Internal nanostructure and structure-processing relationship of injection molded poly (butylene adipate-co-terephthalate) studied by SAXS-CT

Exploring the micro structure is of great benefit to the manufacture and application of polymers. Small angle X-ray scattering computed tomography (SAXS-CT), a novel method with ability of nondestructive spatial-resolved, is used to characterize injection molded Poly (butylene adipate-co-terephthalate) (PBAT). The three-dimensional distribution of long period, lamella thickness, amorphous layer thickness and orientation in PBAT made by in-jection molding have been successfully extracted using the reconstructed voxel scattering. According to the uncovered structure, the bulk PBAT can be clearly divided into three parts as skin, interlayer and core. The lamella thickness shares a distribution in U shape while long period, amorphous layer thickness and orientation share a Swing shape. More interestingly, a vortex ring inside the PBAT caused by the secondary flow during packing stage in injection molding can be observed via the reconstructed orientation distribution. Here, the internal microstructure and morphology revealed by SAXS-CT can shed a light on the relationship between processing and structure of PBAT.

Automated summary

SAXS-CT technique successfully reveals the internal microstructure and morphology of PBAT, showing the three-dimensional distribution of the material and the characteristics of different parts. Additionally, it can also observe a vortex ring inside the PBAT caused by secondary flow during injection molding process.