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Krishna Prasad G.,PSG College of Technology | Krishna Prasad G.,Central Institute for Research on Cotton Technology | Periyasamy S.,PSG College of Technology | Chattopadhyay S.K.,Central Institute for Research on Cotton Technology | And 3 more authors.
Journal of the Textile Institute | Year: 2016

Nylon-6,6 fabric was treated with formic acid for surface roughening and was subjected to Resorcinol Formaldehyde Latex treatment for making rubber composites. Physicochemical effects of surface roughening of nylon were evidenced using scanning electron microscope (SEM), Fourier Transform Infrared spectroscope (FTIR) and differential scanning calorimeter (DSC). Further, the treatment effect on interfacial adhesion was quantified through peel strength test. The process parameters of the formic acid treatment were optimized using Box-Behnken method through geometrical surface roughness obtained through Kawabata evaluation system for micro-surface roughness of nylon to ensure good interfacial adhesion with rubber. Surface modification conditions of 11.2% formic acid concentration, 70 °C temperature and 30 min time were found to yield optimum condition at which surface roughness (SMD) was found to be of 20.1 μm. SEM analysis confirmed the presence of heterogeneous appearance like cracks, etches and micro-rough surfaces on the treated Nylon-6,6 fibre surface. FTIR analysis showed changes in –C = O stretching and –N–H stretching. No significant change was noted in the DSC curve. The peel strength between the rubber and treated fabric was improved to 150% in warp and 124% in weft directions, respectively with reference to the control fabric. © 2016 The Textile Institute

Dubey K.A.,Bhabha Atomic Research Center | Bhardwaj Y.K.,Bhabha Atomic Research Center | Chaudhari C.V.,Bhabha Atomic Research Center | Goel N.K.,Bhabha Atomic Research Center | And 3 more authors.
Polymers for Advanced Technologies | Year: 2011

Varying compositions of styrene-butadiene rubber (SBR) and ethylene-propylene diene monomer (EPDM) 50:50 blend containing multiple walled carbon nanotube (MWNT) as nanoparticulate filler (0.5-5%) were prepared and their efficacy for radiation vulcanization was analyzed by gel-content, Charlesby-Pinner parameter, and crosslinking density measurements. Radiation sensitivity of the nanocomposites increased with increase in the MWNT fraction and radiation dose in the dose range studied. The elastic modulus, tensile strength increased with the radiation dose, while elongation at break exhibited downward trend. The extent of reinforcement as assessed using Kraus equation suggested high reinforcement of blend on MWNT addition. The reinforcing mechanism of nanocomposites was studied by various micromechanics models which predicted higher modulus than the experimentally observed results, indicating agglomeration in the nanocomposites. The thermal stability of the composites increased with increase in MWNT loading has been attributed to the antioxidancy induced by nanotubes and higher crosslinking extent of the nanocomposites. © 2010 John Wiley & Sons, Ltd.

Dubey K.A.,Bhabha Atomic Research Center | Bhardwaj Y.K.,Bhabha Atomic Research Center | Rajkumar K.,Indian Rubber Manufacturers Research Association | Panicker L.,Bhabha Atomic Research Center | And 3 more authors.
Journal of Polymer Research | Year: 2012

Synergistic effect of MWNT induced reinforcement and high energy radiation induced crosslinking on the physico-mechanical and thermal characteristics of poly-chloroprene rubber (PCR)/ethylene-propylene diene rubber (EPDM)/MWNT elastomeric nanocomposites was investigated. The extent of reinforcement, as assessed using the Kraus equation suggested high reinforcement of the blend on MWNT addition; though, the thermal stability and glass transition of the PCR and EPDM components were not significantly affected by MWNTs. The elastic modulus increased with the radiation dose as well as with the increase in MWNT content. The reinforcing mechanism of the nano-composites was studied by various micro-mechanics models all of which predicted higher moduli than the experimentally observed results, indicating agglomeration in the nano-composites. Nevertheless, in all the composites synergistic effect of radiation crosslinking and MWNT induced reinforcement were seen, suggesting radiation induced cross-linking between polymer and MWNT interface. © Springer Science+Business Media B.V. 2012.

