Flory-Huggins interaction parameters were determined as a function of composition for solutions of linear and of branched polyisoprene in cyclohexane (CH) at 25, 45, and 65 8C by means of vapor pressure measurements (moderate to concentrated solutions) and by vapor pressure osmometry (dilute solutions). The results demonstrate that CH is a considerably worse solvent for branched polyisoprene than for the linear analog at all temperatures and at all compositions. This observation corroborates the expectation based on a recent phenomenological approach, which accounts explicitly for the incapability of the segments of an individual polymer molecule to spread out over the entire volume of the system and for its ability to adjust its chain conformation to an altering molecular environment.
- Flory-Huggins interaction parameters
- Molecular architecture
- Vapor pressure