TIT# Nanostructure evolution of SIS thermoplastic elastomers during heating as
     revealed by USAXS and multi-dimensional chord distribution analysis
AUT# Stribeck, Norbert; Buzdugan, Emil; Ghioca, Paul; Serban, Sever; Gehrke, Rainer;
SOU# Macromol. Chem. Phys. (2002), 203(4), 636-644
LOC# xv069
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ABS# A new method for the analysis of small-angle X-ray scattering (SAXS) of
     anisotropic samples is introduced in the field of thermoplastic elastomers.
     It results in a detailed picture of the complex two-phase nanostructure
     and its range of order as a function of strain. A linear triblock
     copolymer from poly(styrene) and poly(isoprene) (SIS) and a brominated
     sample are studied as a function of elongation by ultra small-angle
     X-ray scattering (USAXS) from synchrotron. Styrene content is 30%.
     Two-dimensional scattering patterns are transformed to the Laplacian of
     the two-dimensional correlation function. Analysis of this chord
     distribution function (CDF) is demonstrated and compared to direct
     analysis of the fiber patterns. CDF analysis proves to be superior
     especially what the description of lateral arrangement of domains is
     concerned. Neat isotropic SIS reveals remarkable long-range order. When
     strained to high elongation, it exhibits elongated cylindrical domains
     arranged in a macro lattice, whereas the brominated material shows
     almost spherical domains arranged in microfibrils with some lateral order.
     Domain shape and arrangement is determined.