NEUTRON-SCATTERING FROM POLYMER BLENDS UNDER PRESSURE

A procedure is used to analyze small-angle neutron-scattering (SANS) d ata from a pressurized polymer blend mixture (deuterated polystyrene/p olyvinylmethylether). The Lattice-Fluid (LF) equation-of-state model i s used along with a compressible random phase approximation (RPA) in o rder to obtain free volume fractions and intermonomer interaction pote ntials. Solving the two sets of equations (LF and RPA) self-consistent ly within the fitting procedure to the SANS data provides an improveme nt over the familiar incompressible RPA model. In this approach, the f ree volume fraction is the main varying pa rameter. Intermonomer inter action potentials were found to depend on pressure (weakly) and temper ature (linearly). (C) 1995 John Wiley & Sons, Inc.