Search results for "Diluent"
showing 3 items of 13 documents
Tracer diffusion in polymer and organic liquids close to the glass transition studied by forced rayleigh scattering
2007
Translational diffusion coefficients D of photochronic dye molecules have been measured by forced Rayleigh scattering in polymer diluent systems at compositions from pure polymer to pure diluent. D could be measured down to below the glass transition temperature T g. In the pure diluent, D(T g) was found typically about two decades below that in the pure polymer but still far above the Stokes-Einstein prediction extrapolated from high temperatures. Some experimental results are in contrast with predictions from free-volume theory.
Diffusion of spherical micronetworks in polymer diluent systems and melts studied by dynamic light scattering techniques
1994
Spherical polystyrene (PS) micronetworks can be prepared in microemulsion with bulk radii of 5–60 nm and different cross-linking densities. The diffusion of these PS spheres has been studied in polymer diluent systems ranging from dilute solutions to plasticized melts by using forced Rayleigh scattering and photon correlation spectroscopy. On increasing the PS concentration, a colloid glass transition is observed at a volume fraction ΦC ≈ 0.64 of the swollen spheres. At higher concentration inside the “colloid glass” state the sphere diffusion is slowed down and becomes very complex but can be observed up to the limit of a melt of collapsed spheres.
Mechanical behavior and structure of single beads of homogeneous and macroporous styrene–divinylbenzene copolymers
1982
The stress–stain and ultimate behavior in compression of homogeneous and macroporous beads of styrene–divinylbenzene copolymers has been investigated in the dry state or in equilibrium with toluene, acetone, methanol, and water. The penetration modulus A indicates sensitively the transition from the glassy into the rubbery state induced by an increase in temperature or swelling. For macroporous copolymers, A of the glassy polymers is mainly determined by the porosity P, while in the rubbery region it primarily depends on the matrix structure (degree of crosslinking and concentration and composition of the diluent). The high value of the slope s of the A vs. P dependence (s ∼ −3) for macropo…