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  • Articles  (46)
  • Polymer and Materials Science  (36)
  • Inorganic Chemistry  (9)
  • Biochemistry and Biotechnology  (1)
  • High resolution GC-MS
  • Wiley-Blackwell  (46)
  • 1985-1989  (46)
  • 11
    Electronic Resource
    Electronic Resource
    Tacticity and dielectric relaxation around the glass transition of poly(vinyl chloride). A thermally stimulated depolarization currents (TSDC) study (1989)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 190 (1989), S. 893-905 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The thermally stimulated depolarization currents (TSDC) technique has been used to study molecular motions around the glass transition in three different samples of poly(vinyl chloride) (PVC) varying in the contents of isotactic triads. The α-relaxation mode associated with cooperative molecular motions taking part in glass transition appears to be strongly dependent on tacticity. A secondary relaxation mode α′, different from the β-relaxation, has been detected just below the α-relaxation and at temperatures depending on the content of isotactic triads. Above the glass transition temperature the TSDC curves show a ρ-peak corresponding to the motion of free charges in the material. This process does not seem to be affected by tacticity. The results suggest that specific conformations of isotactic triads play an important role in the motion of chain segments in the polymer.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1989.021900422
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  • 12
    Electronic Resource
    Electronic Resource
    On the preferential extraction of the more isotactic parts of PVC with acetone. A verification by 13C NMR analysis (1986)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 187 (1986), S. 2649-2653 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Acetone-soluble and -insoluble fractions were obtained from two different PVC samples: a polymer prepared in our laboratory at 60°C using 2,2′-azoisobutyronitrile (AIBN) as initiator (sample A) and a commercial polymer prepared at 70°C (sample B). The content of isotactic, syndiotactic and heterotactic traids was accurately measured by high resolution 13C NMR. From the obtained data it follows that the isotactic triads accumulate preferably in the soluble fraction, the amount of which depends on the type of polymer. In agreement with earlier results, the soluble fraction is about 40% less stable than the insoluble fraction. The reasons for this behaviour are discussed in the light of the higher content of both isotactic triads and some defect structures, as found in the low molecular weight soluble extracts of PVC.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1986.021871114
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  • 13
    Electronic Resource
    Electronic Resource
    Properties of polyacetylene obtained with (η-Cp)2Ti(PMe3)2 (1989)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 190 (1989), S. 1309-1317 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Acetylene was polymerized by (η-Cp)2Ti(PMe3)2 at room temperature to give predominantly trans-polyacetylene. All properties are within the ranges reported for polyacetylene produced with Ti(OBu)4/AlEt3 as catalyst.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1989.021900611
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  • 14
    Electronic Resource
    Electronic Resource
    Structural analysis of poly(3-alkylthiophene)s (1989)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 190 (1989), S. 3105-3116 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Poly(3-hexylthiophene) (PT6), poly(3-octylthiophene) (PT8), poly(3-decylthiophene) (PT10) and poly(3-dodecylthiophene) (PT12) were synthesized by electrochemical and chemical polymerization. Investigation of these polymers by means of gel permeation chromatography indicates that the polymers prepared from the different monomers under similar conditions do not differ substantially considering molecular weight and molecular weight distribution. Bimodal distributions were found for electropolymerized polymers, and with increasing polymerization time, the high-molecular-weight and probably highly branched fraction increased relatively to the low-molecular-weight fraction. The microstructure of the polymers was investigated by nuclear magnetic resonance, and it has been found that the polymers exhibit more types of structural units than expected from a simple coupling of adjacent thiophene moieties in 2,5′-positions. Chemical oxidation with iron trichloride in chloroform gave soluble, high-molecular-weight poly(3-alkyl-thiophene)s with a rather low amount of irregular couplings, and these more regular polymers exhibited a higher degree of crytallinity. Room temperature conductivities of the oxidized polymers were between 0,1 and 30 S/cm depending on the polymerization conditions, but these values were rather independent of the length of the alkyl substituent.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1989.021901208
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  • 15
    Electronic Resource
    Electronic Resource
