Additive manufacturing and the development of electro-conductive nanocomposites via fused deposition modeling (FDM) are prominent research topics. Polymers such as polylactic acid (PLA), polyhydroxyalkanoates (PHAs), and PLA-PHA blends are commonly employed to this aim. To achieve electrical conductivity, fillers such as carbon nanotubes (CNTs) and carbon black are commonly incorporated. The analysis of the filaments prior to FDM is particularly relevant, as their electromechanical properties directly influence the final performance of FDM-manufactured parts. However, there is a notable lack of research addressing this aspect. This study focuses on manufacturing CNT/PLA and CNT/PLA-PHA conductive filaments and their electromechanical characterization. The filaments are produced by melt blending followed by extrusion and are used to fabricate monolayer tensile coupons via FDM in order to evaluate and compare their electromechanical behavior. The inclusion of CNTs led to a slight increase in tensile strength in both the filament and the FDM-manufactured specimens, but elongation at break decreased in the FDM coupons. A reduction of three orders of magnitude in the electrical conductivity of the filaments was observed after FDM, along with a significant change in their piezoresistive response. These findings indicate that, while the incorporation of CNTs may improve tensile strength, the FDM process reduces electrical conductivity and alters the material’s electromechanical sensitivity. Differential scanning calorimetry indicated polymer degradation, which is associated with thermal processes during extrusion and FDM. Such degradation resulted in a variation in the mechanical properties of the nanocomposites after FDM. These results underscore the importance of characterizing the polymeric filaments and the final FDM-manufactured parts to better understand and optimize the functional performance of conductive components produced by additive manufacturing.

Municipal solid waste (MSW) poses significant risks to both environmental health and human well-being. Therefore, devising innovative and sustainable solutions for transforming MSW into valuable resources is crucial. MSW composition exhibits marked differences between developed and developing nations. While MSW in developing countries largely comprises organic matter such as food waste, wood, foliage, and agricultural residues, developed countries produce MSW dominated by inorganic materials like plastics, paper, metals, and electronic devices. Globally, MSW encompasses a diverse array of materials including household refuse, agricultural remnants, metals, paper, glass, plastics, electronics, inert substances, and miscellaneous debris. Current waste management strategies worldwide heavily favor landfilling, which accounts for approximately 70% of generated MSW. Alternative treatment methods include classified recycling, incineration, pyrolysis, gasification, composting, and anaerobic digestion.

This research investigates a cost-effective chemical process for converting waste cans, a major component of MSW, into active iron oxide nanoparticles. The synthesized nanoparticles were characterized using techniques such as X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). To highlight the potential applications of these nanoparticles, they were incorporated into the fabrication of a magnetic polymer, utilizing magnetite nanoparticles as stabilizers in an emulsion template. This novel material holds promise for use in various fields, including diagnostic devices and smart systems.

Currently, there has been a growing interest in the development of smart and active packaging materials that can protect food from external environmental factors. Ideally, these materials should combine antibacterial and antioxidant properties with biodegradability. However, most biodegradable and biocompatible polymers inherently lack active properties. As a result, it becomes essential to incorporate functional compounds that can enhance their protective capabilities, improve interaction with food, and ultimately extend shelf life [1].
Polylactic acid (PLA) is a well-known biocompatible and biodegradable polymer. PLA-based nanofibrous materials can be manufactured by mixing the polymer with various additives or particles to tailor their final properties [2]. Among these additives, quercetin, a naturally occurring polyphenol found in plants, is recognized for its strong antioxidant activity, which stems from its redox potential and structural configuration [3]. Incorporating quercetin into PLA nanofibers holds promise for the development of more effective smart packaging solutions.
This study aims to investigate the influence of quercetin on the properties of PLA-based nanofibers. The nanofibers were prepared by mixing a PLA solution with quercetin powder and processing the mixture using Solution Blow Spinning (SBS) [4,5]. To examine the effect of quercetin concentration, samples were prepared with varying quercetin contents (0.0, 1.0, 3.0, 5.0, and 7.0 wt%).
A comprehensive series of characterizations, including antioxidant, structural, morphological, antibacterial, and water vapor transmission tests, was conducted to evaluate the influence of quercetin on the final properties.
The outcomes of these characterizations were used to assess the effect of quercetin on the performance of the PLA nanocomposites. The findings provide insights into the potential application of these materials in active food packaging systems.

