The Experts below are selected from a list of 42642 Experts worldwide ranked by ideXlab platform
M. Nagata - One of the best experts on this subject based on the ideXlab platform.
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Thermal degradation studies of poly(Vinyl Chloride) and ethylene-Vinyl Chloride copolymer
Journal of Analytical and Applied Pyrolysis, 1995Co-Authors: S. Mayeda, N. Tanimoto, H. Niwa, M. NagataAbstract:Abstract The thermal degradation behavior of suspension-polymerized poly(Vinyl Chloride) (PVC) and ethylene-Vinyl Chloride copolymer (E-VC) in the early stages was compared by continuous measurement of the extent of dehydrochlorination. The behavior of E-VC was different from that of PVC; the rate of dehydrochlorination of E-VC decreased as a function of heating time whereas that of PVC was constant. It was presumed that the dehydrochlorination reaction was terminated at the ethylene units in the polymer backbone. At a very early degradation stage, however, the rate of dehydrochlorination of E-VC was greater than that of PVC. This degradation behavior arose from structural defects in the polymer, i.e. the content of tertiary chlorine increased according to the increase in ethylene content in E-VC during suspension polymerization.
William H. Starnes - One of the best experts on this subject based on the ideXlab platform.
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Structural Defects in Poly(Vinyl Chloride) and the Mechanism of Vinyl Chloride Polymerization: Comments on Recent Studies
Procedia Chemistry, 2012Co-Authors: William H. StarnesAbstract:Abstract Investigations in the title areas within the past ten years are summarized and critiqued. The polymerizations studied were performed by conventional free-radical methods. A new mechanism, not yet confirmed, is suggested to explain a reported enhancement in the chloromethyl branch concentration of poly(Vinyl Chloride) (PVC) prepared at high conversions of monomer. This mechanism involves an intramolecular 1,5 hydrogen shift in a 1,3,5,6-tetrachlorohexyl radical. Evidence showing that most of the internal double bonds in PVC are not formed via intermolecular H abstraction from internal monomer units is tentatively rationalized, in part, by hydrogen transfer via at least one cyclic transition state containing more than eight members. The absence of free chlorine atoms from polymerizations of Vinyl Chloride (VC) is reaffirmed, and the copolymerization of VC with the chloroallylic chain ends of PVC is argued to be insignificant. New information in the literature does not invalidate the currently accepted mechanism of Vinyl Chloride polymerization.
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Structural defects in poly(Vinyl Chloride)
Journal of Polymer Science Part A: Polymer Chemistry, 2005Co-Authors: William H. StarnesAbstract:This article describes, in narrative style, the research of the author and his associates, performed over a period of 30 years, that led to the identification and quantification of the anomalous structures in poly(Vinyl Chloride) (PVC) and to detailed descriptions of their mechanisms of formation. Also examined here are the implications of this work for the thermal stability of PVC, for the overall chemical mechanism of Vinyl Chloride polymerization, and for other relevant aspects of the chemistry and technology of Vinyl Chloride homopolymers and copolymers. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 2451–2467, 2005
Masatoshi Nagata - One of the best experts on this subject based on the ideXlab platform.
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Determination of Short-Chain Branches in Poly(Vinyl Chloride) and Ethylene- Vinyl Chloride Copolymers by Pyrolysis-Hydrogenation-Gas Chromatography
Polymer Journal, 1999Co-Authors: Shuncong Mao, Hajime Ohtani, Shin Tsuge, Hiroshi Niwa, Masatoshi NagataAbstract:Determination of Short-Chain Branches in Poly(Vinyl Chloride) and Ethylene-Vinyl Chloride Copolymers by Pyrolysis-Hydrogenation-Gas Chromatography
S. Mayeda - One of the best experts on this subject based on the ideXlab platform.
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Thermal degradation studies of poly(Vinyl Chloride) and ethylene-Vinyl Chloride copolymer
Journal of Analytical and Applied Pyrolysis, 1995Co-Authors: S. Mayeda, N. Tanimoto, H. Niwa, M. NagataAbstract:Abstract The thermal degradation behavior of suspension-polymerized poly(Vinyl Chloride) (PVC) and ethylene-Vinyl Chloride copolymer (E-VC) in the early stages was compared by continuous measurement of the extent of dehydrochlorination. The behavior of E-VC was different from that of PVC; the rate of dehydrochlorination of E-VC decreased as a function of heating time whereas that of PVC was constant. It was presumed that the dehydrochlorination reaction was terminated at the ethylene units in the polymer backbone. At a very early degradation stage, however, the rate of dehydrochlorination of E-VC was greater than that of PVC. This degradation behavior arose from structural defects in the polymer, i.e. the content of tertiary chlorine increased according to the increase in ethylene content in E-VC during suspension polymerization.
Irving J. Selikoff - One of the best experts on this subject based on the ideXlab platform.
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Mortality experience of a cohort of Vinyl Chloride-polyVinyl Chloride workers.
Annals of the New York Academy of Sciences, 2006Co-Authors: William J. Nicholson, E. Cuyler Hammond, Herbert Seidman, Irving J. SelikoffAbstract:These data are derived from early follow-up of individuals exposed for 5 or more years to Vinyl Chloride in a polymerization facility. At least 17 percent of the deaths that occurred were causally related to exposure to Vinyl Chloride. Longer periods of observation are required to provide information concerning the full spectrum of Vinyl Chloride-induced malignancies and their incidence among exposed workers. These data speak for the need to prevent exposure to Vinyl Chloride and for surveillance and early disease detection of those who have experienced Vinyl Chloride exposures in the past.
