Extended x-ray absorption fine-structure studies of the internal aggregate structure in lightly sulfonated polystyrene. 2. Effect of uniaxial orientation

Abstract

EXAFS spectra were measured for three uniaxally extended lightly sulfonated polystyrenes, each containing 6.1 mol % sulfonate groups. The X-rays were linearly polarized, which enabled changes in local structure to be monitored parallel and perpendicular to the stretch direction. For the zinc-neutralized material, the metal-oxygen first-shell distance increased parallel to the stretch direction. Also, the Zn-O first-shell bond vectors were aligned in the stretch direction. A simple theoretical description was developed which allowed quantification of the second moment of the orientation function for these bond vectors. In the nickel-neutralized material, the metal-oxygen first-shell distance did not increase, but Ni-O bond vectors also aligned in the stretch direction