II) and Zn(II) metal salts. The co-ordination polymers and parent ligand were characterized by elemental analysis, spectral studies, thermogravimetry, number-average molecular weights (Mn), diffuse reflectance spectral studies and magnetic susceptibilities. The biological activity of all the samples has also been monitored against plant pathogens.
  PubDate: 2012-12-01
Optimisation of processing conditions of PP/HDPE/nano kaolinite clay composites by response surface methodology
- Abstract: Abstract Polypropylene (PP) and High density poly ethylene (HDPE) are widely used commodity plastics. A selected blend of PP and HDPE was reinforced with organo modified nanokaolin clay. The mechanical properties of the blend were modelled using Design of Experiments (DoE). A Box-Behnken design of Response Surface Methodology with four factors and three levels was used to model the relationship between the mechanical properties and the process parameters. The variables selected for the design are mixing temperature, mixing torque, mixing time and nanoclay loading. The nanocomposites were evaluated for tensile strength, tensile modulus, flexural strength, flexural modulus, impact strength and elongation at break. Morphological characterisation of the composites was done using X ray diffraction (XRD) and scanning electron microscopy (SEM) to substantiate the results. The model equations were used to generate response surfaces and contour plots for investigating the effect of processing parameters and nanoclay loading on mechanical properties of the nanocomposites and is validated. The main effects and interaction plots picture the effect of each variable and their combined effect on the mechanical properties of nanocomposites. The optimisation of parameters for all the properties is done to maximise the performance of nanocomposites. The results prove that nanoclay is a low cost and effective modifier for PP-HDPE blend.
  PubDate: 2012-12-01
Combustible gases from thermal plasma treatment of plastic waste with special reference to mobile phone waste
- Abstract: Abstract Recently disposal and recycle of mobile phone becomes a significant problem throughout the world. Primordial recycling or disposal of mobile phone waste to landfills and incinerators causes irreversible environmental damage by polluting water and soil, and contaminating air. The disposal of mobile phones thus requires to be considered in an effective, economical and environmental friendly way. The present work describes the treatment of mobile phone waste by thermal plasma under reducing condition. Combustible reformed gas (CO, H2 and hydrocarbons) having high calorific value was recovered. Generation of hydrogen gas and hydrocarbons are from the plastic part (whose major elements are carbon and hydrogen with some trace elements like oxygen and nitrogen) of the mobile phone waste. CO2 generation is almost below the detection limit. No significant other toxic gases such as NOx and H2S were observed. For better understanding of treatment under reduced condition, experiments have also been done under argon-air gas mixture condition without mobile phone waste. The present investigation provides an option for energy recovery with volume reduction, reduction of toxic gases and potential recovery of precious metals present in the mobile phone waste.
  PubDate: 2012-12-01
Effects of various EC plasticizer concentrations on salted PEO based solid polymer electrolytes
- Abstract: Abstract In this research, various weight percent of EC plasticizer are incorporated into salted PEO based polymer electrolyte system. Thin film electrolytes are prepared via solution casting technique and characterized by FTIR, XRD and DSC analysis in order to study their complex behaviour. The amorphicity of the electrolytes are measured by DC Impedance. The results reveal that the conductivity increases with increasing temperature when the EC plasticizer concentration increases up to 15 wt%. The temperature conductivity studies for 15 wt%. of EC plasticizer decrease due to displacement of the host polymer by plasticizer molecules within the salt complexes. Thus, it will decrease in ionic mobility. XRD studies reveal that the phase changes from crystalline to amorphous when EC plasticizer concentration increases. DSC studies indicate a decrease in Tm with increasing EC plasticizer concentration. Finally, the complexation process is examined using FTIR.
