This study investigates the sustainable use of Eucalyptus spp. bark through different chemical (hydrothermal, acid, alkaline, and bleaching) and physical (milling) pretreatments in the production of sustainable films. Valorization of agro-industrial residues and the demand for sustainable materials pose challenges for environmentally responsible solutions. Eucalyptus spp. bark, rich in cellulose, hemicellulose, and lignin, is a promising source for creating sustainable materials like films. In this study, the use of chemical and physical treatments aims to optimize biomass extraction and improve the chemical, thermal, mechanical, and optical properties of the films. The films showed an excellent light barrier capacity, with a transmittance below 1%. Crystallinity indices varied with the pretreatment: 8.15% for hydrothermal, 7.01% for alkaline, 7.63% for acid, and 10.80% for bleaching. The highest crystallinity value was obtained through bleaching, by removing amorphous components like lignin and hemicellulose. The alkaline pretreatment yielded stronger films (maximum stress of 8.8 MPa, Young’s modulus of 331.3 MPa) owing to the retained lignin and the hemicellulose reinforcing the material. This study contributes to the field of sustainable development by converting residues into valuable materials and by advancing the circular economy. The films’ specific properties make them suitable for applications like sustainable packaging, addressing environmental and industrial challenges.

This study investigates low‐density green polyethylene (LDPE) nanocomposites reinforced with bamboo‐derived cellulose nanocrystals (CNCs) and compatibilized with polyethylene‐graft‐maleic anhydride (PE‐g‐MA). Four materials were prepared by melt extrusion and injection molding (neat LDPE; LDPE with 1.0 and 1.5 wt% CNCs; and LDPE with 1.0 wt% CNC + 1.0 wt% PE‐g‐MA) and evaluated by thermal, mechanical, and structural analyses. Fourier‐transform infrared spectroscopy (FTIR) indicated interactions between maleic‐ anhydride groups and CNC hydroxyls, supporting improved interfacial compatibility. X‐ray diffraction (XRD) showed increased crystallinity in CNC‐containing samples, consistent with a nucleating effect. Thermogravimetric analysis/derivative thermogravimetry revealed single‐step LDPE decomposition with an upward shift of the degradation‐rate peak upon CNC addition; residues remained below at these low loadings. Under uniaxial tension, stiffness increased significantly at 1.5 wt% CNC and in the compatibilized composite, while tensile strength improved only with PE‐g‐MA; elongation decreased with CNCs irrespective of compatibilizer, remaining highest for neat LDPE. After accelerated aging (UV + humidity), modulus and strength exhibited modest declines across all materials, comparatively larger in the compatibilized system, suggesting time‐dependent changes at the CNC‐matrix interface. Overall, bamboo‐CNC/PE‐g‐MA provides a sustainable route to tailor thermal performance and load‐bearing response of LDPE for applications that prioritize stiffness and thermal resistance over ductility.

O artigo apresenta o estudo comparativo entre três diferentes tipos de lignina recuperadas de licores negros de pré-tratamento de biomassas para a produção de etanol de segunda geração, sendo elas ligninas de arroz, arundo e de mistura de biomassa. Como enfoque principal aborda a caracterização térmica de ambas as ligninas, comparando-as entre si. As ligninas foram recuperadas através de precipitação com H2SO4 50% v/v e após processo de lavagem, procederam-se análises espectrofotométricas no infravermelho (FTIR), análise termogravimétrica (TGA) e calorimetria exploratória diferencial (DSC). Através da análise FTIR foram identificados os grupos funcionais OH, C-C, C=O e C=C que são característicos de ligninas. Entretanto as análises por TGA indicaram que as três ligninas apresentaram teores semelhantes para umidade, e diferenças significativas com relação aos teores de voláteis e cinzas, confirmando a complexidade estrutural da lignina. Associada à análise termogravimétrica as ligninas foram submetidas à análise DSC para determinação da perda de energia, onde apesar de apresentar dois eventos endotérmicos a lignina de arundo apresentou uma menor absorção de energia em relação às ligninas de arroz e de mistura de biomassas.

