Preparation and properties of PP/PET filament blends for 3D printing applications

Abstract

In order to expand the application of polypropylene (PP) in 3D printing technology and improve its mechanical properties, PP/polyethylene terephthalate (PET) blend filaments were prepared by extruding PP with PET using melt blending. The rheological behavior, crystallization structure, melting and crystallization behavior, microstructure, mechanical properties of the filament blends and 3D printed samples with different mixing ratios of PP, PET were analyzed. The results show that the viscosity of PP/PET blends decreases with the increase of shear rate and exhibits shear thinning behavior. PET acts as a nucleating agent and does not change the crystal shape of PP during PP crystallization. The melting temperature of PP is about 150 ℃, and the crystallization temperature increases with the increase of PET concentrations. The PP matrix and PET dispersed phase have obvious "sea-island" structure, in which PET is the "island" phase, with a diameter of 2-5 μm. With the increase of PET concentrations, the tensile strength of filament blends is improved. Simultaneously, the tensile strength and the impact strength of the 3D printed samples is improved. However, the mechanical properties of 3D printed samples are generally lower than those of filament blends due to interlayer interaction.

Keywords

• polypropylene
• blending modification
• mechanical property
• 3d printing