MORPHOLOGY AND PHASE-BEHAVIOR OF BLENDS OF SYNDIOTACTIC AND ISOTACTICPOLYPROPYLENE .2. DIFFERENTIAL SCANNING CALORIMETRY, LIGHT TRANSMISSION MEASUREMENTS, AND PVT MEASUREMENTS

Blends of isotactic and syndiotactic polypropylene were studied by dif ferential scanning calorimetry (d.s.c.), light transmission measuremen ts and pressure-volume-temperature (PVT) measurements. D.s.c. measurem ents show the absence of any kind of melting point depression in the b lends. Furthermore, the change of the ratio of crystallized i-PP and c rystallized s-PP in the blends as a function of crystallization temper ature is discussed. PVT and light transmission measurements reveal tha t the rate of crystallization depends stronger on the crystallization temperature for i-PP than for s-PP. Thus at higher degrees of supercoo ling the crystallization of i-PP is faster and at lower supercoolings s-PP is able to crystallize faster. Copyright (C) 1996 Elsevier Scienc e Ltd.