The equatorial small-angle scattering during the straining of poly(ether ester) and its analysis

Abstract

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 during 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 how 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 ϵ the soft needles are more compressible than the microfibrillar matrix, saturation is observed for ϵ > 2.5. © 1999 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 37: 975–981, 1999

Effect of processing parameters on the morphology development during extrusion of polyethylene tape: An in-line small-angle X-ray scattering (SAXS) study

“…It should be mentioned that some of the 2D SAXS patterns in Figure 3, also show evidence of scattering perpendicular to the elongation direction in the form of equatorial streaks. These are present at the same time as the meridional scattering and have been observed previously during melt spinning and shearing of polymers [36,39,49,52]. The occurrence of equatorial streaks is attributed to the formation of bundles of highly oriented molecular chains (or shish), which have a repeat distance perpendicular to the elongation direction.…”

Synchrotron studies of polymers at DND-CAT

“…The invariant drops continuously due to two processes that presumably take place simultaneously, the pull-out of hard segments from the hard domains and stress induced crystallization of the soft segments (McLean & Sauer, 1999;Stribeck 1999Stribeck & 1997. Both of these processes very likely occur simultaneously, although an interesting observation can be made from the results in Figure 3.…”

“…The electron density difference between the hard and soft segment domains gives rise to small angle scattering. This class of materials has been the subject of recent reports (McLean & Sauer, 1999;Stribeck, 1999;Stribeck 1997), which show that TPE's display complex behavior as a function of strain. The present report, on a real-time study of the deformation of a thermoplastic elastomer, shows data that complements the earlier work.…”

Scattering of Soft Condensed Matter: From Fundaments to Application

“…In a study of a poly(ether ester) material [48], the evolution of its transverse structure during straining in a stretch-hold [49] experiment has been evaluated. {I} 2 (s 12 ) is computed by means of a program which is much more simple than sf vp.pro listed on p. 43.…”