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Titolo:
Influence of architecture on arm dimensions and interaction parameters in polybutadiene star polymers
Autore:
Hutchings, LR; Richards, RW;
Indirizzi:
Univ Durham, Interdisciplinary Res Ctr Polymer Sci, Durham DH1 3LE, England Univ Durham Durham England DH1 3LE Polymer Sci, Durham DH1 3LE, England
Titolo Testata:
MACROMOLECULES
fascicolo: 3, volume: 32, anno: 1999,
pagine: 880 - 891
SICI:
0024-9297(19990209)32:3<880:IOAOAD>2.0.ZU;2-V
Fonte:
ISI
Lingua:
ENG
Soggetto:
ANGLE NEUTRON-SCATTERING; THERMODYNAMIC INTERACTIONS; BLOCK COPOLYMERS; PHASE-TRANSITIONS; BRANCHED POLYMERS; MIXING BEHAVIOR; DILUTE-SOLUTION; LIQUID-STATE; BLENDS; FORCES;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
52
Recensione:
Indirizzi per estratti:
Indirizzo: Richards, RW Univ Durham, Interdisciplinary Res Ctr Polymer Sci, Durham DH1 3LE, England Univ Durham Durham England DH1 3LE Durham DH1 3LE, England
Citazione:
L.R. Hutchings e R.W. Richards, "Influence of architecture on arm dimensions and interaction parameters in polybutadiene star polymers", MACROMOLEC, 32(3), 1999, pp. 880-891

Abstract

Star branched polymers of polybutadiene with 3, 4, 8, and 12 arms have been synthesized with one arm perdeuterated. Small-angle neutron scattering data have been collected for each of the star polymers and for the four-arm star polymer mixed with hydrogenous linear polybutadiene of the same molecular weight either as a single arm or of the whole star. The labeled four-armstar polymer has also been mixed with the equivalent hydrogenous star polybutadiene. For the pure labeled star polymer the scattering is dominated bya peak located at a scattering vector determined by the radius of gyrationof the arm. As the labeled star polymer is diluted by adding hydrogenous polymer, the peak declines in amplitude and the maximum scattered intensity shifts to zero scattering vector. The scattered intensity for each sample has been fitted with expressions based on random phase approximation theory and the radius of gyration of the labeled arm was obtained. Two interactionparameters were needed to obtain acceptable fits of the theoretical expressions to the data. Indisputable evidence for increased stretching of the labeled arm as the number of arms in the star polymer increases has been obtained, and the stretching factor has been compared to predictions of a liquid state theory of star polymers. The interaction parameters obtained are considered to be reflections of the differential screening of core and coronasegments of the star molecules, an integral aspect of the liquid state theory, rather than true Flory-Huggins-type interaction parameters.

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Documento generato il 27/10/20 alle ore 11:11:13