MICROSTRUCTURE EVOLUTION OF ISOTACTIC POLYPROPYLENE DURING ANNEALING: EFFECT OF POLY(ETHYLENE OXIDE)

The microstructure evolution of isotactic polypropylene (iPP) during annealing is reported. A few amount of poly(ethylene oxide) (PEO) which exhibits much lower melt temperature compared with iPP was introduced into iPP in this work. The crystalline structure of iPP was detected using differential scanning calorimetry (DSC) and wide-angle X-ray diffraction (WAXD), and the relaxation of iPP was characterized using dynamic mechanical analysis (DMA). The variation of PEO morphology was investigated by scanning electron microscopy (SEM). The results show that the crystallization, including the primary crystallization and second crystallization during annealing, as well as the relaxation of iPP matrix is promoted with the presence of PEO.