Simulating and evaluating small-angle X-ray scattering of micro-voids in polypropylene during mechanical deformation

Abstract

Micro‐voids that evolve during mechanical deformation in polypropylene have been characterized by small‐angle X‐ray scattering. Such voids can be modelled as randomly distributed cylinders which are oriented along the stretching direction, showing a log‐normal size distribution. The model and simulation results are presented here. Advantages and disadvantages of the approach, the validity of the model, and important considerations for data evaluation are discussed. Data analysis of two‐dimensional scattering images has been performed using a fully automated MATLAB routine by direct model fitting to scattering images.

Central small‐angle diffuse scattering from fibers is made of two components

“…13 Recently, a diamond-shaped pattern was interpreted as arising from an array of cylinders of finite length, and the dimensions of these cylinders was obtained by numerically fitting the pattern. 14 Here, fitting a wider range of full patterns and their changes during deformation and heating shows that a good fit and a consistent description requires two scattering components.…”

Cavitation‐Induced Stress Whitening in Semi‐Crystalline Polymers

“…The radius and thickness of cavities modeled as cylinder‐shaped objects can be individually calculated by direct model fitting of USAXS patterns . According to the computing results provided by Jiang et al., the radius and thickness for cavities produced in PCL isothermally crystallized at 35 and 40 °C were 3.5 and 141.5 nm, and 27.8 and 56.6 nm at strains ≈ 0.05 (the very beginning of cavity formation), respectively.…”

“…In Chen et al. 's work, a modified model based on the model established by Fischer was used. This modified model considered the orientational distribution of cavities with normal mainly along the stretching direction at the beginning.…”

Theory, practice and prospects of X-ray and neutron scattering for lignocellulosic biomass characterization: towards understanding biomass pretreatment

“…88 Recently, in a study of micro-voids evolution in polypropylene during mechanical deformation, the voids were modelled as cylinders of finite length. 140 Diamond-shaped SAXS patterns were fit with the form factor of a cylinder with a log-normal size 70 distribution of radius and length. 140 Scattering from both cellulose microfibrils and pores are often encountered in lignocellulosic biomass samples.…”