Isothermal Crystallization Behavior of Isotactic Polypropylene H/D Blends as Viewed from Time-Resolved FTIR and Synchrotron SAXS/WAXD Measurements

Abstract

The melt isothermal crystallization behavior has been investigated for a series of blend samples of deuterated (D) and hydrogenated (H) species of isotactic polypropylene by means of time-resolved Fourier transform infrared (FTIR) spectral measurement and simultaneous small-angle X-ray scattering (SAXS)/wide-angle X-ray diffraction (WAXD) measurements using synchrotron radiation source in SPring-8. The SAXS data collected were analyzed in the three different time regions. The Guinier plot in the early stage of crystallization gave the average size of isolated domains formed in the melt. In the middle stage, the correlation between these domains was analyzed using the Debye−Bueche equation. In the later stage of crystallization, the correlation function was calculated to estimate the degree of crystallinity and the long period of the stacked lamellae. The IR data analysis clarified the formation process of regular helical chains in the isothermal crystallization phenomenon. The combination of FTIR, WAXD, a...