Topic
Acrylonitrile
About: Acrylonitrile is a research topic. Over the lifetime, 16517 publications have been published within this topic receiving 149835 citations. The topic is also known as: AN & Cyanoethylene.
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857 citations
TL;DR: In this article, the electrical conductivity of polyamide-6 and carbon nanotubes (NT) composites was analyzed and compared to carbon black filled polyamide 6 composites.
Abstract: Composites of polyamide-6 and carbon nanotubes (NT) have been prepared on a corotating twinscrew extruder. It is shown by transmission electron microscopy (TEM) that the nanotubes are dispersed homogeneously in the polyamide-matrix. The electrical conductivity of these composites was analyzed and compared to carbon black filled polyamide-6. It is found that the NT-filled polyamide-6 shows an onset of the electrical conductivity at low filler loadings (4–6 wt%). In agreement with rheological measurements this onset in the conductivity is attributed to a percolation of nanotubes in the insulating matrix polymer. Tensile tests of the NT-composites show a significant increase of 27% in the Young's modulus, however the elongation at break of these materials dramatically decreases due to an embrittlement of the polyamide-6. Blends of these composites and Acrylonitrile/butadiene/styrene (ABS) have been prepared by extrusion. It is shown by TEM measurements that the nanotubes are selectively located in the polyamide-6. These selectively filled polyamide-6/ABS-blends show a highly irregular, cocontinuous morphology. Due to the confinement of the conductive filler to one blend component these materials show an onset in the electrical conductivity at very low filler loadings (2–3 wt%). These findings are explained by a double percolation effect. The NT-filled blends show superior mechanical properties in the tensile tests and in IZOD notched impact tests.
695 citations
TL;DR: This Review gives an overview of precursor systems, their processing, and the final precursor-dependent structure of carbon fibers (CFs) including new developments in precursor systems for low-cost CFs.
Abstract: This Review gives an overview of precursor systems, their processing, and the final precursor-dependent structure of carbon fibers (CFs) including new developments in precursor systems for low-cost CFs. The following CF precursor systems are discussed: poly(acrylonitrile)-based copolymers, pitch, cellulose, lignin, poly(ethylene), and new synthetic polymeric precursors for high-end CFs. In addition, structure-property relationships and the different models for describing both the structure and morphology of CFs will be presented.
657 citations
DSM1
TL;DR: In kilogram quantities, pure poly(propylene imine) dendrimers can be prepared in an extremely simple reaction sequence comprising Michael addition (primary amines to acrylonitrile) and heterogeneous hydrogenation with a Raney cobalt catalyst.
Abstract: In kilogram quantities; pure poly(propylene imine) dendrimers can be prepared in an extremely simple reaction sequence comprising Michael addition (primary amines to acrylonitrile) and heterogeneous hydrogenation with a Raney cobalt catalyst. Both steps proceed quantitatively and selectively and can be employed with many core and end groups.
618 citations
TL;DR: The formation and evolution of structure, and the changes of properties during the preoxidation, precarbonization, and carbonization of different PAN precursors were studied by the combination of DSC, FT-IR, SEM and some traditional measurements, such as density and mechanical properties of various fibers as discussed by the authors.
Abstract: The formation and evolution of structure, and the changes of properties during the preoxidation, precarbonization, and carbonization of different PAN precursors were studied by the combination of DSC, FT-IR, SEM and some traditional measurements, such as density and mechanical properties of various fibers. The exothermic regime of polyacrylonitrile-based precursors made of acrylonitrile/itaconic acid (AN/IA) copolymers or acrylonitrile/acrylamide (AN/AM) copolymers is much broader and the cyclization reaction starts at lower temperature, compared to that of PAN homopolymer precursors, but AM appears to be more effective in separating the exothermic reactions corresponding to preoxidation stages in DSC curves as compared to IA. If AN/IA (97.5/2.5 w/w) precursors and AN/AM (97.5/2.5 w/w) precursors are designated as P1 and P2, respectively, the AM-containing commercial precursors (P3) are thermally more stable than the P2 ones, and the density of P3 is higher than that of P1 or P2. This may result from the difference of aggregation morphology among the original precursors, since it is dense for P3 precursors, whereas P2 and P1 precursors have some voids. The tensile strength of resultant carbon fibers from P3 precursors was better than that of carbon fibers from P2 or P1 after identical conditions of preoxidation are employed.
449 citations