Continuous carbon fiber (cCF)-based 3D-printed polymer composites are known for their excellent flexural properties; however, the optimization of the overall process is still desired, depending on the material types involved. Here, the improved manufacturing of cCF-based composites is reported, considering virgin polyamide (PA) and postindustrial waste polypropylene (PP), and the parameters affecting the material properties are evaluated. Firstly, the prepregnation technique was optimized to manufacture cCF polymer filaments with various fiber-to-polymer ratios. Secondly, the fused filament fabrication (FFF) technique was optimized. It was observed that the layer height needs to be sufficiently low for proper interlayer adhesion. The influence of the printing temperature is more complicated, with filaments characterized by a lower fiber-to-polymer ratio requiring a higher nozzle diameter and higher temperatures for efficient printing; and for lower diameters, the best flexural properties are observed for parts printed at lower temperatures, maintaining a high interspace distance. Plasma treatment of the cCF was also explored, as was annealing of the produced parts to enhance the flexural properties, the latter being specifically interesting for the PP-based composite due to a lower wetting caused by a higher viscosity, despite supportive interfacial interactions. Eventually, overall guidelines were formulated for the successful production of cCF-based composites.

Composites are gaining widespread market interest due to their outstanding mechanical properties and light weight. However, this growth is hindered by the lack of sustainable recycling solutions. This research aims to integrate reversible chemistries to advanced carbon fiber‐reinforced composite materials for recycling in a so‐called eco‐design, circular approach. Diene and dienophile reactions are generated at the surface of the carbon fiber allowing a bond–debond interaction with the epoxy matrix. The application of the Diels–Alder adduct on the fiber modifies its polarity and structure. This research assesses a biobased and synthetic epoxy equivalent and demonstrates that this newly developed interphase chemistry has a direct impact on the crosslinking efficiency of the resin, as well as on their interlaminar properties. Furthermore, it has been observed that depending on the type of resin, these changes can have differing impacts on final properties of the composite, reducing the crosslinking density up to 50% in some modifications while in others the T_g remains constant.

Plasma technology is increasing its applications in the textile industry for conferring surface functionalities through greener processes. In this study, plasma treatments are studied to improve the wettability of mycelium-based material, an emerging material with a lot of potential in the near future. The plasma effect was characterized by assessing the added functionality (wettability) and inspecting surface modifications with different techniques, such as scanning electron microscopy (SEM) and X-Ray photoelectron spectroscopy (XPS). Low pressure plasma (LPP) treatments were successfully applied into the mycelium-based material and optimal power of discharge and treatment time were set for this material (750 W, 17.5 min). With the optimized LPP treatments, the water absorption capacity of mycelium-based material was improved by 2000% and some surface morphological modifications were observed by SEM analysis. On the other hand, XPS analysis demonstrated how the plasma treatment changes the surface composition.