Results 171 to 180 of about 12,723 (223)
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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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Macromolecules, 2003
Atomistic simulations of two isomers of polybutadiene (PB), cis-1,4-PB and 1,2-PB, have been conducted using the end-bridging Monte Carlo algorithm.
P. Gestoso +3 more
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Atomistic simulations of two isomers of polybutadiene (PB), cis-1,4-PB and 1,2-PB, have been conducted using the end-bridging Monte Carlo algorithm.
P. Gestoso +3 more
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Near‐IR spectrum of polybutadiene
Journal of Polymer Science Part A: Polymer Chemistry, 1996Abstract : The vibrational overtone spectrum of polybutadiene was recorded up to 14,000/cm and interpreted in the local mode model. The methylenic and olefinic CH stretch progressions, with anharmonicities of 66 and 59/cm, respectively, were identified for delta v = 2, 3,4 and 5.
D. L. Snavely, C. Angevine
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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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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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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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INFRARED SPECTRA OF POLYBUTADIENES. NOTE I: SYNDIOTACTIC-1,2 POLYBUTADIENE
1967ABSTRACT The infrared spectrum of syndiotactic-1,2 polybutadiene was studied on polymer prepared by polymerization of butadiene with the aid of a catalyst based on triethyl aluminum and vanadium triacetylacetonate, and subsequent cold extraction with benzene.
D. MORERO, E. MANTICA, L. PORRI
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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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