Star-Branched Polymers. 5. The ι Temperature Depression for 8- and 12-arm Polyisoprenes in Dioxane

B. J. Bauer, L. J. Fetters*, N. Hadjichristidis, J. E.L. Roovers

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

86 Scopus citations

Abstract

The θ temperature depression for a series of low molecular weight 8- and 12-arm polyisoprene stars has been measured in dioxane. Previously, Hadjichristidis and Roovers demonstrated that the low molecular weight 4- and 6-arm starshaped polyisoprenes did not show, in dioxane, depressed 6 temperatures. This was ascribed to the 1/3 - X2 term having a nearzero value in this solvent. However, our results show that the 1/3 - X2 term values are greater than zero for the 8- and 12-arm star cases and that these values increase as the degree of branching increases. Values for the term V3 - X2 have been calculated for two separate cases of g values, to wit, g theoretical and g (limiting) as Mw→À. The calculation of the V3 - X2 values was accomplished using a modification of the three-parameter theory of Candau, Rempp, and Benoit. The modification was necessary since the Candau, Rempp, and Benoit treatment was found to poorly approximate the experimentally observed decrease in 8 temperature of the 8- and 12-arm polyisoprenes.

Original languageEnglish (US)
Pages (from-to)2410-2413
Number of pages4
JournalJournal of the American Chemical Society
Volume102
Issue number7
DOIs
StatePublished - 1980
Externally publishedYes

ASJC Scopus subject areas

  • Catalysis
  • Chemistry(all)
  • Biochemistry
  • Colloid and Surface Chemistry

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