Chakraborty S.K.,Indian Rubber Manufacturers Research Association | Sabharwal S.,Bhabha Atomic Research Center | Das P.K.,Indian Rubber Manufacturers Research Association | Sarma K.S.S.,Bhabha Atomic Research Center | Manjula A.K.,Indian Rubber Manufacturers Research Association
Journal of Applied Polymer Science | Year: 2011

Effect of electron beam (EB) pretreatment on tire components has been investigated. The technique proved to be incredibly useful for reducing curing time of thick rubber products in the press and enhancing or retaining the properties required by a tire. This unique technique can be use to incorporate mixed crosslink in rubber products. Investigations were performed both on experimental compounds and industrial compounds. Experimental compound study was limited to development of theoretical data, effect of particular ingredients on EB radiation curing, and evaluating optimum dose required for obtaining optimum properties and reduction in cure time. The same sequence of study was followed on the compounds of tire components obtained from a reputed tire manufacturer. Components of tire such as inner liner and tread were irradiated with optimum doses selected in line with the study conducted on the experimental and industrial compounds. These components were then used to build the green tire. Properties of compound and tire as a whole were checked and are reported in detail in the article. Copyright © 2010 Wiley Periodicals, Inc.

Bansod N.D.,Visvesvaraya National Institute of Technology | Kapgate B.P.,Visvesvaraya National Institute of Technology | Kapgate B.P.,Indian Rubber Manufacturers Research Association | Das C.,Visvesvaraya National Institute of Technology | And 4 more authors.
Journal of Sol-Gel Science and Technology | Year: 2016

Abstract: Controlled growth of in situ silica, into natural rubber (NR)/nitrile rubber (NBR) blend (40/60 composition by weight) following solution sol–gel method, results in a coherent blend morphology with enhanced composite properties. Similar composites, i.e., in situ silica-filled NR/NBR blend (40/60 by weight), showed better mechanical properties than any other composition that were prepared by soaking sol–gel method in earlier study. However, silica content in the rubber blend was limited to 20 phr (parts per hundred parts of rubber) and could not be increased under experimental condition following soaking sol–gel method. In the present work, silica content is increased (up to 30 phr) beyond that limit for the same blend composition. Accordingly, mechanical properties of the NR/NBR composites are improved. Use of a silane coupling agent, viz., bis-(3-triethoxysilylpropyl)-tetra sulfide, in the reactive sol–gel system during in situ silica generation brings in remarkable effect in silica distribution, rubber–filler interaction and mechanical properties of the composites. TEM micrographs of the selected composites reveal that silica is mostly grown at the interfacial region, when silane is used in particular. This results in further enhancement in mechanical properties and compatibility of the blend at the same silica content as evident from stress–strain and dynamic mechanical analysis studies. The reinforcement of effect in situ silica is assessed by Guth–Gold equation and modified form of Guth equation (with shape factor f = 2.53). The results are supported by the detailed studies on rheological, morphological, mechanical and viscoelastic properties of the composites. Graphical Abstract: [Figure not available: see fulltext.] © 2016 Springer Science+Business Media New York

Rajkumar K.,Indian Rubber Manufacturers Research Association | Rajkumar K.,Bharathiar University | Kumari N.,Indian Rubber Manufacturers Research Association | Ranjith P.,Indian Rubber Manufacturers Research Association | And 4 more authors.
International Journal of ChemTech Research | Year: 2011

The high temperature resistant Polymer-nanographite composite was prepared using Nanographite as reinforcing fillers in Acrylonitrile Butadiene Rubber (NBR) and investigated. The effect of increasing nanographite loadings on mechanical properties like tensile strength, modulus and Elongation at break was studied. Mechanical tests demonstrate that the NBR/graphite nanocomposites possess greatly increased elastic modulus and tensile strength, and desirably strong interfaces. The NBR nanocomposites showed higher thermal stability in comparison unfilled rubber vulcanizate. Physico-mechanical properties of the polymer nanocomposites after air ageing studies at 200°C showed improved thermal resistance and increases with loading of nanographite. The dispersion of the nanographite filler in the Nitrile Rubber was achieved using liquid NBR polymer matrix and was investigated by SAXD, SEM and Mechanical properties. SAXD study indicated that the composites did not change the inter-gallery distance (d-spacing) of the graphite platelets and as the loading of nano filler increases the dispersion of nanoparticles improved due to filling effect.

