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  • Polymer and Materials Science  (25)
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  • 1
    Electronic Resource
    Electronic Resource
    Infrared and Raman spectroscopy of carbohydrates. Part VI: Normal coordinate analysis of V-amylose (1975)
    New York : Wiley-Blackwell
    Biopolymers 14 (1975), S. 1885-1903 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A normal coordinate analysis of V-amylose has been performed for an isolated 61 helical chain. Negligible splitting from interactions of vibrations of successive residues is expected between A and E vibrational species due to the large size of the monomer unit. As a result, calculation of only the totally symmetric A modes represents an adequate approximation to the vibrational spectrum of helical polysaccharides. Using this method together with a valence force field we have obtained good agreement between the observed and calculated frequencies. In addition, the computed potential energy distribution and Cartesian displacement coordinates match previous experimental assignments, based on deuterium exchange. The analysis also supports the proposed mechanism for conversion of V-amylose to the more extended B-form. This conversion results in an observed frequency shift for the Raman line at 946 cm-1 which is predicted by the calculations.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1975.360140909
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  • 2
    Electronic Resource
    Electronic Resource
    Raman scattering of collagen, gelatin, and elastin (1975)
    New York : Wiley-Blackwell
    Biopolymers 14 (1975), S. 379-391 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The Raman spectra of collagen, gelatin, and elastin are presented. The Raman lines in the latter two spectra are assigned by deuterating the amide N-H groups in gelatin and by studying the superposition spectra of the constituent amino acids. Two lines appear at 1271 and 1248 cm-1 in the spectra of collagen and gelatin that can be assigned to the amide III mode. Possibly, the appearance of two amide III lines is related to the biphasic nature of the tropocollagen molecule, i.e., proline-rich (nonpolar) and proline-poor (polar) regions distributed along the chain. The melting, or collagen-to-gelatin transition, in water-soluble calf skin collagen is studied and the 1248-cm-1 amide III line is assigned to the 31 helical regions of the tropocollagen molecule.Elastin is thought to be mostly random and the Raman spectrum confirms this assertion. Strong amide I and III lines appear at 1668 and 1254 cm-1, respectively, and only weak scattering is observed at 938 cm-1. These features have been shown to be characteristic of the disordered conformation in proteins.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1975.360140211
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    A fourier transform infrared and nuclear magnetic resonance study of cyclized natural rubber (1987)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 188 (1987), S. 2325-2337 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Fourier transform infrared (FTIR), 1H NMR, and 13C NMR have been used to characterize the structure of natural rubber cyclized with p-toluenesulfonic acid. The samples studied were only partially cyclized. The cyclized portions contained both mobile and rigid domains. Crosslinking occurred during the cyclization reaction. The cyclized samples showed a distribution of functionalities including some oxidation products. All three types of olefinic segmented end groups were formed during cyclization (di-, tri-, and tetrasubstituted olefins). The loss of the exocyclic species leads to the formation of cross-linked networks.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1987.021881009
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  • 4
    Electronic Resource
    Electronic Resource
    Solid-state 13C NMR studies of vulcanized elastomers, 4.Part 3: cf.16. Sulfur-vulcanized polybutadieneDedicated to Prof. H. J. Cantow on the occasion of his 65th birthday (1988)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 189 (1988), S. 1239-1251 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The sulfur vulcanization of cis-1,4-polybutadiene was studied by solid-state 13C NMR spectroscopy. Polybutadiene is cured with several different formulations including sulfur and accelerators in order to determine the network structure of the resulting vulcanizates. Polysulfidic crosslinks bound to the methylene carbons of the polybutadiene repeating unit were observed in the rubber network. Cyclic sulfide structures were detected in the network structure in addition to cis-to-trans chain isomerization. Two different pulse sequences were used for the NMR experiments of the sulfur-vulcanized cis-polybutadiene. The gated high power decoupling NMR experiment reflects the mobile regions of the vulcanizate sample while the cross polarization pulse sequence reflects the regions of the sample which are inherently more rigid. The cross polarization spectra of the samples cured with high sulfur levels showed that a considerable amount of rigidity is found in the vulcanized cis-polybutadiene network. It was also possible to obtain cross polarization spectra of the lightly crosslinked polybutadiene vulcanizates. This is in contrast to the NMR results of the vulcanized natural rubber systems which generally tended to have considerably more mobility.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1988.021890602
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  • 5
    Electronic Resource
    Electronic Resource
    Magic-angle 13C NMR spectroscopy of chloral polymersDedicated with best personal regards to Prof. Cantow on the occasion of his 60th birthday (1983)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 184 (1983), S. 1243-1246 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The homopolymer of chloral and a copolymer of chloral and p-chlorophenyl isocyanate were studied by magic-angle 13C NMR spectroscopy. 13C NMR Measurements with magic-angle spinning and cross polarization show for the acetal carbon a chemical shift of 101, 4 p.p.m. downfield from tetramethylsilane. The observation of a symmetrical, reasonably sharp (3 p.p.m.) resonance suggests that the polychloral is stereoregular. Spectra of chloral copolymers with 5 moles percent p-chlorophenyl is steroregular. Spectrical of chloral copolymers with 5 moles percent p-chlorophenyl isocynate have additional peaks between 130 and 150 p.p.m. from the aromatic carbons of the p-chlorophenyl isocyanate moiety.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1983.021840613
