Results 181 to 190 of about 19,854 (229)
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Journal of Polymer Science, 1955
AbstractA detailed study has been made of the intrinsic viscosity‐molecular weight relationship for a polybutadiene prepared at 50°C. and one prepared at 5°C. Original fractions were at least twice refractionated from very dilute solutions in an attempt to obtain fairly sharp distributions. Fox‐Flory K constants are observed to decrease with increasing
D. J. Pollock +2 more
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AbstractA detailed study has been made of the intrinsic viscosity‐molecular weight relationship for a polybutadiene prepared at 50°C. and one prepared at 5°C. Original fractions were at least twice refractionated from very dilute solutions in an attempt to obtain fairly sharp distributions. Fox‐Flory K constants are observed to decrease with increasing
D. J. Pollock +2 more
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Sequence distribution of 1,4‐polybutadienes
Die Makromolekulare Chemie, 1977AbstractThe spin‐decoupled 1H NMR and 13C NMR methods were presented for the determination of the cis‐trans sequence distribution in polybutadiene. Poly(butadiene‐2,3‐d2) and cis‐trans isomerized polybutadienes were used for the peak assignment and the resonance of methylene protons in cis‐trans linkage could be described as an A2B2 system.
Yasuyuki Tanaka +4 more
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Synthesis of Flower‐Like Polybutadiene
Macromolecular Chemistry and Physics, 2017Synthesis of complex macromolecular architectures exhibiting no chain ends such as flower‐like polymers is still of interest in the aim of investigating their physicochemical properties. For this purpose, poly(3,4‐dimethyl maleic imidoethyl acrylate)‐block‐polybutadiene‐block‐poly(3,4‐dimethyl maleic imidoethyl acrylate) triblock copolymer is ...
Nicol, Erwan +4 more
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Journal of Macromolecular Science: Part A - Chemistry, 1985
Abstract Polybutadiene (PB) can be easily halogenated by reaction with iodine chloride or bromine in tetrahydrofuran. The resulting glassy polymers were reacted with n-butyllithium, sec-butyl-lithium, and polystyryllithium in THF. Iodochlorinated PB gave a polybutadiene with a different cis/trans ratio with n-BuLi. The reformation of PB was accompanied
E. Ceauşescu +5 more
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Abstract Polybutadiene (PB) can be easily halogenated by reaction with iodine chloride or bromine in tetrahydrofuran. The resulting glassy polymers were reacted with n-butyllithium, sec-butyl-lithium, and polystyryllithium in THF. Iodochlorinated PB gave a polybutadiene with a different cis/trans ratio with n-BuLi. The reformation of PB was accompanied
E. Ceauşescu +5 more
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Solvent-polymer interactions in polybutadienes
Macromolecules, 1993Infinite-dilution activity coefficients of 26 solvents in three polybutadienes were determined by inverse gas chromatography in the temperature range 40-100°C. The polybutadienes have well-characterized structure and different molecular weights. The data are useful for the development of thermodynamic models for polymer-solvent interaction and for ...
ALESSI, PAOLO +3 more
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Macromolecules, 1993
The effect of peroxide cross-linking on the phase diagram and the scattering function for a critical mixture of perdeuterated polybutadiene (DPB) and protonated polybutadiene (HPB) has been examined by small-angle neutron scattering as a function of temperature. The scattering curves for the cross-linked blends were essentially temperature independent.
Hiroshi Jinnai +4 more
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The effect of peroxide cross-linking on the phase diagram and the scattering function for a critical mixture of perdeuterated polybutadiene (DPB) and protonated polybutadiene (HPB) has been examined by small-angle neutron scattering as a function of temperature. The scattering curves for the cross-linked blends were essentially temperature independent.
Hiroshi Jinnai +4 more
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Rheological Properties of Multichain Polybutadienes
Rubber Chemistry and Technology, 1965Abstract The introduction of one or two long chain branches into a polybutadiene molecule to form trichain or tetrachain molecules, respectively, leads to profound changes in Theological behavior. At low molecular weights the Newtonian (zero shear) viscosity is decreased relative to a linear polymer of the same molecular weight.
Gerard Kraus, J. T. Gruver
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Kurzkettige, lineare polybutadiene
Die Angewandte Makromolekulare Chemie, 1971AbstractMit ZIEGLER‐NATTA‐Katalysatoren aus Alkylaluminiumchloriden in Kombnination mit Kobalt‐ und/oder Nickelverbindungen können in einem nahtlosen Übergang 1,4‐cis‐Polybutadiene mit Molekulargewichten von 500 000 und mehr bis zusolchen mit Molekulargewichtenn von etwa 500 hergestellt werden.
Von Bernhard Schleimer, Heinrich Weber
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2009
Abstract Major Applications With one chiral center, 1,2-polybutadiene can exist in the amorphous atactic form and two crystalline forms: isotactic and syndiotactic. In the formation of 1,2-polybutadiene, it is believed that the syn p-allyl form yields the syndiotactic structure, while the anti p-allyl form yields the isotactic structures.
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Abstract Major Applications With one chiral center, 1,2-polybutadiene can exist in the amorphous atactic form and two crystalline forms: isotactic and syndiotactic. In the formation of 1,2-polybutadiene, it is believed that the syn p-allyl form yields the syndiotactic structure, while the anti p-allyl form yields the isotactic structures.
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Cis‐trans isomerization in polybutadiene
Journal of Polymer Science, 1957Abstract About twenty years ago, in an effort to transform natural rubber into gutta-percha, Meyer and Ferri irradiated a solution of Hevea in cyclohexane with ultraviolet light, but were unable to detect any cis-trans isomerization in polyisoprene.
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