The article presents an overview of currently used polymer materials in various areas of medicine. Most often, polymeric materials are used in the production of medical equipment, cardiology, surgery, dentistry. They are mainly used, among others for the production of gloves, surgical sutures, various type of containers, specula or drip. Currently, by using additive manufacturing techniques, anatomical models of bone structures, surgical templates and implants are made of polymer materials. Thanks to their use, it is possible to significantly reduce the duration of the procedure and increase its precision. By using biodegradable polymers, it is possible to regenerate or replace damaged or diseased tissues or organs. Based on the analysis carried out, huge progress was noted in the use of polymeric materials in the field of medicine through the use of additive methods. However, there is a need for further synthesis of new and modification of existing polymers in the aspect of contact with the patient's body.

In the article research related to the increasing in the scope of application of additive technologies in the construction of machines for the production of gears with involute and sinusoidal profile from polymeric materials was presented. The designed original research stand and with its use carried out a series of preliminary fatigue tests of the obtained polymer gears with an involute and sinusoidal profile was show. The tested gears were obtained in the technology of rapid prototyping by the FFF (Fused Filament Fabrication) method from polymer composites obtained in the form of an ABS (acrylonitrile/butadiene/styrene) -based filament. Based on the results obtained, it was noticed that the temperature in the meshing zone of the gears with involute profiles is higher than for sinusoidal profiles, regardless of the type of composite from which the gears were made. It should also be noted that in the range of nominal load, the sound intensity level of the meshing zone is also lower for gears with a sinusoidal profile than for gears with an involute profile. Based on the tests carried out, an increase in sound intensity was noticed in the case of gears obtained from selected composites (Table 2) compared to the gear obtained from unfilled ABS. However, in the case of gears obtained from the tested composite materials, we observe a decrease in the gear operating temperature (Table 2). The most favorable results of these tests were obtained for gears with a sinusoidal profile obtained from ABS + P2 composite, which show the lowest operating temperature of the gear. It should also be mentioned that slightly worse results were obtained for involute gears.

As part of the present work, polymer composites used in 3D printing technology, especially in Melted and Extruded Manufacturing (MEM) technology, were obtained. The influence of modified fillers such as alumina modified silica, quaternary ammonium bentonite, lignin/silicon dioxide hybrid filler and unmodified multiwalled carbon nanotubes on the properties of polycarbonate (PC) composites was investigated. In the first part of the work, the polymer and its composites containing 0.5–3 wt.% filler were used to obtain a filament using the proprietary technological line. The moldings for testing functional properties were obtained with the use of 3D printing and injection molding techniques. In the next part of the work, the rheological properties—mass flow rate (MFR) and mechanical properties—Rockwell hardness, Charpy impact strength and static tensile strength with Young’s modulus were examined. The structure of the obtained composites was also described and determined using scanning electron microscopy (SEM). The porosity, roughness and dimensional stability of samples obtained by 3D printing were also determined. On the other hand, the physicochemical properties were presented on the basis of the research results using thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), wide angle X-ray scattering analysis (WAXS) and Fourier Transform infrared spectroscopy (FT-IR). Additionally, the electrical conductivity of the obtained composites was investigated. On the basis of the obtained results, it was found that both the amount and the type of filler significantly affected the functional properties of the composites tested in the study.

Polymer fiber composites are increasingly being used in many industries, including the defense industry. However, for protective applications, in addition to high specific strength and stiffness, polymer composites are also required to have a high energy absorption capacity. To improve the performance of fiber-reinforced composites, many researchers have modified them using multiple methods, such as the introduction of nanofillers into the polymer matrix, the modification of fibers with nanofillers, the impregnation of fabrics using a shear thickening fluid (STF) or a shear thickening gel (STG), or a combination of these techniques. In addition, the physical structures of composites have been modified through reinforcement hybridization; the appropriate design of roving, weave, and cross-orientation of fabric layers; and the development of 3D structures. This review focuses on the effects of modifying composites on their impact energy absorption capacity and other mechanical properties. It highlights the technologies used and their effectiveness for the three main fiber types: glass, carbon, and aramid. In addition, basic design considerations related to fabric selection and orientation are indicated. Evaluation of the literature data showed that the highest energy absorption capacities are obtained by using an STF or STG and an appropriate fiber reinforcement structure, while modifications using nanomaterials allow other strength parameters to be improved, such as flexural strength, tensile strength, or shear strength.

This work is a continuation of the publication [1], in which the torsional strength tests of samples made of polymer materials, loaded with torsional moment, which more and more often can be made with the use of incremental technologies, were carried out. The designed proprietary test stand, which was described in the publication [1], was used. A series of preliminary studies on the torsion of fittings with spline connections obtained using additive techniques were carried out. It was found, that a additive technologies have a clear impact on the torsional strength of the tested machine components, including the placement of the prototype relative to the 3D printing plane or the method of processing polymer material.

Appropriate selection of polymeric materials enables their wide application not only in machine construction elements, suspension and interior equipment of vehicles. Simultaneously with the development of new polymer materials, the processes of their processing developed. This also applies to incremental technologies. Rapid prototyping methods using 3D printers are largely based on various types of polymer materials. Currently, 3D printing is a well-known technique for producing functional elements, especially the Melt Extrusion Polymers (MEP) method, which is the oldest of the known techniques of spatial production. The main reason of the technology is designing and then manufacturing parts for many fields, including engineering, medicine, as well as the automotive and aviation industries. The article is a review of the literature on the use of composites based on thermoplastic polymers to develop new polymer materials used for 3D printing by MEP.

As part of the work, new polymer materials were used in 3D printing, which can be used in three technologies depending on the apparatus used: Fused Filament Fabrication (FFF), Melted and Extruded Manufacturing (MEM), Melt Extrusion Polymers (MEP). As part of the work, the properties of obtained polymer composites were examined. Polylactide (PLA) was used as the matrix, and powdered natural ground fillers were used as fillers: bamboo dust (PB), cork dust (PK) and wood dust (PD). In the first part of the work, filaments were received from the tested composites using the filament preparation line made by METACHEM in Torun for use in 3D printers. Samples for mechanical tests were obtained from the filaments thus received by means of an MEP printer and after granulation by injection molding. In the next part of the work, rheological, mechanical and structural properties of obtained composites were examined. It was found that the addition of natural fillers increased the fluidity of the obtained polymeric materials in the case of composite with addition of PK even by 48.73% compared to unfilled PLA. It was also observed that the composites obtained had lower Charpy impact strength, Rockwell hardness and tensile strength. Observation of the microstructure of the composites using SEM confirmed the even distribution of natural fillers in the polymer matrix, which proves well-chosen parameters of their homogenization in the polymer matrix.

Two types of graphite/diamond (GD) particles with different ash content was applied to prepare new electroconductive polylactide (PLA)-based nanocomposites. Four samples of nanocomposites for each type of GD particles with mass fraction 0.01, 0.05, 0.10, and 0.15 were prepared via an easily scalable method—melt blending. The samples were subjected to the studies of electrical properties via broadband dielectric spectroscopy. The results indicated up to eight orders of magnitude improvement in the electrical conductivity and electrical permittivity of the most loaded nanocomposites, in reference to the neat PLA. Additionally, the influence of ash content on the electrical conductivity of the nanocomposites revealed that technologically less-demanding fillers, i.e., of higher ash content, were the most beneficial in the light of nanofiller dispersibility and the final properties.