Small-angle X-ray scattering analysis of craze-fibril structures

Load-bearing craze fibrils are fundamental to the ability of many polymer materials to support applied tensile stress. Three models of the scattering from craze-fibril structures have been compared through a rigorous analysis procedure. The results indicate that a diffuse-boundary model provides a more accurate description of scattering from the fibril structure than the standard Porod-law technique. Previously reported methods for determining fibril diameters were found to be inappropriate for high-impact polystyrene (HIPS) materials, overestimating the fibril diameters by as much as 60%. Indirect transforms using regularization theory of the fibril scattering data provide confirmation of the fibril diameters obtained from a power-law diffuse-boundary model, which is developed specifically for the craze-fibril structure of interest.