02324nas a2200265   4500008004100000022001400041245013400055210006900189260007300258300001200331490000800343520134700351653001901698653002301717653001401740653002401754653002101778653002201799653002601821100002201847700002501869700002201894700001601916856012601932       2007                        eng d  a0378-775300aHigh-temperature, polymer-graphite hybrid composites for bipolar plates: effect of processing conditions on electrical properties0 aHightemperature polymergraphite hybrid composites for bipolar pl  aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcJAN  a702-7070 v1633 a<p>High-temperature thermoplastic-graphite composites are prepared using polyphenylene sulfide (PPS) and polyether sulfone (PES) containing natural graphite powder. All samples are prepared by high pressure compaction and heating to high temperatures. The effect of a third additional conducting component on the electrical resistance of these composites is studied. A low resistance of the order of 0.1 Omega can be obtained even for a graphite concentration of 50% by addition of the third component. The effect of a mixing/blending technique on the anisotropy of conductivity is investigated. Solution blending of PES with graphite leads to lower anisotropy values than powder mixing and compression moulding. The samples when exposed continuously to a working temperature of 100 degrees C give a small but significant reduction in electrical resistance. X-ray diffraction studies on composites prepared by different techniques indicate that there is restructuring and crystallite re-orientation of the graphite phase in the samples. A large reduction in the crystallite size is observed for samples prepared by solution blending while re-orientation occurs after heat treatment. The changes in electrical properties can be correlated with these structural transformations in the composites. (c) 2006 Elsevier B.V. All rights reserved.</p>10abipolar plates10aconducting polymer10afuel cell10agraphite composites10ahybrid materials10apolyether sulfone10apolypherylene sulfide1 aRadhakrishnan, S.1 aRamanujam, B., T. S.1 aAdhikari, Arindam1 aSivaram, S.  uhttps://library.ncl.res.in/content/high-temperature-polymer-graphite-hybrid-composites-bipolar-plates-effect-processing-001889nas a2200229   4500008004100000022001400041245010200055210006900157260010000226300001400326490000700340520096800347653004401315653002601359653001301385653001301398653005301411100002501464700002601489700002201515856012201537       2010                        eng d  a0266-353800aPolyethersulfone-expanded graphite nanocomposites: charge transport and impedance characteristics0 aPolyethersulfoneexpanded graphite nanocomposites charge transpor  aTHE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLANDbELSEVIER SCI LTDcNOV0  a2111-21160 v703 a<p>Polyethersulfone (PES)-expanded graphite nanocomposites have been prepared by solution blending route after sonicating expanded graphite in dichloromethane. It has been observed that ultrasonication results in nanosheets formation leading to a low percolation threshold of 3 wt.%. At 5 wt.% filler loading the conductivity is of the order of 10(-2) S/cm. Hopping type of charge transport occurs at 3.2 wt.% expanded graphite in PES below which capacitive effects couple. The effective dielectric constant at low frequency increases with filler concentration. Impedance measurement has been carried out to evaluate interfacial capacitance which, for 3.2 wt.% expanded graphite addition in PES, increases to 110 pF from 32 pF for 1 wt.% expanded graphite in the polymer. DSC analysis shows an increment of 12 C in the T(g) of PES with 3 wt.% expanded graphite suggesting interaction between the polymer and filler. (C) 2010 Elsevier Ltd. All rights reserved.</p>10aDifferential scanning calorimetry (DSC)10aElectrical properties10aModeling10aPolymers10aScanning/transmission electron microscopy (STEM)1 aRamanujam, B., T. S.1 aMahale, Rajashree, Y.1 aRadhakrishnan, S.  uhttps://library.ncl.res.in/content/polyethersulfone-expanded-graphite-nanocomposites-charge-transport-and-impedance-001700nas a2200157   4500008004100000245011100041210006900152260000800221300001200229490000700241520109500248100002501343700002201368700002701390856012501417       2017                        eng d00aAnalysis of electrical and thermal conductivities of polyethersulfone-graphite based hybrid nanocomposites0 aAnalysis of electrical and thermal conductivities of polyethersu  cAPR  a311-3160 v253 aPolyethersulfone (PES)-7 wt% graphite- x wt% filler (carbon black (CB), carbon nanofiber (CNF), expanded graphite (ExGr)) hybrid composites are synthesized by solution blending route. The electrical percolation threshold in hybrid composites varies exponentially with the aspect ratio of the second