Etude de polymères en étoile à l'aide d'un appareil de chromatographie sur gel perméable utilisant un détecteur viscosimétrique. Kurzmitteilung.

Rheological properties of anionic polystyrenes. 7. Viscoelastic properties of six-branched star polystyrenes and their concentrated solutions

“…Therefore, the ratio of the intrinsic viscosity for sixbranched star polymer to that for linear polymer of the same molecular weight, g,3 = Mb/Mi = 0.61, can be estimated from eq 2 and 3. This value coincides well with results reported by Roovers et al 22 and by Meunier et al 23 According to Zimm and Stockmayer,24 the ratio of the mean-square radius by gyration (S2) for a star-branched polymer having branches of the same length to that for the corresponding linear polymer is given by gs2= (S2>b/(S2>, = (3P-2)/P2 (4) which is identical with the gi parameter defined by Ham.26 For six-branched star polymers, gs equals 0.666. As a result, the relation between gB and g, is gs = g"2•5.…”

Studien zur Verzweigung von Kettenmolekülen. XXIV. Über die Lösungsmittelabhängigkeit der Kontraktionsfaktoren g und g′ des Polyethylens niederer Dichte

“…sich abcr auch, daR, mit :lusnahme eines \Vertes, gilt : go' > s' Eine entspreclicnde Relation ist in der Literatur z. B. fur 4-und Gfach eternverzweigtes Polystyren (1,Osiingsmittel Renzen, Toluen, l'hetalosungsnlittel Cyclohexan) [22][23][24] bescbrieben worden. hber auch das entgegengesetzte Verhalten, g' > g,,' , wird experimentell gefunden, z. R. fur Sfach sternverzweigte Polystyrenniodelle L2.53.…”

Rubber

“…Mathematical treatment of branching and relation to viscosity is given by Shultz (63). Model systems of starlike molecules of polystyrene were used to give MWD and branching index (64). Certain anomalous behavior in viscosity has been observed with an apparent shift in the low molecular weight range (65).…”