Crystallization of poly(tetramethylene succinate) in blends with poly(ε-caprolactone) and poly(ethylene terephthalate)

The crystallization behavior of polymer blends of poly(tetramethylene succinate) (PTMS) with poly(epsilon-caprolactone) (PCL) or poly(ethylene terephthalate) (PET) was investigated with differential scanning calorimetry under isothermal and nonisothermal conditions. The blends were prepared by solution casting and precipitation, respectively. The constituent polymers were semicrystalline materials and crystallized nearly independently in the blends. The addition of the second component to PTMS showed that PCL did not significantly influence the crystallinity of the constituents in the blends under isothermal conditions, whereas the crystallization of PTMS was slightly suppressed by crystalline PET. Nonisothermal crystallization under constant cooling rates was examined in terms of a quasi-isothermal Avrami approach. In blends, the rates of crystallization were differently influenced by the second component. The rate of the constituent that crystallized at the higher temperature was barely influenced by the second component being in the molten state, whereas the rate of the second component, crystallizing when the first component was already crystalline, was altered differently under isothermal and nonisothermal conditions. (C) 2004 Wiley Periodicals, Inc.