X-ray measurement of chain orientation in non-crystalline polymers

Structural origin of stress and shape recovery in shape memory starch

“…Such tendency has already been observed for sample deformed above the glass transition and was attributed to chain orientation [19e21]. This result suggests that amorphous chain backbone is oriented preferentially in the direction of deformation [19,21].…”

“…Whereas in the direction perpendicular to the axis of deformation (f ¼ 90 ), the intensity is higher for distances ranging from 0.4 to 0.5 nm, and the top of the halo is placed at 0.45 nm. The amorphous halo, which is reflecting the local order into the polymer, is correlated to the intra and inter molecular distances distribution [21,22]. Similar shift of the halo has already been reported for elastically deformed glassy PMMA [15], and was attributed to a change of intermolecular distances.…”

Application of cylindrical distribution functions to wide-angle X-ray scattering from oriented polymers

“…3(c) shows meridional and equatorial sections of the anisotropic scattering compared with the isotropic scattering. It can be seen that the second halo is the most distinctly anisotropic feature and we have previously used this halo to measure chain orientation in PMMA (Pick, Lovell & Windle, 1980). The anisotropic scattering decreases to zero by Sma x, as required for minimum termination ripple in the CDF.…”

“…The symmetrical transmission geometry together with the incident beam monochromator were the same as used by Pick, Lovell & Windle (1980). The data were collected at intervals of 1 o in 20 (Cu Ka radiation) and 9 o in a.…”

“…Since the derivation of D(a) from the data makes no allowance for any intrinsic azimuthal width due to disorder (Pick, Lovell & Windle, 1980), the patterns are to some extent over-sharpened. However, the broadening caused by use of only a few terms of the series should counteract this.…”