Study of the Physical and Mechanical Properties and Quality of the FDM Printing of High-Pressure Polyethylene/Al2O3 Nanofiber Nanocomposites

The influence of modified Nafen fibers and the nozzle temperature of a 3D printer on the physical and mechanical properties and printability of high-pressure polyethylene (HPP)/Al2O3 nanofiber (Nafen) nanocomposite is studied. It is found that the modification of HPP with Nafen fibers, as well as an increase in the temperature of the nozzle of the 3D printer leads to a decrease in warping of the HPP printed on a “cold” workbench. A change in the structure of thin film samples obtained by fused deposition modeling (FDM) printing with a change in the extrusion temperature and the modification of HPP with Nafen nanofibers is proven. An increase in the nozzle temperature and modification of the polymer matrix leads to an increase in the relaxation time of the material structure, which under conditions of rapid cooling contributes to the implementation of a metastable state characterized by a lower density of the fluctuation network in the amorphous part of the HPP. The relationship between the change in the free volume determining the shrinkage of the material during the FDM process, and the change in the melt cooling viscosity and its relaxation time is shown.