The objective of this study was to characterize the following materials: Selenis Safe FT 104 – PET 104, Selenis Safe TT 100 – PET 100 and glycol modified materials (PET-G). Besides the characterization, the objective was to make filaments that would be used for the fused filament fabrication. The filaments from these polymeric materials could not be made because during production they had low viscosity and were too stretched by gravity during extrusion. The obtained filaments had very small diameter that could not be used for the production of filaments used for 3D printing which was the primary objective of the study. The test materials were extruded again, this time with pre-drying according to the manufacturer's instructions. The obtained filaments were treated (processed) in granulator. The obtained materials were characterized with and without prior drying, and determined whether there was any difference in mechanical properties, stability and morphology. The mechanical and thermal properties of pure components, prepared composites and polymer blends were determined. Moreover, the morphology was examined, based on the mechanical properties of the selected samples. FTIR spectra were recorded and surface properties were analysed by measuring the contact angle of the tested materials. Based on the obtained results, the conclusion is that the mechanical properties of these materials are changing with proper drying of the samples. Using DSC analysis, it was found that samples subjected to different thermal processes achieved different degrees of crystallinity. FTIR spectroscopy obtained characteristic bands of the test materials. Examining of the morphology of pure materials and composites gave the results of mechanical testing. Conducted analysis of contact angle measurements revealed that untreated calcium carbonate and calcium carbonate treated with stearic acid did not significantly affect the surface properties of the composite hydrophobicity.