The aim of this work was to produce filaments of PLA/PBAT and NPK fertilizer adsorbed on organophilized bentonite intended for application in the prototyping of biodegradable agricultural artifacts in 3D printing, using the Fused Deposition Modeling (FDM) technique. This is the first time that we have reported this composite for a 3D printing approach. Systems containing PLA/PBAT, organobentonite and NPK were initially processed in an internal mixer and later extruded as filaments in a single-screw extruder. The prototypes were printed by FDM. Structural, morphological and thermal properties, as well as NPK releasing, were investigated. The results suggest that exfoliated and/or intercalated nanocomposites were obtained by the organoclay addition to the PLA/PBAT blend. The morphological analysis revealed a good surface quality of the impressions. Systems containing organobentonite released approximately 22% less fertilizer in 24 h compared to the systems without organobentonite. This difference is due to the higher concentration of nanoparticles that generate more barriers to the diffusion of NPK. The release data for these systems had a better fit to the kinetic model of Korsmeyer-Peppas. Thus, studied filaments have the potential to retard the release of fertilizer and are suitable for further development of structures for agricultural applications by FDM.

In this work, recycled poly(ethylene terephthalate) (PETR) was blended with virgin high-density polyethylene (HDPE) in an internal mixer in an attempt to obtain a material with improved properties. A compatibilizer (PE-g-MA) and a chain extender (Joncryl) were added to the PETR/HDPE blend and the rheological and thermal properties of the modified and unmodified blends as well as those of virgin PET with virgin HDPE (PETV/HDPE). All the blends were characterized by torque rheometry, differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The data obtained indicate that the incorporation of either the chain extender or the compatibilizer agent led to increases in torque (and hence in viscosity) of the blend compared to that of the neat polymers. The joint incorporation of the chain extender and compatibilizer further increased the viscosity of the systems. Their effect on the crystallinity parameters of HDPE was minimal, but they reduced the crystallinity and crystallization temperature of virgin and recycled PET in the blends. The thermal stability of the PETR/HDPE blend was similar to that of the PETV/HDPE blend, and it was not affected by the incorporation of the chain extender and/or compatibilizer.

In this work, blends based on poly (lactic acid) (PLA)/acrylonitrile-butadiene-styrene (ABS) compatibilized with maleic anhydride-grafted (SEBS-g-MA) were prepared in a co-rotational twin-screw extruder by varying the concentrations of the compatibilizing agent. The influence of the compatibilizing agent on the morphology, mechanical, thermal, thermomechanical, and rheological properties of the prepared materials was analyzed. The effect of annealing on the properties of the blends was also investigated using injection-molded samples. The X-ray diffraction (XRD) results proved that the increments in crystallinity were an effect of annealing in the PLA/ABS/SEBS-g-MA blends, resonating at higher heat deflection temperatures (HDTs). The impact strength of the PLA/ABS blends compatibilized with 10 wt% SEBS-g-MA was significantly increased when compared to the PLA/ABS blends. However, the hardness and elastic modulus of the blends decreased when compared to neat PLA. The refined morphology shown in the scanning electron microscopy (SEM) analyses corroborated the improved impact strength promoted by SEBS-g-MA. The torque rheometer degradation study also supported the increased compatibility between SEBS-g-MA, PLA, and ABS. The TGA results show that the PLA/ABS and PLA/ABS/SEBS-g-MA blends are more thermally stable than the neat PLA polymer at higher temperatures. The results showed that the ideal composition is the heat-treated PLA/ABS/SEBS-g-MA (60/30/10 wt%), given the high impact strength and HDT results. The results of this work in terms of mechanical improvement with the use of compatibilizers and annealing suggest that the PLA/ABS/SEBS-g-MA system can be used in the production of 3D-printing filaments.