  PubDate: 2012-12-01
A simulation study on thermal conductivity of glass bead embedded polymeric system
- Abstract: Abstract A numerical simulation of the heat-transfer process within epoxy matrix composites filled with solid glass beads (SGB) is made by using finite element analysis (FEA). A commercially available finite-element package ANSYS is used for this numerical analysis. Three-dimensional spheres-in-cube lattice array models are constructed to simulate the microstructure of composite materials for various SGB content ranging from about 1 to 18 vol.% and the effective thermal conductivities (Keff) of the composites are estimated. The results show that the FEA simulated effective thermal conductivity decreases almost in a parabolic manner with increase in the volume fraction of the SGB fillers in the composites. Finally, the simulations are compared with measured Keff values obtained from experiments. Guarded heat flow meter test method is used employing the instrument Unitherm™ Model 2022 as per ASTM-E1530 to measure the thermal conductivity of these composites fabricated by hand layup technique. This study shows that the incorporation of SGB results in reduction of heat conductivity of epoxy resin and thereby improves its thermal insulation capability. The experimentally measured conductivity values are compared with the numerically calculated ones and it is found that FEA simulations are fairly close to the measured Keff.
  PubDate: 2012-06-01
Fracture study of modified TiO₂ reinforced PP/EPDM composite: mechanical behavior and effect of compatibilization
- Abstract: Abstract Elastomer-rich thermoplastic polyolefin containing Polypropylene(PP) and Ethylene-Propylene-Diene Terpolymer (EPDM) were studied with a variable EPDM content(0–50 %) in PP. Surface modification of TiO2 was made by using Amino Propyl Trimethoxy Silane APS and Triethyl Amine as coulping agent and surface grafting catalyst respectively with constant stirring at 300 rpm. PP/EPDM/TiO2 ternary composites were obtained after surface modification using twin screw extruder at TiO2 loading of 1 wt.%, 3 wt.% and 5 wt.% respectively using twin screw extruder and optimized. The effect of TiO2 nanoparticle on the mechanical and morphological properties was investigated, which showed improved impact strength and toughness under plane strain condition. Deep fracture study was done at different temperature (−60 to 60 °C) using izod impact test and SENT Test. Fracture stress, fracture energies and brittle to ductile transitions were determined by crack initiation and propagation process which shows that there is a significant increment in the impact and fracture energies at positive temperature. The morphological study of fractured surface of blend and blend nanocomposite has also been investigated employing SEM analysis.
  PubDate: 2012-06-01
Preparation and studying properties of thermoplastic starch/acrylonitrile–butadiene–styrene blend
- Abstract: Abstract In this work, blends of acrylonitrile–butadiene–styrene (ABS) and thermoplastic starch (TPS) were prepared by using a single screw extruder (SSE), the starch was plasticized in the single screw extruder by using glycerol as a plasticizer. The blends were characterized by studying rheological and mechanical properties. The rheological results indicated that ABS/TPS blend melts were pseudo plastic and exhibited shear–thinning behavior, and the viscosity of the blend decreased with increasing glycerol content. Also the values of flow activation energy at a constant shear stress (E τ ) of ABS1/TPS25G blend were determined, and it was found that E τ increased with increasing shear stress. Die swell measurements of the blend showed that die swell ratio increases with increasing shear stress and glycerol content in the blend, while it decreases with increasing L/R. Mechanical results showed that, the values of stress at break and strain at break decreased with increasing TPS content in the blend, which was attributed to the immiscibility between TPS and ABS.
  PubDate: 2012-06-01
Influence of blending functional polymers and radiation synthesized copolymers on the recycling of poly(ethylene terephthalate)
- Abstract: Abstract As a method of recycling, post-consumer waste poly(ethylene terephthalate) (WPET) was upgraded through blending with low ratios (5–10 %) of poly(ethylene glycol) (PEG), poly(methyl methacrylate) (PMMA), hydroxyethyl cellulose (HEC). WPET was also blended with radiation synthesized copolymers based on maleic anhydride (MAN) with methyl methacrylate (MMA), styrene (Sty) and vinyl acetate (VAc) monomers. The thermal stability of the different WPET blends was evaluated by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC), whereas the dyeability of the different WPET blends was evaluated by dyeing with the classic disperse and basic dyes. The results showed that the blending of WPET with polymers or copolymers ended with modified blends with improved thermal stability and dyeability with basic and disperse dyes compared to non-treated WPET. In this regard, the colour intensity of WPET blended with 10 % of PMMA polymer and MAN/VAc copolymer and dyed with the disperse dye was increased by 74% and 57 %, respectively. For the same blends but dyed with basic dyes, the colour intensity was increased by 483% and 733 %, respectively. Based on the results achieved, it can be concluded that the blending of WPET with pure polymers or copolymers may be considered a practical method of waste PET recycling.
