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Marco-a. De Paoli - One of the best experts on this subject based on the ideXlab platform.

  • Microwave Absorbing Coatings Based on a Blend of Nitrile Rubber, EPDM Rubber and Polyaniline
    Polymer Bulletin, 2005
    Co-Authors: Roselena Faez, Aline D. Reis, Mauro A. Soto-oviedo, Mirabel Cerqueira Rezende, Marco-a. De Paoli
    Abstract:

    The mechanical and microwave radiation absorbing properties of conductive ternary blends based on Nitrile Rubber, EPDM Rubber and polyaniline, doped with dodecylbenzene sulfonic acid, have been investigated with special interest in the concentrations of Nitrile Rubber and conductive polymer in the blend. The ternary blends were prepared by melt blending using an internal mixer. Mechanical properties and soluble fraction analyses show that crosslinking occurs during blending, and that the crosslinking degree depends on the concentrations of doped polyaniline and Nitrile Rubber in the blend. The crosslinking reaction involves the doping acid (dodecylbenzene sulfonic acid) of polyaniline and the -C≡N group in the Nitrile Rubber. The ternary blends can be used for microwave absorption in the frequency range of 8–12 GHz. This property depends on the concentration of the conductive polymer and film thickness.

  • An electroactive elastomer: polyaniline/Nitrile Rubber
    Polymer, 1992
    Co-Authors: Eliana L. Tassi, Marco-a. De Paoli
    Abstract:

    An electroactive elastomeric material was prepared by the electrochemical graft copolymerization of aniline with Nitrile Rubber. The synthesis has been carried out potentiostatically, potentiodynamically or galvanostatically in a non-aqueous medium using a Nitrile-Rubber-coated working electrode. Infra-red spectra of the products resemble a superposition of Nitrile Rubber and polyaniline spectra. However, thermogravimetry, differential scanning calorimetry and solubility experiments indicate that the polyaniline chains grow as grafted branches of the Nitrile Rubber chains. Scanning electron microscopy indicates no phase segregation in accordance with this assumption. Cyclic voltammetry experiments indicate that the new material has the same electroactivity as pure polyaniline. © 1992.

Anil K. Bhowmick - One of the best experts on this subject based on the ideXlab platform.

  • Influence of radiation temperature on the crosslinking of Nitrile Rubber by electron beam irradiation
    Radiation Physics and Chemistry, 2008
    Co-Authors: V. Vijayabaskar, Anil K. Bhowmick, Michael Stephan, S. Kalaivani, Sebastian Volke, Gert Heinrich, Helmut Dorschner, Udo Wagenknecht
    Abstract:

    Abstract Nitrile Rubber with 18% acryloNitrile content in presence and absence of polyfunctional monomers like trimethylolpropane triacrylate (TMPTA), tripropyleneglycol diacrylate (TPGDA), tetramethylolmethane tetraacrylate (TMMT) and m-phenylene bismaleimide was subjected to electron beam irradiations at different temperatures. The structural changes with different doses of radiations were investigated with the help of FTIR spectroscopy (in the ATR mode), dynamic mechanical thermal analysis and sol–gel analysis. There was a decrease in the concentration of olefinic groups for this elastomer on radiation at high temperature as compared to the room temperature. The increase in crosslinking at elevated temperature was also revealed by the increase in % gel content and dynamic storage moduli with radiation dose. The lifetime of spurs, an important criterion for overlapping of spurs, was determined for both grafted and ungrafted Nitrile Rubber using a mathematical model. The ratio of scissioning to crosslinking for Nitrile Rubber was determined using Charlesby–Pinner equation. The mechanical properties were studied and the tensile strength was found to increase with grafting of polyfunctional monomers on irradiation at high temperature.

