Solvent‐cast films of blends of poly(ϵ‐caprolactone) (PCL) with poly(vinyl chloride) (PVC) were examined by low‐angle x‐ray scattering and by small‐angle light scattering. X‐ray scattering from crystalline compositions were analyzed using the Tsvankin–Buchanan technique and led to values of the repeat period of the lamellar structure and the thickness of the crystalline and amorphous layers. With increasing content of PVC, the amorphous layer thickness increased sufficiently to accommodate the PVC, leading to values of the linear crystallinity consistent with macroscopic measurements by density and DSC techniques up to about 50% PVC by weight. Above this concentration, the lamellar structure no longer appeared to be volume filling. At high concentration of PCL, the polymer consisted of volume‐filling spherulites containing the lamellar substructure. Spherulite sizes were measured by light scattering and absolute light scattering intensities were consistent with calculations based upon the degree of crystallinity and anisotropy of the spherulites. Compositions containing more than 60% PVC were amorphous. Low‐angle x‐ray scattering was interpreted in terms of the Debye–Bueche theory which leads to values for a correlation distance lc and the mean‐square electron density fluctuation 〈η2〉 (which was also obtained from the invariant). By the method of Porod, the correlation distances were resolved into persistence lengths within the two phases, which were determined as a function of composition. The fluctuation 〈η2〉 was analyzed in terms of a two‐phase model to show that its value was somewhat larger than would be obtained if the phases were composed of the pure components. It was not possible to uniquely determine their compositions. The data were consistent with the existence of a transition zone of the order of 30 Å thick between phases.

Blends may be made of pairs of polymers where neither, one, or both components are crystalline. The state of compatibility for such blends may be deduced by x‐ray and light scattering. A survey of recent studies in this laboratory of several binary blends of crystalline and amorphous polymers is presented.

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A B S T R A C T An orange juice based model system was set up wherein variables

The small angle x-ray scattering from blends of isotactic and atactic-~•~tyrP.ne has been studied. Results have been interpreted and ~ompared using the Tsvankin, Vonk and Hosemann techniques. The studies suggest that segregation of the atactic component occurs during crystallization within the growing spherulite of the isotactic component. However, since the interlamellar distance does not increase with atactic content, segregation is believed to occur with the formation of domains larger than iu-t~rlamellar but smaller than spherulite size.