Intro: Production of composite parts requires the presence of proper tools, often made of polyurethane boards, which imply the use of harmful substances, such as isocyanates. Moreover, the standard approach for tooling manufacturing is subtractive, generating a massive amount of waste: as a thermosetting material, PU boards are not easily recycled nor re-used; hence, they are often landfilled, increasing the burdens associated with composite manufacturing.
Methods: TOOL4LIFE, an EU-Life project, aims to introduce additive manufacturing and design optimization in composite tooling for the automotive industry, combined with the use of thermoplastic materials. The innovations simplify the tooling (i.e. no need of master models), reduce waste scrap (i.e. direct 3-D printing), and allow for tool recycling at the EoL, in a sustainable perspective.
Results: Finite Element (FE) topology optimization analyses supported the definition of a proper design shape for specific tool application, reducing the amount of material mass required and optimizing the 3D printing process. Life Cycle Assessment (LCA) applied to the selected shape confirmed the reduction in associated environmental impacts with respect to the baseline PU tool.
Conclusions: The combination of FE analysis and LCA, along with the selection of thermoplastic polymers (i.e. PC, ABS), supported a transition towards sustainable materials and processing in composite tooling. The application in the automobile sector, whose design and requirements are challenging, is proficient and suggests a potential wider application in other hi-tech industries. This approach proves that sustainability in composites can be achieved without sacrificing technological performance and feasibility.
Acknowledgement: The TOOL4LIFE project has received funding from the European Union’s Programme for Environment and Climate Action (LIFE) under grant agreement N° 101074299-TOOL4LIFE- LIFE-2021-SAP-ENV. The authors declare no conflict of interest.

Introduction. Growing industry demand, together with rising pollution and the depletion of phosphorus, is moving the scientific community towards the development of flame-retardant (FR) epoxy nanocomposites (ENCs) containing low P contents and more sustainable additives.

Methods. High-resolution transmission electron microscopy (HRTEM) analysis was carried out to study the morphology of ENCs. Cone calorimetry (CC) and UL-94 vertical flame spread tests were performed to investigate the fire response of all ENCs.

Results. The reaction of DGEBA (Bisphenol A diglycidyl ether)- or Novolac-based resins with APTES (3-aminopropyltriethoxysilane) allows the production of organic–inorganic silanized epoxy moieties. The hybrid moieties can condense with tetraethyl orthosilicate (TEOS), a silica precursor, to form an in situ silica phase through sol–gel reactions. HRTEM analysis revealed that in the case of DGEBA, the silica phase was composed of well-ordered multi-lamellar nanoparticles (NPs). In contrast, the investigation of Novolac highlighted that fully amorphous silica NPs were embedded in the hybrid co-continuous polymer network. The incorporation of DOPO-based FRs into silica–epoxy systems based on DGEBA/Novolac resin produces aliphatic nanocomposites with high transparency, no-dripping UL-94-V0 rating, and a strong decrease (up to 80%) in the peak of the heat release rate in CC tests, with up to 3 wt.% of P loading. Regarding Novolac, the transparency is remains even at loadings of silica NPs beyond 4 wt.%, thanks to their amorphous nature. More waste-to-wealth approaches involve the use of humic acids or biochar from spent coffee grounds, together with ammonium polyphosphate and urea, in APTES-modified DGEBA-based epoxy systems to obtain no-dripping self-extinguishing systems, even with only 1 wt.% of P content.

