It is essential to combine current state-of-the-art technologies such as additive manufacturing with current ecological needs. Due to the increasing demand for non-toxic biodegradable materials and products, human society has been searching for new materials. Consequently, it is compulsory to identify the qualities of these materials and their behavior when subjected to various external factors, to find their optimal solutions for application in various fields. This paper refers to the biodegradable Polylactic acid (PLA)-based filament (commercially known as Extrudr BDP (Biodegradable Plastic) Flax) compared with the biodegradable composite material PLA-lignin filament whose constituent’s trade name is Arboblend V2 Nature as a lignin base material and reinforcement with Extrudr BDP Pearl, a PLA based polymer, 3D printed by Fused Deposition Modeling technology. Certain mechanical properties (tensile strength, bending strength and DMA—Dynamic Mechanical Analysis) were also determined. The tribology behavior (friction coefficient and wear), the structure and the chemical composition of the biodegradable materials were investigated by SEM—Scanning Electron Microscopy, EDX—Energy Dispersive X-Ray Analysis, XRD—X-Ray Diffraction Analysis, FTIR—Fourier Transform Infrared Spectrometer and TGA—Thermogravimetric Analysis. The paper also refers to the influence of technological parameters on the 3D printed filaments made of Extrudr BDP Flax and the optimization those of technological parameters. The thermal behavior during the heating of the sample was analyzed by Differential scanning calorimetry (DSC). As a result of the carried-out research, we intend to recommend these biodegradable materials as possible substituents for plastics in as many fields of activity as possible.

Polyethylene terephthalate (PET) is used worldwide for packing, and for this reason, it is the main material in plastic waste. The paper uses granules of recycled PET (R-PET) as raw material for producing filaments for 3D printing, subsequently used for printing the test specimens in different ways: longitudinally and at angles between 10° and 40° in this direction. Both the filaments and the printed specimens experience thermally driven shape memory effect (SME) since they have been able to recover their straight shape during heating, after being bent to a certain angle, at room temperature (RT). SME could be reproduced three times, in the case of printed specimens, and was investigated by cinematographic analysis. Then, differential scanning calorimetry (DSC) was used, in R-PET granules, filaments and 3D printed specimens, to emphasize the existence of glass transition, which represents the governing mechanism of SME occurrence in thermoplastic polymers, as well as a recrystallization reaction. Subsequently, the paper investigated the 3D printed specimens by dynamic mechanical analysis (DMA) using a dual cantilever specimen holder. Temperature (DMA-TS) and isothermal scans (DMA-Izo) were performed, with the aim to discuss the variations of storage modulus and loss modulus with temperature and time, respectively.

Special materials are required in many applications to fulfill specific medical or industrial necessities. Biodegradable metallic materials present many attractive properties, especially mechanical ones correlated with good biocompatibility with vivant bodies. A biodegradable iron-based material was realized through electric arc-melting and induction furnace homogenization. The new chemical composition obtained presented a special property named SME (shape memory effect) based on the martensite transformation. Preliminary results about this special biodegradable material with a new chemical composition were realized for the chemical composition and structural and thermal characterization. Corrosion resistance was evaluated in Ringer’s solution through immersion tests for 1, 3, and 7 days, the solution pH was measured in time for 3 days with values for each minute, and electro-corrosion was measured using a potentiostat and a three electrode cell. The mass loss of the samples during immersion and electro-corrosion was evaluated and the surface condition was studied by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). SME was highlighted with differential scanning calorimetry (DSC). The results confirm the possibility of a memory effect of the materials in the wrought case and a generalized corrosion (Tafel and cyclic potentiometry and EIS) with the formation of iron oxides and a corrosion rate favorable for applications that require a longer implantation period.

The medical applications of degradable iron-based biomaterials have been targeted by re-searchers due to their special properties that they present after alloying with various elements and different technological methods of obtaining. Compared to other biodegradable materials, iron-based alloys are designed especially for the low production costs, the non-magnetism obtained by alloying with Mn, and the shape memory effect (SME) following the alloying with Si, which is necessary in medical applications for which it could replace nitinol successfully. Alloying with new elements could improve the mechanical properties, the degradation rate, and the transformation temperatures corresponding to the SME. This paper presents the results from the study of FeMnSi-Al alloy as a biodegradable material. The X-ray diffraction (XRD) method was used to identify the phases formed in the experimental Fe-Mn-Si-Al alloy, and the SME was studied by differential scanning calorimetry (DSC). In vitro tests were performed by immersing the samples in Ringer’s biological solution for different time intervals (1, 3, and 7 days). The chemical composition of the samples, as well as the compounds resulting from the immersion tests, were evaluated by energy dispersive X-ray (EDS). Scanning electron microscopy (SEM) was used for the microstructural analysis and for highlighting the surfaces subjected to contact with the electrolyte solution. The corrosion rate (CR, mm/yr.) was calculated after mass loss, sample surface area, and immersion time (h) (at 37 °C). Samples were subjected to electro-corrosion tests using electrochemical impedance spectroscopy (EIS) and Tafel linear and cyclic potentiometry.