Binary blends of a semicrystalline polymer, poly (butylene terephthalate),
PBT, with an amorphous polymer, polyarylate, PAr, were studied for a wide
range of compositions. SMall angle x-ray scattering, thermal and mechanical
analyses were conducted to determine the location of the uncrystallizable
PAr relative to the crystal lamellae of PBT, for blends crystallized by
heating from the quenched state. Comparison of experimental and calculated
long periods indicates that interlamellar PAr placement becomes less
probable as the PAr composition increases. When PBT crystallizes in these
blends, Most PAr is rejected from the regions near the crystal surfaces when
PAr fraction exceeds about 0.40.