  • Crosslinking of Nitrile Rubber by electron beam irradiation at elevated temperatures
    Kgk-kautschuk Gummi Kunststoffe, 2007
    Co-Authors: Michael Stephan, V. Vijayabaskar, S. Kalaivani, Sebastian Volke, Gert Heinrich, H. Dorsch Ner, Udo Wagenknecht, Anil K. Bhowmick
    Abstract:

    The influence of different temperatures on electron beam irradiation of Nitrile Rubber with 18% acryloNitrile content in presence and absence of polyfunctional monomers like trimethylolpropane triacrylate (TMPTA), tripropyleneglycol diacrylate (TPGDA), trimethylolmethane tetraacrylate (TMMT) and m-phenylene bismaleimide were studied. The structural changes with different doses of radiations were investigated with the help of FTIR spectroscopy (in the ATR mode), dynamic mechanical thermal analysis and sol-gel analysis. The ratio of scissioning to crosslinking for Nitrile Rubber has been determined using the Charlesby-Pinner equation. The mechanical properties have been studied and the tensile strength is found to increase with grafting of polyfunctional monomers on irradiation at high temperature.

  • Electron beam modification and crosslinking: Influence of Nitrile and carboxyl contents and level of unsaturation on structure and properties of Nitrile Rubber
    Radiation Physics and Chemistry, 2006
    Co-Authors: V. Vijayabaskar, V.k. Tikku, Anil K. Bhowmick
    Abstract:

    Abstract The structural changes of Nitrile Rubber with varying Nitrile contents, hydrogenated Nitrile Rubber and carboxylated Nitrile Rubber in the presence and absence of a polyfunctional monomer, namely trimethylolpropane triacrylate, at different doses of electron beam irradiation, were investigated with the help of FTIR spectroscopy (in the attenuated total reflectance mode), dynamic mechanical thermal analysis and sol–gel analysis. Solid-state NMR with gated high power decoupling technique was used to understand the mechanism of crosslinking of the irradiated samples. The allylic radicals generated in the butadiene chains react to form intermolecular crosslinkages. There was a significant decrease in the concentration of olefinic groups for the Nitrile Rubber on irradiation. This was also affirmed by the increase in the carbon resonances due to C–C linkages from the NMR technique, indicating more crosslinkages. The spectroscopic crosslink densities were determined and the results were compared with the swelling measurements. The variation in the crosslink clustering for Rubbers with different acryloNitrile contents was explained using the NMR technique. The increase in crosslinking was also revealed by the increase in the percent gel content and dynamic storage moduli with radiation doses. The lifetime of spurs formed and the critical dose, an important criterion for overlapping of spurs, were determined for both the grafted and the ungrafted Nitrile Rubbers of different grades and compared using a mathematical model. The ratio of scissioning to crosslinking for Nitrile Rubber was determined using Charlesby–Pinner equation. The mechanical properties had also been studied for both the modified and the unmodified systems.

  • Electron‐beam modification of Nitrile Rubber in the presence of polyfunctional monomers
    Journal of Applied Polymer Science, 2005
    Co-Authors: V. Vijayabaskar, Anil K. Bhowmick
    Abstract:

    The structural changes of Nitrile Rubber in both the presence and the absence of polyfunctional monomers, such as trimethylolpropane triacrylate (TMPTA), tripropyleneglycol diacrylate (TPGDA), and trimethylolmethane tetraacrylate (TMMT), at different doses of electron beam irradiations, were investigated with the help of FTIR spectroscopy (in the ATR mode), solid-state NMR, dynamic mechanical thermal analysis, and sol–gel analysis. There was a significant decrease in the concentration of olefinic groups for modified system with 3% TMPTA compared to that of the unmodified Nitrile Rubber on irradiation. This was also confirmed by the increase in the carbon resonances attributed to CC linkages from solid-state NMR for the modified system, indicating more crosslinkages. The increase in crosslinking was also revealed by the increase in % gel content and dynamic storage moduli with radiation dose. The lifetime of spurs formed and the critical dose, an important criterion for overlapping of spurs, were determined for both grafted and ungrafted Nitrile Rubber using a mathematical model. The ratio of scissioning to crosslinking for Nitrile Rubber was determined using the Charlesby–Pinner equation. Mechanical properties were studied for the modified and the unmodified systems and the tensile strength was found to increase with grafting of polyfunctional monomers. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 95: 435–447, 2005