conducting filler. The aspect ratio of the second conducting filler has been found to vary in the order CB < CNF < ExGr. The percolation threshold is identified at 0.05 wt%, 0.4 wt%, 1.3 wt% for ExGr, CNF and CB added PES-7 wt% graphite composites. Through plane thermal conductivity of PES-x wt% graphite-y wt% CB (x=10, 20, 30, 40, 50, 60, y=0, 3, 7) hybrid composites has been found to increase with the addition of CB. Thermal conductivity has been increased to 0.42 W/m-K when 7 wt% CB is added to PES-60 wt% graphite from 0.2 W/m-K. Reduction of interparticular distance with the increased loading of CB facilitates better thermal transport. Aspect ratios of second conducting fillers have been found out from transmission electron microscopy and scanning electron microscopy analysis.1 aRamanujam, B., T. S.1 aRadhakrishnan, S.1 aDeshpande, Shripad, D.  uhttps://library.ncl.res.in/content/analysis-electrical-and-thermal-conductivities-polyethersulfone-graphite-based-hybrid01530nas a2200157   4500008004100000245011100041210006900152260000800221300001400229490000700243520092100250100002501171700002201196700002201218856013201240       2017                        eng d00aPolyphenylene sulfide- expanded graphite nanocomposites: processing route dependent electrical percolation0 aPolyphenylene sulfide expanded graphite nanocomposites processin  cDEC  a1603-16140 v303 aPolyphenylene sulfide (PPS)-expanded graphite (ExGr) conducting nanocomposites have been prepared by powder mixing and in situ polymerization routes after sonicating ExGr particles in acetone. Synthesized PPS has been used to make powder mixed composites. The powder mixed composites exhibit a percolation threshold of 3 wt% due to the formation of graphite nanosheets. When PPS-ExGr composites are prepared by in situ polymerization route, very low electrical percolation threshold less than 0.5 wt% ExGr is obtained. The low percolation threshold obtained is attributed to better dispersion of ExGr nanosheets in the polymer matrix when compared to powder mixed composites. The synthesized PPS has been characterized by X-ray diffraction, differential scanning calorimetry, and infrared spectroscopy. The formation of graphite nanosheets has been confirmed by transmission and scanning electron microcopy analysis.1 aRamanujam, B., T. S.1 aRadhakrishnan, S.1 aDeshpande, S., D.  uhttps://library.ncl.res.in/content/polyphenylene-sulfide-expanded-graphite-nanocomposites-processing-route-dependent-electrical02354nas a2200265   4500008004100000022001400041245013200055210006900187260000800256300001200264490000700276520141300283653002101696653003401717653002601751653002401777653002201801653001601823653001301839653003701852100002501889700002201914700002201936856013001958       2017                        eng d  a0892-705700aPolypropylene-based conducting nanocomposites: effect of aspect ratio of second conducting filler on the electrical percolation0 aPolypropylenebased conducting nanocomposites effect of aspect ra  cJUN  a840-8540 v303 a<p>Powder-mixed polypropylene (PP)-graphite binary composites exhibit an electrical percolation threshold at 10 wt% graphite signifying insulator-semiconductor transition. Three conducting fillers such as carbon black (CB), sonicated expanded graphite (s-ExGr), and carbon nanofiber (CNF) are mixed with PP-7 wt% graphite binary composites. The electrical percolation threshold has been found to have inverse relation to the aspect ratio of second conducting fillers in hybrid composites. The aspect ratio of second conducting fillers varies in the order CB &lt; ExGr &lt; CNF. The electrical percolation threshold is found to vary for the hybrid composites as 2.2 wt% for CB addition, 0.75 wt% for ExGr addition, and 0.2 wt% for CNF addition in the PP-7 wt% graphite binary composites. When the aspect ratio of second conducting fillers increases, they reduce the barrier for the charge transport. The second conducting fillers occupy the interspace of graphite and alternating current studies show that the effective dielectric constant increases with the concentration of second conducting filler in the hybrid composites. The composites are characterized by transmission electron microscopy and scanning electron microscopy. Melt-crystallized PP-7 wt% graphite-CNF composites exhibit higher percolation threshold due to decrease in the polymer viscosity which increases the interparticulate distance.</p>10acarbon nanofiber10aConducting polymer composites10aElectrical properties10agraphite nanosheets10ahybrid composites10apercolation10ascanning10atransmission electron microscopy1 aRamanujam, B., T. S.1 aRadhakrishnan, S.1 aDeshpande, S., D.  uhttps://library.ncl.res.in/content/polypropylene-based-conducting-nanocomposites-effect-aspect-ratio-second-conducting-filler