PDMS Samples Research Articles

An investigation of the interaction of potassium ions with poly(dimethylsiloxane)

The interactions of potassium ions with α, ω-hydroxy-terminated and α, ω-trimethylsilyl-terminated poly(dimethylsiloxanes) (PDMS) have been investigated. After mixing with potassium hydroxide followed by partial extraction, the α, ω-hydroxy-terminated PDMS samples gave elastomeric materials which are thought to result from aggregation of terminal potassium silanolate ion pairs. Uniaxial tensile testing of these materials was carried out at 298 K. The α, ω-trimethylsilyl-terminated PDMS, when mixed with potassium hydroxide, however, gave completely soluble material following identical solvent extraction procedures.

Studies of cyclic and linear poly(dimethylsiloxanes): 28. Viscosities and densities of ring and chain poly(dimethylsiloxane) blends

Two physical properties, density and low-shear viscosity, were studied in order to investigate the effects of blending chemically identical but topologically different poly(dimethylsiloxane) (PDMS) fractions (i.e. rings and chains). Deviations from a purely additive model were obtained for 50:50 (by volume) blends of cyclic and linear PDMS samples. Such investigations may be able to probe packing capabilities, the amount of free volume in a fraction and the extent and effects of chain threading.

Comportement au voisinage des conditions «théta» des solutions semidiluées et concentrées de poly(diméthylsiloxane) dans le styrène

AbstractThe thermodynamical properties of poly(dimethylsiloxane) (PDMS) were studied in the theta‐solvent styrene. Moderately diluted and semidiluted solutions of three PDMS samples with weight‐average molecular weights M̄w = 23 500, 160 000, and 860 000 were investigated by means of light scattering near the theta‐temperature. The dependency of the interaction parameter X on temperature and concentration was established for the three samples. The study of the third virial coefficient A3 showed that A3 is independent of molecular weight and temperature as predicted by theory. However, the experimental value of A3/(AM) was higher than expected. The critical properties, i.e., critical point and spinodal, were considered.