Conclusions. The sol–gel in situ generation of inorganic phases has been explored in combination with DOPO-based FRs, bio-wastes, and other synergists to prepare no-dripping self-extinguishing (V-0 rating in UL-94 flammability tests) aliphatic ENCs, even keeping P at low loadings (1-3 wt.%).

Low-density polyethylene (LDPE) is a widely used thermoplastic polymer in the production of plastic bags and pipes due to its flexibility, chemical resistance, and low cost. However, its recalcitrance to degradation contributes significantly to global plastic pollution, underscoring the need for strategies to enhance its breakdown. This study assessed the physicochemical alterations in LDPE beads after 30 days of exposure to native Colombian fungal strains of Fusarium oxysporum (FOCIC01), under conditions where LDPE served as the sole carbon source. The experimental setup included mineral salt medium inoculated with the FOCIC01 strain. Following incubation, LDPE beads were separated from fungal biomass via sequential washing with 1% SDS, rinsing with 70% ethanol and sterile distilled water, followed by sonication to ensure thorough removal of biofilm and surface residues prior to analysis. Structural and chemical changes in the polymer were analysed through Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR), and Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF). SEM revealed pronounced surface erosion, fissures, and pitting in LDPE beads exposed to the fungal strain, in contrast with the smooth, intact control beads. FTIR analysis showed the appearance of new absorption bands corresponding to hydroxyl (–OH) and carboxyl (–COOH) groups, indicating oxidative modification of the polymer structure. These spectral changes suggest the occurrence of oxidative degradation processes, likely facilitated by fungal enzymatic activity. MALDI-TOF mass spectrometry, performed on the supernatants of the degradation assays, revealed fragmentation patterns indicative of partial depolymerisation, with signals consistent with low-molecular-weight polyethylene oligomers. The integration of these complementary analytical approaches demonstrates the potential of native F. oxysporum to initiate degradation of LDPE through extracellular mechanisms. This work provides new insights into polymer–fungus interactions and supports the development of fungal-based biodegradation strategies for synthetic plastic waste.

This paper explores the ballistic impact behavior of a 1/1 fabric composed of aramid yarns using numerical simulations in ANSYS Explicit Dynamics. The main objective is to analyze the influence of boundary conditions applied to the yarns and the impact velocity on the structural response of the material under the action of a 9 mm FMJ (Full Metal Jacket) projectile. The fabric is modeled at the meso scale, where the structure of the yarn fabric is represented explicitly, without detailing the individual filaments in the composition of each yarn. The yarns are defined as elastoplastic materials with bilinear isotropic behavior, using parameters obtained from the literature for Kevlar or Twaron aramid fibers. Four fastening scenarios were analyzed: four-edge fastening, two-edge fastening by blocking the transverse faces of the yarns, and fastening applied over a length of 1.5 mm at the ends of the yarns. Five impact speeds were investigated: 430 m/s (according to the NIJ standard), 330 m/s, 320 m/s, 220 m/s, and 120 m/s. The results obtained include the maximum deformation of the fabric, the distribution of stresses, and the analysis of projectile penetration. The simulations indicate a clear correlation between impact velocity, fastening type, and the fabric's ability to dissipate energy and resist penetration. The study contributes to the understanding of the protective mechanisms of ballistic textiles and supports the development of more effective configurations. The results obtained are validated with papers from the specialized literature.