  PubDate: 2012-06-01
Utilization of soya-based polyol for High solid PU-coating application
- Abstract: Abstract Soyabean oil is one of the most abundant and low-cost vegetable oils available in most parts of the world. In presence study, Novel polyester polyols were prepared physically blending from Soya phosphate ester polyol (SOPEP) and Soyabean oil based monoglyceride. High solids polyurethane (PU) coating formulations were developed by reacting novel polyester polyols with aromatic as well as aliphatic isocyanate adducts in different NCO/OH ratios. Structure of polyurethane resins was confirmed by FT-IR spectroscopy. The polyurethane resins were coated on test panels and tested for their flexibility, scratch hardness, cross-hatch adhesion, impact hardness, pencil hardness and solvent resistance as per standards. Thermal stability of these polymers was determined by thermogravimetric analysis (TGA).
  PubDate: 2012-06-01
Viscometric and light scattering investigation of the hydrogen bonds in the solutions of policarbinol
- Abstract: Abstract The nature of hydrogen bonding in methanol solutions of Policarbinol was investigated by the methods of Viscometry and Light scattering. The intrinsic viscosity (η) of narrow fraction of Policarbinol in methanol in presence of various amounts of hydrogen bond acceptor—sodium hydroxide (NaOH) was determined using Viscometry. It was established that the values of with addition of are passing through the extreme values due to the fact that intermolecular hydrogen bonds are broken first resulting in the decrease of, and then break in intramolecular hydrogen bonds is leading to increase of . Huggins constant reaches maximum value at complete suppression of intermolecular hydrogen bonds. Results of Light scattering show that the addition of an acceptor hydrogen bonds decreases the mean-square radii of gyration symbatically to values. The most compact size of macromolecules corresponds to minimum of values.
  PubDate: 2012-06-01
Development of novel pectin based membranes as proton conducting material
- Abstract: Abstract This work reports the synthesis and characterization of modified pectin based polymer electrolyte membranes crossilnked with glutaraldehyde (GA). The prepared diethanolamine modified pectin (DAP) membranes were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction analysis (XRD), methanol permeability and impedance spectroscopy. FTIR spectroscopic investigation indicates the presence of secondary amide absorption bands in the developed polymer electrolyte membranes. X-ray analysis reveals considerable improvement in the crystallinity of the electrolyte membranes after modification. The methanol permeability measurement confirms the lower methanol cross-over through the developed DAP membranes. A maximum room temperature proton conductivity of 2.536 × 10−2 was obtained for the membrane, which was designated as DAP-4. These properties make them good candidates for low cost biopolymer electrolyte membranes for fuel cell applications.
  PubDate: 2012-06-01
Fully biodegradable potato starch composites: effect of macro and nano fiber reinforcement on mechanical, thermal and water-sorption characteristics
- Abstract: Abstract Nature provides an impressive array of polymers which are generally biodegradable, as biodegradation is part of the natural biogeochemical cycle. Natural polymers, such as starch and cellulose have the potential to replace many current polymers if new material composites can be prepared to rival the performance of exisitng composites. While the conventional composites offer excllent mechanical properties and durability, most commercial polymers are derived from petroleum feed stock. Even though the utilization of petroleum-based composites are non-biodegradable and environmentally undesirable. Environment-friendly “Green” composites, based on potato starch and reinforced with nanocellulose/ramie fabric were prepared by hot compression moulding technique. PCL was coated to reduce water sensitivity. In the absence of reinforcing fillers, residual thermal stress transfer is affected. For reinforced composites, mechanical properties were seen to increase as a result of reinforcement. In composites containing the hydrophilic nanofibres and the hydrophobic PCL, phase inhomogeneity causes lower mechanical properties. Elongation at break increased for multiphase composites due to low interfacial adhesion. The uniform web-like network of nanofibres decreases water sorption. However, the presence of hydrophilic lignocellulosics increases water sorption. The PCL- containing composites show a low water sensitivity as expected. The nanostructure of the composites were analysed using TEM studies. A detailed investigation on the thermal properties of the thermoplastic potato starch were done by thermogravimetric analysis and flammability studies were done by limiting oxygen index analysis. The starch polymer is almost stable up to 300 °C. Also they showed better flame retardant properties.
