title: Phase behavior in blends of ethylene oxide-propylene oxide copolymer and poly(ether sulfone) studied by modulated-temperature DSC and NMR relaxometry.
abstract: The state diagram of a blend consisting of a copolymer containing ethylene oxide and propylene oxide, P(EO-ran-PO), and poly(ether sulfone), PES, is constructed by using modulated-temperature differential scanning calorimetry (MTDSC), T(2) NMR relaxometry, and light scattering. The apparent heat capacity signal in MTDSC is used for the characterization of polymer miscibility and morphology development. T(2) NMR relaxometry is used to detect the onset of phase separation, which is in good agreement with the onset of phase separation in the apparent heat capacity from MTDSC and the cloud-point temperature as determined from light scattering. The coexistence curve can be constructed from T(2) values at various temperatures by using a few blends with well-chosen compositions. These T(2) values also allow the detection of the boundary between the demixing zones with and without interference of partial vitrification and are in good agreement with stepwise quasi-isothermal MTDSC heat capacity measurements. Important interphases are detected in the heterogeneous P(EO-ran-PO)/PES blends.
authors.affiliation: Department of Materials and Chemistry, Research Unit Physical Chemistry and Polymer Science (MACH/FYSC), Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium.
authors.forename: Luk
authors.initials: L
authors.lastname: Van Lokeren
authors.forename: Nicolaas-Alexander
authors.initials: NA
authors.lastname: Gotzen
authors.forename: Ronny
authors.initials: R
authors.lastname: Pieters
authors.forename: Guy
authors.initials: G
authors.lastname: Van Assche
authors.forename: Monique
authors.initials: M
authors.lastname: Biesemans
authors.forename: Rudolph
authors.initials: R
authors.lastname: Willem
authors.forename: Bruno
authors.initials: B
authors.lastname: Van Mele