For the first time, ultrafiltration (UF) green membranes were prepared through a sustainable route by using PLA as a biopolymer and dihydrolevoclucosenone, whose trade name is Cyrene™ (Cyr), dimethyl isosorbide (DMI), and ethyl lactate (EL) as biobased solvents. The influence of physical-chemical properties of the solvent on the final membrane morphology and performance was evaluated. The variation of polymer concentration in the casting solution, as well as the presence of Pluronic^® (Plu) as a pore former agent, were assessed as well. The obtained results highlighted that the final morphology of a membrane was strictly connected with the interplaying of thermodynamic factors as well as kinetic ones, primarily dope solution viscosity. The pore size of the resulting PLA membranes ranged from 0.02 to 0.09 μm. Membrane thickness and porosity varied in the range of 0.090–0.133 mm of 75–87%, respectively, and DMI led to the most porous membranes. The addition of Plu to the casting solution showed a beneficial effect on the membrane contact angle, allowing the formation of hydrophilic membranes (contact angle < 90°), and promoted the increase of pore size as well as the reduction of membrane crystallinity. PLA membranes were tested for pure water permeability (10–390 L/m² h bar).

Objective: The study aimed to characterize sugarcane bagasse ash (SCBA) regarding its chemical, physicochemical, thermal, structural, crystalline, and morphological properties, in order to evaluate its potential application as a mineral filler in polymer composites. Theoretical Framework: The literature highlights the relevance of agro-industrial residues as an alternative source of mineral fillers in polymers, mainly due to their availability, low cost, and sustainability aspects. SCBA is recognized for its high silica content, as well as metallic oxides that can influence mechanical and thermal properties (Barrera et al., 2021). Method: SCBA characterization was conducted using various techniques. Chemical composition was determined by XRF, while thermal stability was assessed by TGA. FTIR was employed to identify functional groups, and XRD determined the crystalline phases and degree of crystallinity of the material. Finally, particle morphology was examined using SEM. Results and Discussion: The results indicated that SCBA has a chemical composition dominated by SiO₂, followed by K₂O, Fe₂O₃, and CaO, with no toxic elements detected. Thermal analysis demonstrated high stability, while FTIR confirmed the predominance of silica. XRD revealed a crystallinity degree of 50.26%. SEM micrographs showed fibrous, rough, and porous particles, with preserved biomass structures, favoring dispersion and interfacial adhesion in polymer matrices. Overall, these results reinforce the feasibility of SCBA as an alternative mineral filler in sustainable composites. Research Implications: The findings confirm that SCBA exhibits chemical, structural, and morphological characteristics compatible with its use as a polymer filler. Its thermal stability and high silica content underscore its potential for developing sustainable materials with enhanced properties. Originality/Value: This work contributes to expanding knowledge on the use of SCBA as an alternative mineral filler, integrating different characterization techniques. Its originality lies in demonstrating its technical potential while aligning innovation, cost-effectiveness, and reduction of environmental impacts.

Objective: This study aims to evaluate the effects of pH, ammonium sulfate supplementation, and refrigeration on fermentation performance in sugarcane molasses, with the goal of optimizing ethanol production under simulated industrial conditions. Theoretical Framework: The research builds on key concepts in biofuel production, emphasizing the role of pH, nutrient supplementation, and temperature control in influencing yeast metabolism and fermentation efficiency. Theories on enzymatic activity and nutrient absorption (Vidal et al., 2013; Gutierrez, 1993) provide the foundation for understanding the interactions between these factors. Method: A full 2³ factorial design was employed, evaluating the effects of pH (3.5 and 5.0), supplementation (0.0 and 1.0 g/L), and refrigeration (with or without) on fermentation efficiency, process efficiency, ethanol productivity, and substrate-to-cell conversion in a microdistillery. Analytical methods included spectrophotometry, refractometry, and chromatography. Results and Discussion: The results indicate that fermentation conditions with pH 3.5, without supplementation, and with refrigeration yielded the best performance, with significant increases in ethanol productivity and fermentation efficiency. The interaction between variables suggests that these factors should be considered jointly to optimize the process. Research Implications: The findings offer practical insights for improving fermentation in industrial biofuel production, particularly in optimizing conditions for ethanol yield and process efficiency under near-industrial conditions. Originality/Value: This study contributes by using a microdistillery to simulate industrial conditions, providing more accurate data for scaling ethanol production. It adds value by highlighting how specific combinations of pH, supplementation, and refrigeration can improve biofuel sustainability.