TIT# Deformation Behavior of a Poly(ether ester) Copolymer. Quantitative
     Analysis of SAXS Fiber Patterns
AUT# Stribeck, Norbert; Fakirov, Stoyko; Sapoundjieva, Diana
SOU# Macromolecules (1999), 32, 3368-3378
LOC# xv036 @selbst.ftx
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ABS# A method for the quantitatively analysis of two-dimensional small-
     angle X-ray scattering (SAXS)
     patterns with fiber symmetry is proposed and applied to a series of images
     recorded during straining and relaxation cycles of a two-phase block
     thermoplastic elastomer sample at a synchrotron beamline.  The studied
     longitudinal scattering originates from microfibrils or lamellar stacks
     built from alternating soft and hard domains.  The scattering intensity of
     the patterns is projected onto the direction of strain, yielding
     one-dimensional scattering curves.  From these curves, interface
     distribution functions are computed and analyzed using an advanced
     stacking model with a small set of parameters.  Not only the average domain
     heights but also four parameters characterizing each of two height
     distributions (hard and soft domains) are determined as a function of
     elongation.  These parameters are norm, mean, variance, and skewness.
     They describe the response of the filled elastic network to strain.  For
     the studied poly(ester ether) thermoplastic elastomer, the quantitatively analysis
     shows that two microfibrillar components (an intact and a damaged one) can
     be identified in the patterns from samples at medium elongation as well as
     in patterns recorded during relaxation from medium elongation.  Although
     the scattering patterns differ considerably, the hard domain distributions
     extracted from the fits are identical.  The difference between elongated and
     relaxed state is in the distribution of the soft domain heights.  There
     are indications for a nonuniform elasticity of the soft domains.  The average
     internal strain of the soft domains can be computed and compared to the
     external strain; and pull out of tie molecules taut among different
     microfibrils can be studied.