Neutron and X-ray Scattering Studies on Semicrystalline Polymer Blends

Mixtures of poly(ethylene oxide), PEO, with protonated or deuteriated poly(methyl methacrylate), PMMAH or PMMAD, respectively, crystallized at 50 °C have been investigated by small-angle X-ray scattering, SAXS, and small-angle neutron scattering, SANS. It is shown that PMMA is incorporated into the amorphous phase between the crystalline lamellae. In addition, the thickness of the crystalline lamellae remains constant as a function of temperature which is in keeping with a small interaction parameter between the PEO and PMMA. The diffuse-phase boundary between the crystalline and amorphous phase is ca. 15 A greater for the SAXS measurements than that measured by SANS. These results suggest the existence of a region on the crystal surface in which the crystalline order dissipates and from which the noncrystallizable PMMA is excluded. © 1988, American Chemical Society. All rights reserved.