SOLUTION PROPERTIES OF LADDER-LIKE POLYMER POLYPHENYLSILSESQUIOXANES

Solution properties of ladder-like polymer polyphenylsilsesquioxane (PPS) were studied by measurement of intrinsic viscosity, small angle laser light scattering and gel permeation chromatography. It was found that PPS can be modeled with a wormlike continuous cylinder rather than a wormlike coil. A plot of (M~2/η])~(1/3) vs. M~(1/2) was employed in obtaining the persistence length (2λ)~(-1) and effective hydrodynamic diameter. When MW≤5×10~5, Mark-Houwink equation is adequate in describing the relationship between MW and η] with αabout unity. This implies that PPS chain is semi-stiff. For GPC experiments, it was shown that universal calibration can be applied in PPS. When molecular weights of PPS are sufficiently high, their molecular weight distributions are often very broad.

SOLUTION PROPERTIES OF LADDER-LIKE POLYMER POLYPHENYLSILSESQUIOXANES

 Solution properties of ladder-like polymer polyphenylsilsesquioxane (PPS) were studied by measurement of intrinsic viscosity, small angle laser light scattering and gel permeation chromatography. It was found that PPS can be modeled with a wormlike continuous cylinder rather than a wormlike coil. A plot of (M²/η])^1/3 vs. M^1/2 was employed in obtaining the persistence length (2λ)^-1 and effective hydrodynamic diameter. When MW≤5×10⁵, Mark-Houwink equation is adequate in describing the relationship between MW and η] with α about unity.This implies that PPS chain is semi-stiff.For GPC experiments,it was shown that univeral calibration can be applied in PPS.When molecular weights of PPS are sufficiently high,their molecular weight ditributions are often very broad.