CB Content (cb + content)

Distribution by Scientific Domains
Polymers and Materials Science100%

Selected Abstracts

Electrical Response to Organic Vapor of Conductive Composites from Amorphous Polymer/Carbon Black Prepared by Polymerization Filling

MACROMOLECULAR MATERIALS & ENGINEERING, Issue 2 2003
Jun Rong Li
Abstract In recent years, conductive polymer composites have found applications as gas sensors because of their sudden change in electric resistance of several orders of magnitude when the materials are exposed to certain solvent vapors. However, the composites having this function reported so far are mostly based on crystalline polymeric matrices, which factually sets a limit to materials selection. The present work prepares polystyrene/carbon black composites through polymerization filling and proves that the amorphous polymer composites can also serve as gas sensing materials. The composites' percolation threshold is much lower than that of the composites produced by dispersive mixing. In addition, high responsivity to some organic vapors coupled with sufficient reproducibility is acquired. The experimental data show that molecular weight and molecular weight distribution of the matrix polymer and conducting filler content exert great influence on the electrical response behavior of the composites. As a result, composites performance can be purposely tailored accordingly. Compared with the approaches of melt-blending and solution-blending, the current technique is characterized by many advantages, such as simplicity, low cost, and easy to be controlled. Effect of different organic solvent vapors on the electric resistance of PS/CB composites (CB content,=,10.35 vol.-%). [source]

New antistatic charge and electromagnetic shielding effectiveness from conductive epoxy resin/plasticized carbon black composites

POLYMER COMPOSITES, Issue 2 2008
Nadia Abdel Aal
Recently, there is an increasing interest in electromagnetic interference shielding due to the rapid increase in electromagnetic pollution and the wide use of commercial and military products. Conducting polymer composites were prepared in the presence of epoxy resin and plasticized carbon black (CB). The structural characteristics of the composites were examined by means of scanning electron microscopy, cross linking density, and interparticle distance among conductive particles. The mechanical properties such as Young's modulus, elongation at break, and hardness of the composites were investigated as a function of CB content. The results indicated that CB could improve the composite microstructure. The higher mechanical behavior than green epoxy can be attributed to the interaction between CB particles and epoxy resin. The conductivity, mobility carriers, and number of charges of the composites at room temperature were found to be dependent on CB content. The applicability of the composites to antistatic charge dissipation was examined. Dependence of the microwave properties of the epoxy/CB composites on the volume fraction of CB particles and frequency were studied. Moreover the permittivity as a function of frequency of the composites was studied. The electromagnetic wave shielding of epoxy/CB composites is dominant by both reflection and absorption. Composites can find applications in antistatic charge dissipation and in suppression of electromagnetic interference and stealth technology. POLYM. COMPOS., 2008. © 2007 Society of Plastics Engineers [source]

Carbon black filled PET/PMMA blends: Electrical and morphological studies

POLYMER ENGINEERING & SCIENCE, Issue 10 2000
J. G. Mallette
In this work, the electrical and morphological properties of blends of poly(ethylene terephthalate) (PET), poly(methyl methacrylate) (PMMA), and carbon black (CB) were analyzed. Resistivity decreases similarly in both PET and PMMA with CB concentration. Similarly in the PET/PMMA blend, extensive modification to this behavior occurs, since resistivity becomes a function of morphology and specific location of CB in the polymers. A minimum in the resistivity of the blend with 5% CB (PET basis) is observed at 100% PET, whereas with an increase in the CB content to 20%, the minimum in the resistivity shifts to 60% PET. High conductivity is observed when PET is the continuous phase (having the larger viscosity). Large stresses lead to a large dispersion of CB and a high deformation and rupture of the dispersed PMMA phase. This situation itself promotes an increase of surface area of droplets and high CB concentrations at the interface. Consideration is given to models that predict a selective location of conductive particles in the PET matrix based on its lower interfacial tension with CB. [source]

Partially miscible poly(lactic acid)- blend -poly(propylene carbonate) filled with carbon black as conductive polymer composite

POLYMER INTERNATIONAL, Issue 9 2008
Wang Ning
Abstract BACKGROUND: Conductive polymer composites (CPCs) can be obtained by filling polymer matrices with electrically conductive particles, and have a wide variety of potential applications. In the work reported, the biodegradable polymer poly(lactic acid) (PLA) as a partially miscible blend with poly(propylene carbonate) (PPC) was used as a polymer matrix. Carbon black (CB) was used as the conducting filler. RESULTS: Fourier transform infrared spectroscopy revealed interactions between matrix and CB filler; this interaction was stronger in PPC- blend -CB than in PLA- blend -CB composites. A rheology study showed that low-viscosity PPC could improve the fluidity of the CPCs, but decrease that of CB. With increasing CB content, the enforcement effect, storage modulus and glass transition temperature increased, but the elongation at break decreased. CPCs exhibited the lowest electrical percolation thresholds of 1.39 vol.% CB when the content of PPC in PLA- blend -PPC was 40 wt%. The conductivity of CPCs containing 5.33 vol.% CB and 40 wt% PPC reached 1.57 S cm,1. Scanning electron microscopy revealed that CB exhibits a preference for dispersion in the low-viscosity phase (PPC) of the multiphase matrix. CONCLUSION: In the presence of CB, partially miscible PLA- blend -PPC could form multi-percolation CPCs. Moreover, the combination of PLA and PPC with CB broadens novel application of both renewable polymers and CPCs. Copyright © 2008 Society of Chemical Industry [source]

Formation of in situ CB/PET Microfibers in CB/PET/PE Composites by Slit Die Extrusion and Hot Stretching

MACROMOLECULAR MATERIALS & ENGINEERING, Issue 6 2004
Xiang-Bin Xu
Abstract Summary: In this present study, the in situ fabrication of a microfibrillar composite based on poly(ethylene terephthalate) (PET), polyethylene (PE), and carbon black (CB) is attempted. PET and CB were first melt mixed. The CB/PET compound and PE were subsequently melt extruded through a slit die and then hot stretched. The morphological observation of the as-stretched extrudate indicated that well-defined microfibers of CB/PET compound could be generated at appropriate CB contents and a fixed hot stretch ratio. In addition, CB was always selectively located in PET. The microfibrillar CB/PET/PE composite has the potential to be a new electrically conductive polymer composite. Morphology of the carbon black/poly(ethylene terephthalate)/polyethylene (PE) composite after additional mixing in the mixer at the processing temperature of PE. [source]