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;/[η]）;vs. M;was employed in obtaining the persistence length （2λ）;and effective hydrodynamic diameter. When MW≤5×10;, 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.