The influence of fiber orientation on the mechanical behavior of a polymer matrix composite reinforced with natural jute fibers is investigated in this study. Two fiber orientation configurations are examined: the first involves woven fibers aligned in the direction of testing, while the second considers a 45° orientation. The research involves manufacturing composite plates using jute fabric with the mentioned orientations, followed by cutting rectangular specimens for tensile testing to determine which orientation yields superior properties. Displacement fields are measured using a digital image correlation technique, synchronized with load data obtained from a universal testing machine equipped with a load cell to obtain stress–strain curves for each configuration. Results indicate that 0° specimens achieve higher stress but lower strain compared to 45° specimens. This research contributes to understanding the optimal fiber alignment for enhancing the mechanical performance of fiber-reinforced polymer composites.

Metallic nanoparticles with virucidal properties dispersed in a polymeric matrix have gained prominence in the scientific community as a rapid and effective alternative that employs the additive manufacturing (AM) or 3D printing method. This study aims to produce filaments for 3D printing using polymer nanocomposites based on polylactic acid (PLA) and copper nanoparticles (CuNPs) in different proportions. The virucidal activity of various proportions of nanoparticles in PLA was investigated. The composites were produced following a mixture design (DOE) with concentrations ranging from 1% to 2% copper nanoparticles, which were blended with PLA using a single-screw extruder. The samples were characterized by thermogravimetry (TG), differential scanning calorimetry (DSC), tensile strength testing, and fracture analysis using scanning electron microscopy (SEM). A thermal analysis of the composites indicated that the CuNPs contributed to an increase in the degradation temperature and crystallization of the PLA. Sample S7 (1.25% of CuNPs) exhibited a 4% increase in the degradation temperature compared to pure PLA. The best tensile strength results were observed in sample S7 (1.25% of CuNPs), 30% more than sample S3 (1.33% of CuNPs) due to good material cohesion, as evidenced by microscopy analyses. Regarding virucidal analyses, most composites demonstrated virus inhibition activity.

3D printing with biodegradable polymers such as polylactic acid (PLA) is a sustainable alternative to conventional petroleum-derived plastics. However, improving the mechanical properties of PLA remains a challenge. This study explores the incorporation of chemically treated hemp fibers to improve the interfacial adhesion and mechanical strength of PLA filaments. Samples with PLA and hemp were prepared by subjecting the fibers to cationization treatment with (3-chloro-hydroxypropyl) tri-methylammonium (EPTA) and functionalization with glycidyl methacrylate (GMA). EPTA improves adhesion mainly through surface modification, increasing reactive functional groups in cellulose, while GMA improves interfacial adhesion by forming covalent bonds with both the fiber and PLA and improves the dispersion of the fiber in the matrix. Mechanical properties were evaluated by tensile testing, as well as fracture morphology by scanning electron microscopy (SEM) and X-ray energy dispersive analysis (EDS). The results showed that the addition of untreated hemp significantly reduced the strength of PLA, but cationization with EPTA improved interfacial adhesion and increased tensile strength by 615%. The combination of treated fibers and GMA further optimized the mechanical properties, reaching values similar to pure PLA. These findings indicate that the chemical modification of natural fibers facilitates their integration into PLA filaments for 3D printing, promoting sustainable materials without compromising mechanical performance.

A characterization of composite materials of a polyester matrix reinforced with natural fibers of Cuban henequen and organophilized Cuban bentonite was carried out, the experimental results of which are used to formulate, implement, and validate a scalar damage model. The fibers were added on a weight basis of 15, 20, and 25% as a reinforcing material, and organophilized Cuban bentonite, in amounts of 3, 5, and 7% by weight, was added. Samples containing only polymer and fibers showed the best mechanical performance for 25% of fiber, with increases of 51% in the tensile strength and 169% on the impact resistance. Samples containing polymer and clay showed the best results for 5% of bentonite, with increases of 89% in the tensile strength and 83% on the impact resistance, and samples containing 25% fiber and 5% clay were also prepared and achieved a 98% increase in the tensile strength and 219% in the impact strength. The scalar damage model deals with an internal variable, which corresponds to the damage variable, together with a failure surface that allows identifying the mechanical state of the material dependent on the mechanical stress, obtaining an adequate correlation with the results of the experimental tests.