  • Thermoplastic Elastomeric Blend of Nitrile Rubber and Poly(styrene-co-acryloNitrile). II. Replacement of Nitrile Rubber by Its Vulcanizate Powder
    Journal of Applied Polymer Science, 2003
    Co-Authors: S. Anandhan, Anil K. Bhowmick, S. Bandyopadhyay
    Abstract:

    A model waste Nitrile Rubber powder (w- NBR) was prepared by ambient grinding of aged NBR vul- canizate based on an oil seal formulation. The w-NBR was characterized by scanning electron microscopic and optical microscopic techniques. Virgin Nitrile Rubber in a thermo- plastic elastomeric 70:30 Nitrile Rubber/poly(styrene-co- acryloNitrile) (SAN) blend was replaced by w-NBR, and the mechanical properties and swelling index were determined. The virgin NBR in the blend was replaced by the Rubber present in w-NBR (r-w-NBR) and the optimum mechanical properties were achieved at 45% replacement where the blend was still reprocessable. Transmission electron micro- scopic and atomic force microscopic studies reveal that w- NBR particles coated with NBR are dispersed in a continu- ous SAN matrix. It was observed that migration of unre- acted curatives from w-NBR to virgin NBR is not significant and incorporation of curatives is necessary for attainment of optimum level of mechanical properties. © 2003 Wiley Period-

Sabu Thomas - One of the best experts on this subject based on the ideXlab platform.

  • thermal and crystallisation behaviour of isotactic polypropylene Nitrile Rubber blends
    Polymer, 2000
    Co-Authors: Snooppy George, K. T. Varughese, Sabu Thomas
    Abstract:

    The thermal stability of isotactic polypropylene (PP)/Nitrile Rubber (NBR) was studied using thermogravimetry. The effects of blend ratio, compatibilisation and dynamic vulcanisation on thermal stability were investigated. The addition of Nitrile Rubber to polypropylene was found to improve the thermal stability of polypropylene. The compatibilisation of the blends using phenolic modified polypropylene and maleic anhydride modified propylene has increased the degradation temperature and decreased the weight loss. The dynamic vulcanisation of the blends also improved the thermal stability. The melting behaviour was investigated by differential scanning calorimetry for the binary blends. The crystallinity of the blends decreased with increase in NBR content. The crystalline structure of the blends was investigated using wide angle X-ray scattering. The polypropylene and the blends exist in the α-monoclinic form as shown by the presence of four maximas. The compatibilisation of the blends did not affect the α-monoclinic crystalline structure. The addition of NBR to polypropylene increased the interplanar distance.

  • Thermal and crystallisation behaviour of isotactic polypropylene/Nitrile Rubber blends
    Polymer, 2000
    Co-Authors: Snooppy George, K. T. Varughese, Sabu Thomas
    Abstract:

    The thermal stability of isotactic polypropylene (PP)/Nitrile Rubber (NBR) was studied using thermogravimetry. The effects of blend ratio, compatibilisation and dynamic vulcanisation on thermal stability were investigated. The addition of Nitrile Rubber to polypropylene was found to improve the thermal stability of polypropylene. The compatibilisation of the blends using phenolic modified polypropylene and maleic anhydride modified propylene has increased the degradation temperature and decreased the weight loss. The dynamic vulcanisation of the blends also improved the thermal stability. The melting behaviour was investigated by differential scanning calorimetry for the binary blends. The crystallinity of the blends decreased with increase in NBR content. The crystalline structure of the blends was investigated using wide angle X-ray scattering. The polypropylene and the blends exist in the α-monoclinic form as shown by the presence of four maximas. The compatibilisation of the blends did not affect the α-monoclinic crystalline structure. The addition of NBR to polypropylene increased the interplanar distance.

