6533b86dfe1ef96bd12ca825
RESEARCH PRODUCT
Structure relaxation after temperature jumps in homogeneous polystyrene/poly(styrene-co-bromostyrene) blends
Gert StroblG. UrbanG. Urbansubject
Thermal equilibriumMaterials sciencePolymers and PlasticsScatteringThermodynamicsStyrenechemistry.chemical_compoundColloid and Surface ChemistrychemistryTemperature jumpPolymer chemistryMaterials ChemistryRadius of gyrationRelaxation (physics)PolystyrenePhysical and Theoretical ChemistryStructure factordescription
Concentration fluctuations in polymer blends and their change after a temperature jump were studied by time-dependent small angle X-ray scattering experiments. Measurements were conducted on homogeneous mixtures of polystyrene and a partially brominated derivative. Structure factors in thermal equilibrium show the form given by the random phase approximation, thus enabling a direct determination of theχ-parameter and the mean radius of gyration. TheT-dependence ofχ can be understood as the result of superposed enthalpic contributions and a free volume term. In theT-jump experiments, samples were quenched to temperatures near Tg. Relaxation occurs on the time scale of minutes and is nonexponential, becoming slower with time. Initial relaxation rates increase with increasing scattering vectorsq in accordance with theoretical predictions.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 1988-05-01 | Colloid & Polymer Science |