Currently, single‐screw extrusion offers a versatile and accessible route to produce polymer filaments for additive manufacturing. In this work, 1.75‐mm filaments based on polypropylene (PP)/styrene‐ethylene‐butylene‐styrene (SEBS) blends compatibilized with maleic anhydride (MA) and filled with zinc oxide (ZnO) were compounded and processed using a digitally controlled bench‐top mini‐extruder (220°C–240°C). The materials were evaluated in terms of chemical (FTIR), structural (XRD), morphological (SEM), thermal (TGA/DTA), and mechanical properties, together with filament dimensional stability and preliminary fused filament fabrication (FFF) performance. FTIR indicates interfacial interactions involving MA and ZnO, while XRD confirms preservation of α‐iPP and retention of wurtzite ZnO. Crystallinity increased from 43.6% (PP/SEBS) to 71.3% (PP/SE‐ BS/MA/ZnO). SEM analysis revealed significant refinement of SEBS‐rich domains, with the average equivalent diameter decreasing from 7.57 ± 4.79 μm to 1.34 ± 0.58 μm. TGA results show that all formulations are thermally stable within the FFF processing window, with PP/SEBS/MA/ZnO presenting the highest stability. Mechanical testing demonstrated a synergistic effect between MA and ZnO, improving strength and ductility. Preliminary FFF trials confirmed stable extrusion, consistent deposition, and good dimensional accuracy after calibration. These results demonstrate a practical small‐scale route for producing PP/SE‐BS‐based filaments with improved morphology, thermal stability, and printability.

Arundo donax L. is a plant with great potential as lignocellulosic biomass, being a promising source for the development of biodegradable materials. This study evaluated the effects of different chemical pretreatments (H₂SO₄, NaOH, and NaClO) combined with dry milling on the physicochemical properties of biomass. Pretreatment with NaClO was the most effective in removing lignin, reducing its content to 0.2%, while increasing the cellulose content to 67%. Pretreatment with H₂SO₄, although retaining a higher lignin content (24%), resulted in the greatest reduction in particle size, reaching a mean diameter (Dm) of 44.31 µm after 20 h of milling. Density analysis revealed that the raw samples reached a maximum density of 0.218 g/cm³ after 20 h of milling, with the pretreated samples showing lower densities due to the removal of structural components. Thermal analysis showed mass losses of up to 66.4% for samples pretreated with NaClO after 10 h of milling, indicating significant structural changes and improved thermal stability. Morphological analysis via SEM demonstrated elongated and fine particles, with acid pretreatment resulting in the most pronounced structural changes. These findings highlight the efficiency of combining chemical and physical pretreatments to modify the structure of A. donax L., optimizing its properties for the production of high-performance biodegradable materials.

Pectin films are promising renewable materials for biodegradable coatings; however, their high hydrophilicity and limited resistance to ultraviolet (UV) radiation restrict practical applications. This work investigated the influence of kraft lignin (0–5 wt%) on the structure–property relationships of grape-derived pectin films before and after accelerated UV exposure. Structural organization (XRD and FTIR), photostability (CIELAB colorimetry and CIE chromaticity), wettability, water-vapor absorption, surface morphology, soil-burial disintegration, and integrated multifunctional performance were evaluated. Lignin improved resistance to UV-induced structural changes, reducing the relative loss of apparent crystallinity from 52.76% for neat pectin to less than 7% for films containing at least 0.1 wt% lignin, while substantially decreasing UV-induced color changes. Increasing lignin content also reduced surface wettability, water-vapor uptake, and soil-burial mass loss; nevertheless, all formulations exhibited more than 50% mass loss after 120 h of soil burial. Exploratory CRITIC–TOPSIS analysis identified Pec/Lig₁ as the highest-performing formulation, whereas Pec/Lig_0.1 provided the most compositionally efficient balance among photostability, moisture resistance, structural stability, soil-burial disintegration, and lignin consumption. These findings demonstrate that lignin governs the trade-offs among structural stability, photostability, moisture resistance, soil-burial disintegration, and additive consumption, establishing composition–structure–property–durability relationships that provide practical design guidance for candidate functional coatings for cellulose- and paper-based substrates.