TIT# The Equatorial Small-Angle Scattering During the Straining of
Poly(ether ester) and its Analysis
AUT# Stribeck, N.
SOU# J. Polym. Sci., Part B: Polym. Phys. (1999), 37, 975-981
LOC# xv033 @selbst.ftx
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ABS# A method for the quantitative analysis of two-dimensional (2D)
small-angle X-ray scattering (SAXS) patterns with fiber symmetry
by successive information filtering is proposed and applied to a series
of images recorded durig a straining experiment of a two-phase polymer
sample at a synchrotron beamline. The studied equatorial scattering is
similar to the frequently discussed void scattering, but originates from
an ensemble of rodlike soft domains (needles) in the sample, orientated
in the direction of strain. The intensity is extracted and projected onto
the equatorial plane, the ideal two-phase structure is extracted, and the
2D chord distribution is computed. This curve describes a 2D two-phase
morphology made from needle cross-sections embedded in matrix material.
Because interparticular correlation is found to be weak in the chord
distribution, pure particle scattering is assumed. Modeling the needle
cross-sections by circular disks leads to a simple theory, which allows
the deconvolution of a disk diameter distribution from the chord
distribution. It is shown hwo parameters of the disk diameter distribution
can be computed without deconvolution. For the selected poly(ether ester)
thermoplastic elastomer the study of the soft domain needles indicates
strain-induced hardening. While for low elongation $\epsilon$ the soft
needles are more compressible than the microfibrillar matrix, saturation
is observed for $\epsilon > 2.5$.