  • Liquid Natural Rubber as a Viscosity Modifier in Nitrile Rubber Processing
    Polymer International, 1997
    Co-Authors: N. Radhakrishnan Nair, Sabu Thomas, N. M. Mathew
    Abstract:

    The use of thermally depolymerised liquid natural Rubber as a plasticiser in Nitrile Rubber has been investigated with special reference to the rheological aspects. A comparative evaluation has been made with dibutylphthalate, the ester-type plasticiser commonly used with Nitrile Rubber. The study revealed that the use of liquid natural Rubber as a plasticiser and viscosity modifier improved the processability of the compounds and also enhanced many of the vulcanisate properties. © of SCI.

Anatoli Serghei - One of the best experts on this subject based on the ideXlab platform.

  • Study on Weather Aging of Nitrile Rubber Composites Containing Imidazolium Ionic Liquids
    Macromolecular Symposia, 2014
    Co-Authors: Anna Marzec, Anna Laskowska, Gisèle Boiteux, Marian Zaborski, Olivier Gain, Anatoli Serghei
    Abstract:

    Weather aging of Nitrile Rubber composites containing hydrophilic 1-ethyl-3-methylimidazolium thiocyanate (EMIM SCN) and hydrophobic 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide (EMIM TFSI), and 1-allyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide (AMIM TFSI) ionic liquids was investigated. The mechanical properties at small (dynamic mechanical analysis) and high deformation (tensile test), the hardness and the electrical properties were measured before and after the aging process. It was found that the presence of hydrophobic ionic liquids in the Nitrile Rubber enhanced the retention of their mechanical properties (tensile strength, stiffness) and slightly reduced surface defects (as determined by scanning electron microscopy), thereby retarding the aging of Rubber composites. However, the presence of hydrophilic EMIM SCN in the composite accelerated the degradation of the studied materials because of its high crosslinking activity during the aging process. The electrical studies showed also lower stability of hydrophilic ionic liquid (EMIM SCN) in the studied Nitrile matrix (leaking effects) compared to the hydrophobic one (EMIM TFSI, AMIM TFSI).

  • Properties of Carboxylated Nitrile Rubber/Hydrotalcite Composites Containing Imidazolium Ionic Liquids
    Macromolecular Symposia, 2014
    Co-Authors: Anna Marzec, Anna Laskowska, Gisèle Boiteux, Marian Zaborski, Olivier Gain, Anatoli Serghei
    Abstract:

    In the present study, two types imidazolium salts containing the common cation 1-butyl-3-methylimidazolium-hydrophilic tetrachloroaluminate (BMIM AlCl4) and hydrophobic bis(trifluoromethylsulfonyl) imide (BMIM TFSI) are analyzed for effects on the ionic conductivity and the state of cure of carboxylated Nitrile Rubber/hydrotalcite composites (XNBR/HT). Imidazolium salt containing tetrachloroaluminate ions effectively participates in the crosslinking process of carboxylated Nitrile Rubber and contributes to an increase in the crosslink density of the composites. Hydrophobic 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide was found to be compatible with carboxylated Nitrile Rubber. In the presence of 15 parts per hundred Rubber (phr) of BMIM TFSI, the ionic conductivity of the composites increases from 10(-10) to 10(-7) S center dot cm(-1), and the glass transition temperature (T-g) of the XNBR shifts towards lower temperatures from -23 degrees C to -33 degrees C.

