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  • Polymer and Materials Science  (180)
  • Physics  (24)
  • Chemical Engineering  (21)
  • 1
    Digitale Medien
    Digitale Medien
    Analysis of fluorinated polymers: Several approaches by wide-line nuclear magnetic resonance (1989)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 190 (1989), S. 2815-2819 
    Details
    ISSN: 0025-116X
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Notizen: Two different ways of analyzing the composition of insoluble, partly hydrogenated, partly fluorinated copolymers by NMR are described. The first relies on a quantitative comparison of 1H and 19F free induction decays, as observed in the solid state, with those of reference samples. The second relies on medium resolution spectra which can be achieved, thanks to the large scale of 19F chemical shifts, on softening of the samples at high temperature. A special probe working up to 400°C was built for this purpose. The two methods are in good agreement in the case of vinylidene fluoride (VF2)/tetrafluoroethylene (VF4) copolymers, leading to a determination of the rectivity ratios; the special usefulness of the second method is illustrated by the identification of a third comonomer in VF2/VF4 terpolymers.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/macp.1989.021901113
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  • 2
    Digitale Medien
    Digitale Medien
    Stretching and overstretching of DNA in pulsed field gel electrophoresis. I. A quantitative study from the steady state birefringence decay (1993)
    New York : Wiley-Blackwell
    Biopolymers 33 (1993), S. 1347-1357 
    Details
    ISSN: 0006-3525
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Using a sensitive birefringence instrument, the birefringence arising from the orientation of the DNA chain during electrophoretic transport has been recorded. This birefringence is shown to proceed both from the alignment (stretching) of the molecule in the direction of the electric field and from the extension of the length of its primitive path (overstretching). The contribution of these two processes can be separated in the decay of the birefringence after the end of the application of the electric field. The fast relaxation of the overstretching occurs first and is demonstrated to be the main contribution to the birefringence. The orientation factor of the remaining stretched state and its decay can be quantitatively understood using the biased reptation model. It provides, in addition, a high value for the tube diameter or gel pore size a (4500 ± 450 Å for a 0.7% agarose gel with a c-0.6g dependence in the agarose concentration cg) and a low value for the effective charge per base pair (0.2e as compared to 0.5e using the condensation hypothesis). The contribution of overstretching to the birefringence is also quantitatively interpreted in term of the change in the mean length l of DNA inside a pore size a. The dynamics of decay of this overstretching is well represented by a stretched exponential with a stretching exponent α = 0.44. The mean decay time decreases slightly with increasing fields and scales with the overall DNA length close to N20. © 1993 John Wiley & Sons, Inc.
    Zusätzliches Material: 14 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bip.360330905
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  • 3
    Digitale Medien
    Digitale Medien
    Surface treatment of an epoxy resin by CO2 laser irradiation (1996)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 238 (1996), S. 177-189 
    Details
    ISSN: 0003-3146
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Beschreibung / Inhaltsverzeichnis: Der Einfluß von CO2-Laserstrahlung auf die Oberflächeneigenschaften eines Epoxid-Laminierharzes (wärmebeständig bis 120°C) für kohlefaserverstärkte Kunststoffe (CFK) wird untersucht. Infrarot- und XPS-Spektroskopie zeigen, daß die Hydroxygruppen des Harzes unter Bildung von Doppelbindungen eliminiert werden. In Kohlendioxidatmosphäre werden tiefer liegende Teile des Harzes modifiziert als bei der Behandlung in Luft. Eine Steigerung der Reproduzierbarkeit der Klebfestigkeit des verwendeten CFK auf Basis des untersuchten Harzes ist nur bei gleichzeitiger Verringerung der Klebfestigkeit selbst möglich. Beim Einsatz eines heißhärtenden Klebstoffes kann kein Einfluß der Laserbehandlung auf die Klebfestigkeit festgestellt werden.
