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Conductive Carbon Black (conductive + carbon_black)
Selected AbstractsSynergistic effects of carbon fillers on shielding effectiveness in conductive nylon 6,6- and polycarbonate-based resinsADVANCES IN POLYMER TECHNOLOGY, Issue 2 2003Quinton J. Krueger Abstract Electrically conductive resins can be made by adding electrically conductive fillers to typically insulating polymers. Resins with an electrical resistivity of approximately 100 , cm or less can be used for electromagnetic and radio frequency interference shielding applications. This research focused on performing compounding runs followed by injection molding and shielding effectiveness (SE) testing of carbon filled nylon 6,6- and polycarbonate-based resins. The three carbon fillers investigated included an electrically conductive carbon black, synthetic graphite particles, and a milled pitch-based carbon fiber. For each polymer, conductive resins were produced and tested that contained varying amounts of these single carbon fillers. In addition, combinations of fillers were investigated by conducting a full 23 factorial design and a complete replicate in each polymer. The objective of this study was to determine the effects and interactions of each filler on the SE properties of the conductive resins. Carbon black caused the largest increase in SE. Also, each single filler and each two filler interaction caused a statistically significant increase in SE. © 2003 Wiley Periodicals, Inc. Adv Polym Techn 22: 96,111, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/adv.10040 [source] Dielectric studies of conductive carbon black reinforced microcellular ethylene,propylene,diene monomer vulcanizatesJOURNAL OF APPLIED POLYMER SCIENCE, Issue 1 2007S. P. Mahapatra Abstract The alternating-current and electrical conductivity of conductive, carbon black reinforced, microcellular ethylene,propylene,diene monomer vulcanizates was measured in the frequency range of 100 Hz to 1 MHz. The effects of variations in the filler and blowing-agent loadings on the dielectric constant and percolation behavior were studied. The phenomenon of percolation was examined on the basis of measured changes in the electrical conductivity and morphology of composites with different concentrations of the filler. Scanning electron microphotographs showed the agglomeration of the filler above these concentrations and the formation of a continuous network structure. The experimental results were not in agreement with the predictions of the statistical percolation theory; this deviation was explained in light of the formation of an interphase or mesostructure in the composites. The variation of the dielectric constant with the filler and blowing-agent loadings was explained on the basis of polarization of the filler in the polymer matrix. Additionally, the use of dielectric mixture laws in describing the dielectric constants of both solid and microcellular composites was investigated. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007 [source] Tensile properties of carbon filled liquid crystal polymer composites,POLYMER COMPOSITES, Issue 1 2008Jason M. Keith Electrically and thermally conductive resins can be produced by adding carbon fillers. Mechanical properties such as tensile modulus, ultimate tensile strength, and strain at ultimate tensile strength are vital to the composite performance in fuel cell bipolar plate applications. This research focused on performing compounding runs followed by injection molding and tensile testing of carbon filled Vectra A950RX liquid crystal polymer composites. The four carbon fillers investigated included an electrically conductive carbon black, thermocarb synthetic graphite particles, and two carbon fibers (Fortafil 243 and Panex 30). For each different filler type, resins were produced and tested that contained varying amounts of these single carbon fillers. The carbon fiber samples exhibited superior tensile properties, with a large increase in tensile modulus over the base polymer, and very low drop in the ultimate tensile strength as the filler volume fraction was increased. The strain at the ultimate tensile strength was least affected by the addition of the Panex carbon fiber but was significantly affected by the Fortafil carbon fiber. In general, composites containing synthetic graphite did not perform as well as carbon fiber composites. Carbon black composites exhibited poor tensile properties. POLYM. COMPOS., 29:15,21, 2008. © 2007 Society of Plastics Engineers [source] Relaxation behavior of conductive carbon black reinforced EPDM microcellular vulcanizatesPOLYMER ENGINEERING & SCIENCE, Issue 7 2007S.P. Mahapatra Dynamic mechanical analysis and dielectric relaxation spectra of conductive carbon black reinforced microcellular EPDM vulcanizates were used to study the relaxation behavior as a function of temperature (,90 to +100°C) and frequency (0.01,105 Hz). The effect of filler and blowing agent loadings on dynamic mechanical and dielectric relaxation characteristics has been investigated. The effect of filler and blowing agent loadings on glass transition temperature was marginal for all the composites (Tg value was in the range of ,39 to ,35°C), which has been explained on the basis of relaxation dynamics of polymer chains in the vicinity of fillers. Strain-dependent dynamical parameters were evaluated at dynamic strain amplitudes of 0.07,5%. The nonlinearity in storage modulus has been explained based on the concept of filler,polymer interaction and interaggregate attraction (filler networking) of carbon black. The variation in real and complex part of impedance with frequency has been studied as a function of filler and blowing agent loading. Additionally, the effect of crosslinking on the dielectric relaxation has also been reported. POLYM. ENG. SCI., 47:984,995, 2007. © 2007 Society of Plastics Engineers [source] AC impedance analysis and EMI shielding effectiveness of conductive SBR compositesPOLYMER ENGINEERING & SCIENCE, Issue 10 2006G.T. Mohanraj Flexible conductive polymer composites were prepared using styrene,butadiene rubber (SBR) as a matrix and conductive carbon black as filler. The filler loading was varied from 10 to 60 phr. The complex AC impedance and electromagnetic interference shielding effectiveness (EMI SE) of the composites were measured at the microwave frequencies of 7.8,12.4 GHz. The effect of variation in filler concentration and measurement frequency on the AC impedance and EMI SE of the composites were investigated. Equivalent circuits describing the conduction behavior of the composites were determined by means of Nyquist plots. The complex electric modulus of the composites was also determined. Increase in the filler loading increased the capacitive nature of the materials. The composites were better defined by a parallel resistor,capacitor circuit in series with a resistor. The EMI SE was found to pass through a maximum with increase in frequency. However, with the increase in filler loading and sample thickness of the material, the EMI SE was found to increase continuously. POLYM. ENG. SCI., 46:1342,1349, 2006. © 2006 Society of Plastics Engineers. [source] Production of electrically conductive networks in immiscible polymer blends by chaotic mixingPOLYMER ENGINEERING & SCIENCE, Issue 1 2006Dhawal P. Dharaiya A minor polymer was deformed into lamellar and fibrillar morphological forms in a chaotic mixer, which rendered the resultant immiscible blend electrically conductive along the flow direction. This was demonstrated using a blend consisting of 10 wt% polypropylene (PP), polyamide 6 (PA6), and 1 wt% conductive carbon black (CB) particles. It was found that PP-phase containing CB particles deformed into lamellar and fibrillar morphological forms produced continuous networks in the flow direction, and provided conductivity by double percolation. Breakup of PP fibrils into droplets destroyed the continuous conductive networks, although conductivity was sustained purportedly due to migration of CB particles from the bulk to the surface of closely spaced PP droplets. This was augmented by the formation of much smaller PP droplets in the presence of CB particles. On continued mixing, the blend eventually turned into insulator as CB particles migrated from the polymer,polymer interfaces to PA6 phase. POLYM. ENG. SCI., 46:19,28, 2006. © 2005 Society of Plastics Engineers [source] | ||||||||||