  • Effect of imidazolium ionic liquid type of Nitrile Rubber composites
    Polymer International, 2013
    Co-Authors: Anna Laskowska, Anna Marzec, Gisèle Boiteux, Marian Zaborski, Olivier Gain, Anatoli Serghei
    Abstract:

    We investigated the influence of hydrophilic and hydrophobic imidazolium ionic liquids on the curing kinetic, mechanical, morphological and ionic conductivity properties of Nitrile Rubber composites. Two room temperature ionic liquids with a common cation--1-ethyl-3-methylimidazolium thiocyanate (EMIM SCN; hydrophilic) and 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (EMIM TFSI; hydrophobic)--were used. Magnesium-aluminium layered double hydroxide (MgAl-LDH; also known as hydrotalcite) was added to carboxylated acryloNitrile-butadiene Rubber (XNBR) whereas fumed silica Aerosil 380 was used in acryloNitrile-butadiene Rubber (NBR) as reinforcing fillers. NBR compounds were vulcanized with a conventional sulfur-based crosslinking system whereas XNBR compounds were cured with MgAl-LDH. The optimum cure time reduction and tensile properties improvement were obtained when both ionic liquids were added at 5 parts per hundred Rubber (phr). The results revealed that EMIM SCN and EMIM TFSI induced an increase in the AC conductivity of Nitrile Rubber composites from 10−10 to 10−8 and to 10−7 S cm−1, respectively (at 15 phr ionic liquid concentration). The presence of ionic liquids in NBR slightly affected the glass transition temperature (Tg) whereas the presence of EMIM TFSI in XNBR contributed to a shift in Tg towards lower temperatures from −23 to −31 °C, at 15 phr loading, which can be attributed to the plasticizing behaviour of EMIM TFSI in the XNBR/MgAl-LDH system. Dynamic mechanical analysis was also carried out and the related parameters, such as the mechanical loss factor and storage modulus, were determined.

Cristina Russi Guimarães Furtado - One of the best experts on this subject based on the ideXlab platform.

  • Nitrile Rubber and carboxylated Nitrile Rubber resistance to soybean biodiesel
    2018
    Co-Authors: Felipe Nunes Linhares, Cléverson Fernandes Senra Gabriel, Ana Maria Furtado De Sousa, Marcia Christina Amorim Moreira Leite, Cristina Russi Guimarães Furtado
    Abstract:

    Abstract Biodiesel has been considered a suitable substitute for petroleum diesel, but their chemical composition differs greatly. For this reason, biodiesel interacts differently than petroleum diesel with various materials, including Rubbers. Therefore, the resistance of some elastomers should be thoroughly evaluated, specifically those which are commonly used in automotive industry. Nitrile Rubber (NBR) is widely used to produce vehicular parts that are constantly in contact with fuels. This paper aimed to assess the resistance of carboxylated Nitrile Rubber (XNBR) with 28% of acryloNitrile content to soybean biodiesel in comparison with non-carboxylated Nitrile Rubber samples, with high and medium acryloNitrile content (33 and 45%). NBR with medium acryloNitrile content showed little resistance to biodiesel. However, carboxylated Nitrile Rubber even with low acryloNitrile content had similar performance to NBR with high acryloNitrile content.

  • Effect of different sulphur-based crosslink networks on the Nitrile Rubber resistance to biodiesel
    Fuel, 2017
    Co-Authors: Felipe Nunes Linhares, Marcia Christina Amorim Moreira Leite, Michaela Kersch, Ute Niebergall, Volker Atlstädt, Cristina Russi Guimarães Furtado
    Abstract:

    Abstract Biodiesel possesses some comparable physical properties to petroleum diesel in addition to its improved environmental benefits. Nonetheless, both fuels differ greatly with respect to their chemical compositions. Therefore, the compatibility of the materials, which are commonly employed in contact with diesel, must also be assured for biodiesel. This paper assessed the influence of sulphur-based curing systems on the resistance of Nitrile Rubber to soybean biodiesel. Formulations were prepared using high-acryloNitrile-content Nitrile Rubber by employing a two-level experimental design. The amounts of two different accelerators and sulphur were varied to achieve different types of vulcanisation systems. Thermal analyses, mechanical tests and microscopy analyses were conducted to evaluate the behaviour of the material after contact with biodiesel. The results showed that the choice of the accelerator played an important role on the resistance of the Rubber to the biofuel, and crosslink density was not a key factor with respect to the resistance.