Improvement of Polymer Segmentation by X-ray Phase Contrast Computed Tomography

This paper presents an experimental study comparing X-ray phase contrast imaging (XPCI) computed tomography with standard attenuation-based X-ray computed tomography for the characterization of four polymer materials (PMMA, POM, PTFE, PP). XPCI, which leverages the refraction of X-rays by a specimen, offers high robustness against beam hardening effects and high sensitivity for low density and low atomic number materials, such as polymers. The experiments, conducted on a CT system with an integrated Talbot-Lau grating interferometer for phase extraction, demonstrate that XPCI can provide contrast-to-noise ratios (CNRs) more than twice as high in the polymer materials compared to conventional attenuation contrast imaging. Specifically, the CNR between PMMA and POM could be significantly increased from 2.6 to 3.6, possibly allowing an easier segmentation. The findings presented in this work suggest that XPCI is a promising method for the characterization of polymer materials in recycling processes.