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  • 6
    Electronic Resource
    Electronic Resource
    The solution conformation of poly(L-lysine). A Raman and infrared spectroscopic study (1976)
    New York : Wiley-Blackwell
    Biopolymers 15 (1976), S. 229-240 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The Raman and infrared spectra of poly(L-lysine) and poly(DL-lysine) in solution are reported and the effects of various salts are investigated. The results demonstrate that α-helix formation in solution is induced by specific salts and the spectral data support the hypothesis of regions of local order for poly(L-lysine) in aqueous solutions of low ionic strength.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1976.360150202
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  • 7
    Electronic Resource
    Electronic Resource
    Solid-state carbon-13 NMR Studies of vulcanized elastomers. V. Observation of new structures in sulfur-vulcanized natural rubber (1989)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 27 (1989), S. 1389-1404 
    Details
    ISSN: 0887-6266
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The complementary application of the NMR inversion recovery measurements and the computer fitting of the overlapping spectral region is found to be a useful method for structural analysis of vulcanized natural rubber in the solid state. Since the linewidths in 13C-NMR spectra of solids are relatively broad compared with the differences between chemical shifts, some weak signals are completely obscured in the resulting spectra. If the resonances have sufficiently different relaxation times, such as methyl and methylene carbons, it is possible to detect neighboring heavily overlapped signals by using the inversion recovery delay τ value at which the interfering strong resonance has null intensity. The 20 resonances observed in the spectra of crosslinked rubbers are tentatively assigned to the structural units formed during the vulcanization process. It is found that vulcanizates containing smaller amounts of sulfur (1 and 3%) show insignificant changes in the NMR spectra for curing times of 30 and 90 min. Structural modifications in rubbers cured with 10% sulfur continuously increase with the increasing curing time up to 120 min, indicating a significant loss in double bonds in the later stages of the reaction.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/polb.1989.090270702
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  • 8
    Electronic Resource
    Electronic Resource
    Relaxation processes and molecular motion in a new semicrystalline polyimide (1995)
    Weinheim : Wiley-Blackwell
    Macromolecular Chemistry and Physics 196 (1995), S. 1439-1451 
    Details
    ISSN: 1022-1352
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A new polymide was synthesized from 3,3′,4,4′-benzophenonetetracarboxylic dianhydride (BTDA) and 2,2-dimethyl-1,3-(4-aminophenoxy)propane (DMDA), and abbreviated to be BTDA-DMDA. This polymer possesses three relaxation processes which have been observed through dynamic mechanical and dielectric analyses above-150°C. The α relaxation process has been assigned to be the glass transition and occurs at about 250°C with an apparent activation energy of 420kJ/mol. Two subglass relaxation processes are a β relaxation process at around 100-170°C in a frequency range from 0,1 Hz to 100 kHz with an activation energy of 182 kJ/mol and a γ relaxation process occurs at around -80°C with an activation energy of 44 kJ/mol. Carbon-13 solid state nuclear magnetic resonance experiments were carried out for the study of molecular dynamics at different temperatures. The results indicate that the γ relaxation is responsible for an oscillation and π flipping motion of the two phenoxy rings in the DMDA portion. The β relaxation was shown to pertain to the kHz-motion of the aromatic imide rings in the BTDA portion. The molecular motion of the DMDA and BTDA protions are largely decoupled from each other in the frequency region studied.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1995.021960507
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  • 9
    Electronic Resource
    Electronic Resource
    Reinforcement mechanism of polyester-fiber-reinforced rubber - A model study (1983)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 28 (1983), S. 2633-2646 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The reinforcement mechanism of polyester tire cord was studied by Fourier-transform infrared spectroscopy using various model compounds. Three model compounds representing the main chain of polyester and the terminal groups, namely carboxylic acid and hydroxyl groups, were used. Chemical reactions between these polyester models and an epoxy functional silane coupling agent were studied qualitatively as well as quantitatively. Among the many possible reactions, the reaction between the carboxylic acid and epoxy group was found to proceed readily. Kinetic studies of the major reactions also show quantitative differences in their activation energies as well as the rate constants. Based on the quantitative studies, we have estimated the expected rate of interfacial reaction at the heat treating temperature of polyester tire cord.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1983.070280815
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  • 10
    Electronic Resource
    Electronic Resource
    Stereoregularity of PVC studied by 13C NMR (1980)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 25 (1980), S. 2205-2210 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The proton decoupled 13C NMR spectra of PVC polymerized at various temperatures were obtained using a 150-MHz NMR spectrometer. Chemical shift changes induced by a solvent effect were utilized to allow the detection of the six possible tetrads. Eight of ten possible pentads were also observed. The relative areas of tetrads and triads indicate that the polymerization of PVC above -20°C is Bernoullian.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1980.070251007
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