SMALL-ANGLE SCATTERING INVESTIGATIONS OF POLY(EPSILON-CAPROLACTONE) POLYCARBONATE BLENDS .1. SMALL-ANGLE NEUTRON AND X-RAY-SCATTERING STUDYOF CRYSTALLINE BLEND MORPHOLOGY

Crystalline morphologies of poly(epsilon-caprolactone) (PCL) and deute rated polycarbonate (d-PC) blends were studied by small-angle neutron and X-ray scattering (SANS and SAXS). Measurements were conducted at b oth room temperature and temperatures above the melting point (60-degr ees-C) of PCL. Due to the different contrast between the phases for ne utrons and X-rays, SANS exhibited a monotonic drop in intensity with i ncreasing scattering angle while SAXS showed lamellar (peak) scatterin g. A two-correlation length model provided an excellent fit for the SA NS data over the entire composition range. This model reproduced not o nly the shape but also the absolute magnitude of the scattering curves . The long range correlation length (approximately 10(2) angstrom) and the short range correlation length (approximately 10 angstrom) derive d from this model are inferred to be associated with the crystalline P C domain and the local cluster in the amorphous phase (possibly result ing from crystallization-induced phase separation), respectively. Both the long range correlation length obtained from SANS and the long per iod measured from SAXS showed identical composition dependence. This f urther supports the applicability of the two-correlation length model and our interpretation.