PRESSURE-DEPENDENCE OF THE FLORY-HUGGINS INTERACTION PARAMETER IN BINARY POLYMER BLENDS INVESTIGATED BY SANS

The pressure dependence of the Flory - Huggins interaction parameter o f two binary polymer blends was investigated by small angle neutron sc attering (SANS). We studied the polymer blends deutero - Polystyrene / Polyvinylmethylether (d - PS / PVME) and deutero - Polystyrene / Poly phenylmethylsiloxane (d - PS / PPMS), exhibiting decomposition at high and at low temperatures, respectively. In both cases the enthalpic co ntribution of the Flory - Huggins parameter is not affected by pressur e in the investigated pressure range between 1 and 1200bars, whereas t he absolute value of the entropic contribution is generally a decreasi ng function of pressure.