    Notizen: The influence of CO2 laser radiation on the surface properties of a lamination resin (temperature resistant up to 120°C) which is used for carbon fibre-reinforced plastics (CFRP) is examined. It is shown by XPS and infrared spectroscopy that the hydroxy groups of the resin are eliminated by the laser radiation. Using a carbon dioxide atmosphere, also deeper parts of the resin are influenced compared to the treatment in air. The reproducibility of the bond strength is higher for the laser-treated samples than for untreated samples if a room temperature-curing adhesive is used, but the bond strength itself is lower. Laser treatment shows no influence at all if a hot-curing adhesive is used.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/apmc.1996.052380115
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  • 4
    Digitale Medien
    Digitale Medien
    Random copolymers of α-benzyl-L-aspartate with ortho- and para-nitrobenzyl-L-aspartates. Intrinsic and extrinsic dichroic bands and the left-to-right-handed α-helical transition (1975)
    New York : Wiley-Blackwell
    Biopolymers 14 (1975), S. 469-485 
    Details
    ISSN: 0006-3525
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Copolymers of benzylaspartate with the corresponding para-nitro and ortho-nitro derivatives are known to undergo, at increasing nitro content, a transition from a left-handed α-helical conformation to a right-handed α-helical conformation. The circular dichroism associated with the n, π* transition of the amide group, as well as the extrinsic bands associated with the nitrobenzyl chromophore, have been studied for these copolymers as a function of the nitro content. The circular dichroism associated with the 330-nm extrinsic band is shown to present an abrupt change, which parallels the change in the 222-nm band characteristic of the left- to right-handed helix transition. The intensity of the 222-nm CD band seems unaffected by the interaction with the side-band chromophore. The circular dichroism associated with the 330-nm band is much stronger in the right-handed conformation and is unaffected by increasing interactions between side chains. Interpretation in the light of the possible mechanism for optical activity of helical molecules seems to indicate that the 330-nm extrinsic effect is essentially due to the Condon, Altar, and Eyring (CAE) mechanism and μ-m perturbation (in Schellmann terminology) on the side-chain chromophore n, π* transition.
    Zusätzliches Material: 9 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bip.1975.360140304
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  • 5
    Digitale Medien
    Digitale Medien
    Stretching and overstretching of DNA in pulsed field gel electrophoresis. II. Coupling of orientation and transport in initial response to the field (1993)
    New York : Wiley-Blackwell
    Biopolymers 33 (1993), S. 1359-1363 
    Details
    ISSN: 0006-3525
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The rise of the birefringence following the application of an electric field to DNA in an agarose gel has been quantitatively analyzed to demonstrate the major role played by the chain overstretching. By analyzing the field free decay after short times, we demonstrate that the overshoot is completely due to overstretching. Its time of appearance τov varies with the field and DNA length in fair agreement with the E-lN0ln N0 prediction of Lim et al. [ (1990), Journal of Chemical Physics, Vol. 92, pp. 709-721]. The τov is also the time corresponding to one tube renewal after relaxation of the overstretching. © 1993 John Wiley & Sons, Inc.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bip.360330906
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  • 6
    Digitale Medien
    Digitale Medien
    Synthèse par voie radicalaire de polymères à extrémités hydroxylées 4.Partie 3: cf.11. Polymérisation et copolymérisation de butènes (1976)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 177 (1976), S. 2877-2896 
    Details
    ISSN: 0025-116X
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Beschreibung / Inhaltsverzeichnis: The homopolymerization of 1-butene, 2-butene, and isobutene in methanol initiated by hydrogen peroxide affords low molecular weight hydroxylated oligomers in low polymerization yields. The copolymerization of these monomers with a diene monomer such as butadiene can easily be carried out. The reactivity ratios were found to depend on the structure of the monomers; the polymerization and copolymerization rate of 2-butene being higher than those of isobutene, but lower than those of 1-butene.
    Notizen: L'homopolymérisation dans le méthanol des butène-1, butène-2 et isobutène amorcée par l'eau oxygénée conduit à la formation, avec de faibles taux de conversion, de polymères de faibles ou de très faibles masses moléculaires comportant des fonctions hydroxyles. La copolymérisation de ces éthyléniques avec un monomère diènique, tel que le butadiène, s'effectue facilement. Les constantes de réctivité ont été déterminées. Elles sont liées aux structures des monomères: le butène-2 polymérise et copolymérise mieux que l'isobutène mais moins bien que le butène-1.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/macp.1976.021771006
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  • 7
    Digitale Medien
    Digitale Medien
    Synthèse par polymérisation anionique de copolymères biséquencés polybutadiène-poly(vinyl-2 naphtalène). Étude de leur structure en solution concentrée avant et après polymérisation du solvant (1976)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 177 (1976), S. 2945-2962 
    Details
    ISSN: 0025-116X
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Beschreibung / Inhaltsverzeichnis: Block copolymers polybutadiene-poly(2-vinylnaphthalene) (BVN) were prepared by anionic polymerization in vacuum. The choice of polymerization conditions in order to obtain monodisperse block copolymers are discussed. Using low angle X ray diffraction electron microscopy, the structure of the mesophases was studied. They were obtained solution of BVN copolymers in a preferential solvent of the poly(2-vinylnaphthalene) and the structure of solid organized copolymers prepared by polymerization solvent was also investigated. It could be shown that BVN block copolymers, as a function of the copolymer composition, exhibit the same set of periodic structures as AB and ABA block copolymers polystyrene-polybutadiene. A detailed description of the lamellar and inversed hexagonal structures of BVN copolymers is given and in addition the respective influence of the concentration, the nature, and the polymerization of the solvent on their geometrical parameters could be shown.
