Institute of High Pressure Physics

In the NL-1 Laboratory of Plastic Deformation under High Pressure, we plastically deform polymer materials. We demonstrated a significant increase in mechanical properties of polyamide 6 (PA6) after hydrostatic extrusion.

In our recently published paper we explain the phenomena and propose strengthening mechanisms occurring in polymeric materials during high pressure plastic deformation. Read more in „Structural Hierarchy of PA6 Macromolecules after Hydrostatic Extrusion” Materials 16, 3435 (2023).

Figure. Schematic of changes in the fracture structure of PA6 samples before and after the hydrostatic extrusion (HE process). After the HE process, the spherulites have the shape of bars arranged in a regular manner parallel to each other.

Semicrystalline polymers consists of an amorphous phase and a crystalline phase. The higher the content of the crystalline phase, the stronger the polymer is. PA6 have crystalline regions, called crystallites - which can arrange themselves in an orderly fashion to form spherical spherulites, these spherulites are inside an amorphous matrix. During the Hydrostatic extrusion process, the spherulite structures in the polymer are deformed and sorted along the extrusion direction, leading to an increase in the strength properties of PA6.