    Tacticity and dielectric relaxation around the glass transition of poly(vinyl chloride), a dynamic-dielectric study (1989)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 190 (1989), S. 3257-3267 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Molecular motions of poly(vinyl chloride) (PVC) in the glass transition range were studied by means of dielectric spectroscopy. The measurements were carried out with three different PVC samples obtained at different polymerization temperatures (0, 60 and 90°C) showing strong variations in their contents of syndiotactic, heterotactic and isotactic triads. The results show that all parameters (relaxation strength, temperature of the maxima of loss curves, evolution of the shift factors, master curves) characterizing the dielectric α-relaxation in the liquid state of PVC are strongly affected by the tacticity. These facts are interpreted in terms of the role of specific local conformations in the motion of chain segments in the polymer molecules. These conclusions are in agreement with those outlined from the results previously obtained on PVC for the molecular motions in the glassy state just below the glass transition temperature.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1989.021901223
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  • 16
    Electronic Resource
    Electronic Resource
    Dissociation constant of poly(ethylene oxide) macroion pairs in nitrobenzene (1986)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 187 (1986), S. 1367-1370 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The great stability of the cationic polymerization system, ethylene oxide/nitrobenzene, from an electrochemical point of view, was investigatd as well as the assumption that the stable salts of triphenylmethylium and the macroion pair have the same dissociation constant. The value was determined to be 9,4 · 10-3 mol · 1-1 at 293 K in nitrobenzene.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1986.021870605
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  • 17
    Electronic Resource
    Electronic Resource
    Dependence of glass-transition temperature Tg on tacticity of poly(vinyl chloride). A preliminary study by differential scanning calorimetry (1988)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 189 (1988), S. 567-572 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The glass-transition temperature, Tg, of poly(vinyl chloride) (PVC) has been found to depend linearly on both the overall isotactic triad content and a small fraction of isotactic triads. It was previously demonstrated, that the latter react with sodium benzenethiolate at temperatures as low as -30°C, probably because they adopt a definite local conformation. In general, it was believed before that the tacticity effect on Tg occurs only for disubstituted C—C-polymers, the results obtained in this work for PVC would suggest that specific conformations of isotactic triads can also enhance the motion of chain segments in the polymer.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1988.021890310
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  • 18
    Electronic Resource
    Electronic Resource
    Quantitative evaluation of soluble polymeric photosensitizers, 4Parts 1-3: cf.5-7. Trans-cis isomerization of stilbene photosensitized by polymerbound o- and p-benzyloxybenzaldehyde (1987)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 188 (1987), S. 1703-1711 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The grafting of o- and p-benzyloxybenzaldehyde onto linear chloromethylated polystyrene is described. The resulting soluble polymeric photosensitizers and their model compounds, o- and p-(p-isopropylbenzyloxy)benzaldehyde, were tested as triplet energy donors against trans-stilbene in benzene solution. Irradiation of the ortho-compounds gives rise to a transformation which has been tentatively attributed to an intramolecular photocyclization. Stern-Volmer constants for the photostable para-compounds were determined. Results for both types of compounds show that the sensitizer efficiency diminishes when it is bound to the polymer.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1987.021880717
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  • 19
    Electronic Resource
    Electronic Resource
    Influence of the structure on the photodegradation of poly(vinyl chloride), 3.Part 2: cf.5. Dependance of the quantum yield of dehydrochlorination on the isotactic content (1989)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 190 (1989), S. 477-485 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The photodehydrochlorination of four poly(vinyl chloride) (PVC) samples of different tacticities, as studied previously, was compared with that of a PVC sample after being modified to various degrees by nucleophilic substitution with sodium benzenethiolate (NaBT). In order to separate the influence of substituted structures from that of the chromophoric group grafted onto the polymer, a series of PVC mixtures with sec-butyl phenyl sulfide (BPT), of compositions similar to those of modified polymers was also studied. The evolution of HCl was found to be a linear function of the absorbed dose in all cases. The quantum yield of dehydrochlorination, ΦHCl, as obtained from the slopes, appeared to decrease with the isotactic content. The results suggest specific isotactic triads to be markedly reponsible for the photodehydrochlorination, which would account for a mechanism based on the occurrence of chlorines of low dissociation energy at such triads.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1989.021900304
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  • 20
    Electronic Resource
    Electronic Resource
    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
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 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.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1989.080271206
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