    Notizen: Nous avons préparé par polymérisation anionique sous vide des copolymères biséquencés polybutadiène-poly(vinyl-2 naphtalène) (BVN) et nous discutons les conditions de polymérisation qui conduisent à des copolymères isomoléculaires. En utilisant la diffraction des rayons X aux petits angles et la microscopie électronique nous avons déterminé structure des mésophases obtenues par dissolution des copolymères BVN dans un vant préférentiel des séquences poly(vinyl-2 naphtalène) et des copolymères organisés des préparés par polymérisation du solvant de la mésophase. Nous avons montré que les copolymères BVN présentent en fonction de la composition du copolymère les mêmes types de structure que les copolymères bi- et triséquencés polystyrène-polybutadiène. Nous décrirons en détail les structures lamellaire et hexagonale inversée des polymères BVN et l'influence de la concentration, de la nature et de la polymérisation solvant sur leurs paramètres géométriques.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/macp.1976.021771011
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  • 8
    Digitale Medien
    Digitale Medien
    Synthèse par voie radicalaire de polymères à extrémités hydroxylées, 5Parties 1 à 4: cf.1-4.. Polymérisation du méthacrylate de méthyle sous rayonnement ultravioletEn hommage au Professeur Kämmerer à l'occasion de son 65ème anniversaire (1976)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 177 (1976), S. 3139-3157 
    Details
    ISSN: 0025-116X
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Beschreibung / Inhaltsverzeichnis: Hydrogen peroxide is cleaved by UV irradiation (253,7 nm) into two hydroxyl radicals which can be used as initiators of polymerization, in order to give hydroxytelechelic polymers. Yields and number average molecular weights are influenced by the presence of an alcohol in the reaction medium, and the results depend on the solubility of the polymer in the alcohol used. The polymerisation of methyl methacrylate in methanol, being a non-solvent for the polymer, is described in the present paper. The characteristics of the polymers obtained are studied: distribution of molecular weights, microstructures, proportion of hydroxyl groups per macromolecule; the influence of several parameters - reaction time, proportion of hydrogen peroxide, and nature of the reaction medium - is also studied.
    Notizen: Sous l'action du rayonnement ultra-violet (253,7 nm), le peroxyde d'hydrogène est scindé en radicaux hydroxyle pouvant agir comme agents d'amorcage d'un processus de polymérisation. On peut ainsi obtenir des polymères hydroxytéléchéliques. L'adjonction d'un alcool au milieu réactionnel modifie les conditions de la polymérisation et permet de moduler les taux de conversion et les masses molécularies moyennes en nombre. Les résultats sont différents selon que le polymère est soluble ou non dans l'alcool. La polymérisation du méthacrylate de méthyle selon ce procédé, dans le méthanol non-solvant du polymère, fait l'object du présent travail. La nature des polymères obtenus est déterminée: mode de distribution des masses moléculaires, microstructure, taux de groupements hydroxyle par macromolécule; l'influence de divers paramètres est également étudiée: durée, proportions d'eau oxygénée, nature du milieu réactionnel.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/macp.1976.021771104
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  • 9
    Digitale Medien
    Digitale Medien
    Synthèse par voie radicalaire de polymères à extrémités hydroxylées, 9Partie 8: cf.11. Synthèse de polybutadiènes: étude des microstructures (1982)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 183 (1982), S. 303-317 
    Details
    ISSN: 0025-116X
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Notizen: Butadiene polymerization with hydrogen peroxide resulted in the simultaneous formation of oligomers, polymers, and high polymers. Analyses of their microstructures showed that oligomers have a higher content of 1,2-structures (28%) than the polymers (22%). The nature of the chain ends was determined with low molecular weight compounds. The content of 1,2-units is distinctly higher in the oligomers, which shows that initiation takes place preferably in 1,2- and propagation in 1,4-position. Besides hydroxyl end groups, other functional groups were detected in small quantities in the low molecular weight products: aldehydes, ketones, acids, hydroperoxides, and epoxides. These functions result from secondary reactions such as transfer, initiation, or termination reactions with alcohol releasing radicals.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/macp.1982.021830204
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  • 10
    Digitale Medien
    Digitale Medien
    Synthesis and characterization of vinyl monomers with blocked isocyanato groups (1987)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 188 (1987), S. 1367-1373 
    Details
    ISSN: 0025-116X
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Notizen: Vinyl monomers containing blocked isocyanato groups were prepared in one step, by blocking the isocyanato group of 2-isocyanatoethyl methacrylate with phenol, propanone oxime, butanone oxime, benzophenone oxime or ε-caprolactam, or in two steps, by blocking one of the two isocyanato groups of 4-methyl-1,3-phenylene diisocyanate with phenol or ε-caprolactam and the second group with 2-hydroxyethyl methacrylate. The 1H NMR and the IR spectra of these monomers are discussed.
    Zusätzliches Material: 3 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/macp.1987.021880612
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