MORPHOLOGY STUDIES OF THE LIQUID-INDUCED CRYSTALLIZATION OF POLY(ETHYLENE-TEREPHTHALATE) - EFFECTS OF POLYMER BLENDING, NUCLEATING-AGENTS, AND MOLECULAR-WEIGHT

The morphology associated with the liquid‐induced crystallization of poly(ethylene terephthalate) (PET) blended either with poly(tetramethylene terephthalate) (PTMT), atactic polystyrene (APS), or polycarbonate of bisphenol A (PC) was studied, along with the effects of nucleating agents and polymer molecular weight on this type of crystallization in PET. It was found that melt‐mixed blends of PET and either PTMT or PC led to an apparent well‐mixed, two‐component material in which some copolymer formation may be in evidence judging from the material superstructure. Blending PET with APS appeared to produce distinctly phase‐separated materials in which PET could be crystallized and APS dissolved out of the structure as a result of treatment of the blend with certain types of liquid. The incorporation of nucleating agents into PET was shown to measurably influence the spherulitic character of the subsequently liquid‐induced crystallized polymer. Finally, it was determined that liquid‐induced crystallized PET samples with number‐average molecular weights of 18,000 and 30,000 had identical characteristic morphology and apparent crystallization kinetics. Copyright © 1979 John Wiley & Sons, Inc.