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The crystallization behavior of poly(£-caprolactone) (PCL) in the miscible blends of PCL/ poly(vinyl chloride), PCL/poly(hydroxy ether of bisphenol A) and PCL/poly(bisphenol A carbonate) has been investigated by differential scanning calorimetry and polarized light microscopy. Through comparison of the PCL crystallization rate and calculation of the interaction energy density B between the miscible components in these blends, it was found that the effect of the noncrystallizable component on the crystallizability of PCL is not consistent with the strength of the specific interaction in the blends detected by FTIR but coincides with the interaction energy density B. The variation of PCL crystallizability reflects an effect of the apparent total intermolecular interaction in the blends. The influences of glass transition temperature, self-associated interaction of the noncrystallizable component and geometrical factors on the PCL crystallization rate and the intermolecular interaction in the blends are also discussed.

In this work, an impact copolymer polypropylene (ICPP) was separated into 4 fractions, A, B, C, and D. The phase structure, thermal behavior, and crystalline morphology of the ICPP and its 4 fractions were studied thoroughly using scanning electron microscopy (SEM). Dynamic mechanical analysis (DMA), differential scanning calorimetry (DSC), and polarized light microscopy (PLM). Results of SEM and DMA show that ethylene–propylene rubber (EPR) and part of the ethylene–propylene segmented copolymer disperse as toughening particles in the ICPP. The size and size distribution of these particles are determined by chain structure of the fractions of ICPP. From fraction A to fraction D, the morphology changes from noncrystalline to semicrystalline gradually, as shown by DSC. DSC results also indicate that thermal behavior of the ICPP agrees greatly with its chain structure. PLM demonstrates that it is difficult for the ICPP to grow perfect spherulites, that is, partially, because the matrix of ICPP, fraction D, has defects in its macromolecular chain. Another cause is that there is a good compatible structure in the ICPP and so the noncrystalline component (including all fractions) hinders the growth of the spherulite. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 103–113, 1999

In this work, impact copolymer polypropylene (ICPP) was fractionated into 4 fractions. ICPP and the 4 fractions were studied using Fourier transform infrared and 13C nuclear magnetic resonance analysis. The results demonstrate that fraction A is ethylene–propylene rubber, fraction B is ethylene–propylene (EP) segmented copolymer, fraction C is ethylene–propylene block copolymer, and fraction D is polypropylene with a few ethylene monomers in the chain. The differences in properties between different impact copolymer polypropylenes should be due to their fractions' differences in composition and chain sequence structure. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 93–101, 1999