Kotal M.,Indian Institute of Technology Kharagpur | Srivastava S.K.,Indian Institute of Technology Kharagpur | Bhowmick A.K.,Indian Institute of Technology Kharagpur | Chakraborty S.K.,Indian Rubber Manufacturers Research Association
Polymer International | Year: 2011

In the past few years, layered double hydroxides (LDHs) with monolayer structure have been much studied for the development of polymer nanocomposites. LDHs with intercalated stearate anions form a bilayer structure with increased interlayer spacing and are expected to be better nanofillers in polymers. In the work reported, thermoplastic polyurethane (PU)/stearate-intercalated LDH nanocomposites were prepared by solution intercalation and characterized. X-ray diffraction and transmission electron microscopy confirmed the exfoliation at lower filler loading followed by intercalation at higher filler loading in PU matrix. As regards mechanical properties, these nanocomposites showed maximum improvements in tensile strength (45%) and elongation at break (53%) at 1 and 3 wt% loadings. Maximum improvements in storage and loss moduli (20%) with a shift of glass transition temperature (15 °C) and an increase in thermal stability (32 °C) at 50% weight loss were observed at 8 wt% loading in PU. Differential scanning calorimetry showed a shift of melting temperature of the soft segment in the nanocomposites compared to neat PU, possibly due to the nucleating effect of stearate-intercalated LDH on the crystal structure of PU. All these findings are promising for the development of mechanically improved, thermally stable novel PU nanocomposites. Copyright © 2011 Society of Chemical Industry Polyurethane (PU)/stearate-intercalated layered double hydroxide (LDH) nanocomposites have been prepared by solution blending and characterized to investigate the influence of stearate intercalation in LDH on the properties of the nanocomposites. © 2011 Society of Chemical Industry.

Rajkumar K.,Indian Rubber Manufacturers Research Association | Ranjan P.,Indian Rubber Manufacturers Research Association | Thavamani P.,Indian Rubber Manufacturers Research Association | Jeyanthi P.,Bharathiar University | Pazhanisamy P.,Bharathiar University
Rasayan Journal of Chemistry | Year: 2013

Polymer-nanosilica composite was prepared using Silica nano particles as reinforcing fillers in Acrylonitrile Butadiene Rubber (NBR). The rheological behavior of the polymer nano composite was studied using Rubber Process Analyzer [RPA-2000, USA]. The dispersion of the silica nano particles based filler in the Nitrile Rubber was achieved using liquid NBR polymer matrix and was investigated by FTIR, SEM-EDS. The effect of increasing nano-silica loadings on mechanical properties of NBR nanocomposites was also studied. Mechanical tests demonstrate that the NBR/nano-silica based polymer nano composites possess greatly increased the elastic modulus and tensile strength, and desirably strong interfaces. The thermal resistance properties of NBR Nano-composites were studied through air ageing studies at 100°C and characterized through TGA studies. © 2013 RASAYAN. All rights reserved.

Patil A.G.,National Institute of Technology Karnataka | Poornachandra S.,National Institute of Technology Karnataka | Gumageri R.,National Institute of Technology Karnataka | Rajkumar K.,Indian Rubber Manufacturers Research Association | Anandhan S.,National Institute of Technology Karnataka
Journal of Material Cycles and Waste Management | Year: 2016

This paper outlines the preparation and characterization of chitosan (CS) composites reinforced with mechano-chemically activated fly ash (MCA-FA). A series of composite films was prepared by solution casting method with varying filler content. Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD) analyses showed good compatibility between the CS matrix and MCA-FA. The surface roughness and irregularity in shape of MCA-FA resulted in its efficient mechanical interlocking with the polymer matrix. This, in turn enhanced the mechanical properties of these composites. All the composite films exhibited a higher tensile strength and a lower percentage of elongation-at-break compared with the pure CS film. The highest tensile strength was observed for the composite films with 1 wt% of filler loading and the reduction in the tensile properties at higher filler loading was due to agglomeration of filler and polymer–filler interface debonding. The tensile strength data were analyzed using Nielsen and Pukanzsky models to understand the interface formation and polymer–filler interactions. Thermal properties showed a marginal improvement due to the incorporation of MCA-FA. Overall, this study indicates that MCA-FA could be used as value added filler in polymer matrix composites. © 2016 Springer Japan

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