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  • 1985-1989  (7)
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Materialart
Erscheinungszeitraum
Jahr
Schlagwörter
  • 1
    Digitale Medien
    Digitale Medien
    Resonant Raman scattering of controlled molecular weight polyacetylene (1988)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 89 (1988), S. 7615-7620 
    Details
    ISSN: 1089-7690
    Quelle: AIP Digital Archive
    Thema: Physik , Chemie und Pharmazie
    Notizen: Polyacetylene, (CH)x, films of 500, 5300, 10 500, and 100 000 Daltons number average molecular weights (Mn ) were synthesized using the titanium tetra-n-butoxide/triethyl aluminum-catalyst/cocatalyst system and examined using resonant Raman scattering techniques. Before isomerization, trans segments are found to exist mainly as short, isolated sequences independent of Mn. After thermal isomerization, theoretical analysis of the RRS spectra using the Brivio, Mulazzi model indicate the ratio of long trans conjugated segments (N≥30) to short trans conjugated segments (N≤30) is significantly larger for 100 000 Dalton polymer in comparison to polymer of 10 500 Mn and below. For samples below 10 500 Daltons, no clear relationship between actual polymer molecular weight and G is observed. Optimization of the isomerization conditions for 100 000 Dalton polymer results in trans-(CH)x with a G=0.80. These results suggest that not until very long molecular chains are obtained can samples composed principally of long conjugated segments be obtained. It is proposed that defects which arise during and after the polymerization limit the content of long segments. Ambient, short term oxidation of 100 000 Mn polymer shows a decrease in G from 0.80 to 0.70. Low level chain oxidation or doping is shown to preferentially occur within long conjugated segments.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1063/1.455248
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  • 2
    Digitale Medien
    Digitale Medien
    Rheology of a twin liquid crystalline polymer (1988)
    s.l. : American Chemical Society
    Macromolecules 21 (1988), S. 2014-2018 
    Details
    ISSN: 1520-5835
    Quelle: ACS Legacy Archives
    Thema: Chemie und Pharmazie , Physik
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1021/ma00185a022
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  • 3
    Digitale Medien
    Digitale Medien
    Miscibility of polymethacrylate/poly(vinyl chloride) blends (1989)
    s.l. : American Chemical Society
    Macromolecules 22 (1989), S. 1078-1083 
    Details
    ISSN: 1520-5835
    Quelle: ACS Legacy Archives
    Thema: Chemie und Pharmazie , Physik
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1021/ma00193a014
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  • 4
    Digitale Medien
    Digitale Medien
    Limits to compatibility in poly(x-methylstyrene)/poly(2,6-dimethylphenylene oxide) blends by NMR (1987)
    s.l. : American Chemical Society
    Macromolecules 20 (1987), S. 1757-1760 
    Details
    ISSN: 1520-5835
    Quelle: ACS Legacy Archives
    Thema: Chemie und Pharmazie , Physik
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1021/ma00174a007
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  • 5
    Digitale Medien
    Digitale Medien
    Acetylene-norbornene copolymers (1989)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 27 (1989), S. 3937-3949 
    Details
    ISSN: 0887-624X
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Metathesis ring opening polymerization has been used to copolymerize norbornene and 7,8-bis(trifluoromethyl)tricyclo[4,2,2,02,5]deca-3,7,9-triene. Subsequent thermal elimination of the precursor copolymers yielded acetylene-norbornene copolymers. The undoped copolymers were found to have electrical conductivity, spin concentration, and EPR linewidths which vary with composition. The location of the trans-C—H out-of-plane vibration, however, was invariant at 1010cm-1 indicating that conjugation length of n 〉 4 are present even at 40% acetylene content in the copolymer. The copolymers containing 79 mol % of acetylene units attained a doped conductivity of 0.02 S/cm with a dopant concentration of 6 mol % of I3- per sp2 carbon.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/pola.1989.080271206
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  • 6
    Digitale Medien
    Digitale Medien
    Thermal degradation of poly(4-methyl-1,3-dioxolane) (1989)
    Weinheim : Wiley-Blackwell
    Acta Polymerica 40 (1989), S. 586-590 
    Details
    ISSN: 0323-7648
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Beschreibung / Inhaltsverzeichnis: Die beim thermischen Abbau von Poly(4-methyl-1,3-dioxolan) gebildeten Verbindungen wurden durch gekoppelte Gaschromatographie und Massenspektrometrie analysiert. Zahlreiche Abbauprodukte auf Basis von Aldehyden, Ketonen, Alkoholen, Ethern und sauerstoffhaltigen cyclischen Verbindungen wurden erhalten. Die änderung der relativen Molekülmasse während des Abbaus wurde gemessen. Die Aktivierungsenergie für den Abbau des Polymers wurde bestimmt.
    Notizen: The products of degradation of poly(4-methyl-1,3-dioxolane) have been analyzed by combined gas chromatographymass spectroscopy. Numerous degradation products were observed based on aldehydes, ketones, alcohols, ethers, and oxygenated cyclic compounds. The changes of molecular weight during the degradation were determined. The activation energy of the degradation of the polymer was measured.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/actp.1989.010400908
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  • 7
    Digitale Medien
    Digitale Medien
    Radiolysis of resist polymers. VI. Copolymers of trihalophenylmethacrylate and methyl methacrylate (1985)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 23 (1985), S. 1421-1432 
    Details
    ISSN: 0360-6376
    Schlagwort(e): Physics ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Copolymers of several compositions of methyl methacrylate (MMA), trichlorophenyl methacrylate (TCPMA), and tribromophenyl methacrylate (TBPMA) have been synthesized and characterized. Gamma radiolysis yields are very sensitive to the presence of the halogenated monomers. With less than 10% of the halogenated monomer in the copolymers. Gs values were found to be much greater than that of PMMA. However, the halogenated monomer introduces a tendency toward crosslinking. The results are consistent with the enhancement of chain scission by dissociative electron capture and the tendency of phenyl radical intermediates to cause crosslinking. These structure-property relationships were found to be valid for all the homopolymers and copolymers investigated in this series.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/pol.1985.170230515
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