  PubDate: 2012-06-01
Modeling of the mechanical properties of polylactic acid/clay nanocomposites using composite theories
- Abstract: Abstract The mechanical properties of polylactic acid (PLA)/nanoclay were examined using the composite theories. Among Guth equation, Halpin-Tsai Equation and Modified Halpin-Tsai equation, the Halpin-Tsai equation is universally used for composites reinforced by fiber-like or rod-like fillers. A brief comparison made for the Young’s modulus of the platelet-like fillers between the theoretical and experimental data. The experimental procedure followed for the determination of the aspect ratio statistically through the analysis of transmission electron microscope (TEM). The modulus reduction factor (MRF) is more significant towards the improvement of predicted theoretical values of the modulus. By introducing the modulus reduction factor (MRF) the polymer-clay nanocomposites was better explained through the composite theory.
  PubDate: 2011-12-01
SPSEBS/H₃PO₄ composite electrolyte membranes for application in PEMFC and DMFC
- Abstract: Abstract High proton conducting composite electrolyte membranes based on Sulfonated Poly Styrene Ethylene Butylene Poly Styrene (SPSEBS)/Phosphoric acid (2, 4, 6, 8 and 10 % H3PO4) composites were prepared. Their water and alcohol absorption increased with increase in H3PO4 content. The membranes were stable to aging in boiling water for 8 h. Their thermal stability was also improved. The ion-exchange capacity as well as the proton conductivity of composites increased significantly with the increase in the content of H3PO4. The proton conductivity of the membranes with 10% H3PO4 was in the order of 10−2 S/cm which is appreciable for an electrolyte membrane for application in fuel cell. The composite membrane was also tested for its performance in PEMFC and DMFC units of 25 cm2 area designed in our lab. The maximum power density of PEMFC with composite membranes (2 and 10% phosphoric acid) was 77.5 and 84 mW/cm2 respectively, and that of DMFC 38 and 44 mW/cm2.
  PubDate: 2011-12-01
Study on the effect of nanosilica particles on morphology, thermo-mechanical and electrical properties of liquid polysulfide modified epoxy hybrid nanocomposites
- Abstract: Abstract The modification of epoxy resin with polysulfide polymer has been carried out by keeping the ratio of polysulfide polymer and epoxy resin as constant in order to avoid phase separation. The nanocomposites have been prepared by an ex-situ technique. The effect of nanosilica loading on mechanical property, thermo—mechanical properties, morphology, and dielectric properties has been studied. It is found that the tensile properties decrease with the increase in nanosilica loading for all the nanocomposites system except for 3 wt% nanosilica loading. This has been attributed to the better dispersion of nanosilica particles in modified epoxy matrix at 3 wt% loading compared to other systems which has been observed from transmission electron microscopy (TEM) images. Dynamic mechanical analysis (DMA) study shows that the storage modulus value and tanδ peak height is decreasing with the increase in nanosilica loading in the modified epoxy matrix. There is the increase in thermal stability with the incorporation of nanosilica in base polymer system. Dielectric study reveals that there is only one relaxation peak, and the dielectric constant value decreases with the increase in frequency as well as nanosilica loading. Fourier transfer infra-red (FTIR) study has also been carried out for the composite systems.
  PubDate: 2011-12-01