In recent decades, the use of polyhydroxyalkanoate biopolymers has drawn increasing attention. Still, one of the biggest challenges that hinders their wide applications is the fine-tuning of their photooxidative aging. Therefore, the objective of this study is to investigate the effect of Agave Americana fibers (AFs) before and after surface treatment with sodium bicarbonate (NaHCO₃) on the accelerated photooxidation of PHBHHx using a SEPAP 24-48 enclosure. Biocomposite samples are prepared by melt compounding at a filler content of 30 wt.%. Colorimetric analysis reveals a yellowing effect of neat PHBHHx after 216h of exposure to UV rays, which is attributed to the formation of carbonyl groups. For the untreated biocomposites (PAF), they show a browning in color, while the PHBHHx-treated AF (PAFB) shows a lighter surface. The former process is attributed to the presence of lignin, whereas the latter is owing to the successful removal of lignin and hemicellulose by NaHCO₃. Changes in the chemical structure are assessed via FTIR-ATR spectroscopy, which shows a decrease in the 1741 cm^-1 band intensity for PHBHHx and PAF (after photooxidation) due to chain scission. However, no noticeable change is observed considering the same peak in the PAFB spectra. Furthermore, the evaluation of the hydroxyhexanoate (HHx) content in the different formulations is evaluated by ¹H NMR spectroscopy. The results show a slight decrease in HHx molar % after exposure to 216 h under accelerated photooxidation. Nevertheless, the decrease seems to level off after the addition of AF, particularly the treated ones. The overall findings highlight the beneficial effect of the incorporation of AF into the PHBHHx matrix, especially when treated with NaHCO₃ which confers a better photostability.

Introduction

Biopolyesters such as polyhydroxyalkanoates (PHAs) are promising biodegradable polymers for replacing conventional plastics, but their limited toughness and brittle fracture limit their industrial application. To improve these limitations, polymer additives are employed to enhance the mechanical properties. However, most of these are derived from non-renewable resources, and some of them have proven to be harmful to both the environment and human health. So, on these terms, the development of safe and sustainable alternatives is essential. Some of the most promising candidates are hyperbranched polymers (HBPs), characterized by a highly branched architecture and a high functional group density, making them candidates as biodegradable alternatives to common additives.

Results and discussion

This study focuses on the synthesis and functionalization of hyperbranched biopolyesters supported on microcrystalline cellulose (MCC) for use as an additive to improve the mechanical properties of poly(hydroxybutyrate-co-valerate) (PHBV). These polymers were synthesized via the polycondensation of 2,2-bis(hydroxymethyl)propionic acid (bis-MPA) in the presence of MCC, followed by grafting of linear polycaprolactone chains to enhance the flexibility. The results of thermal and structural characterization (FTIR, TGA, NMR, and DSC) confirm successful synthesis and functionalization; however, they show a higher proportion of linear over branched polymers.

The mechanical properties demonstrate a significant improvement in PHBV's toughness, including the emergence of post-yield fracture behaviour and increased plastic deformation. Moreover, a slight decrease in crystallinity was also observed. This communication will present the results obtained with the newly synthesized additives, confirming their potential as sustainable additives in plastic formulations.

Acknowledgments: This research was supported by project PID2021-128749OB-C32, funded by MCIN/AEI/10.13039/501100011033 and FEDER, UE. This work was also funded by the UBE Chair for Sustainable Plastics, from the Universitat Jaume I.

Graphene-based nanocomposites stabilized with polymers are emerging as promising materials for optoelectronic applications due to their tunable optical and structural properties. In this study, we investigate and compare the optical behavior of graphene oxide (GO), thermally reduced graphene oxide (RGO), and RGO films functionalized with poly(sodium 4-styrenesulfonate) (PSS). Thin films were deposited by dip-coating aqueous dispersions onto SiO₂/Si substrates and characterized using Variable Angle Spectroscopic Ellipsometry (VASE) in the 0.38–4.1 eV photon energy range. The dielectric response of GO and RGO films was modeled using three Lorentz oscillators, reflecting transitions associated with oxygenated functional groups and partial restoration of sp² hybridization. Conversely, the optical properties of PSS-RGO films are described by a single Lorentz oscillator at approximately 2.8 eV and a pole, indicating the formation of new electronic states likely arising from the improved ordering of sp² carbon domains during reduction in the presence of the polymer. Scanning Electron Microscopy (SEM) analysis reveals that PSS enhances the homogeneity and compactness of the films, preventing aggregation and promoting uniform coverage. These findings highlight the critical role of PSS as a functional matrix capable of modulating both the morphology and optical response of RGO, particularly in the extended near- and mid-infrared spectral range.