This is an editorial article. It has no abstract.

Polylactic acid (PLA) is one of the most widely used biopolymers, and it has demonstrated a huge potential for replacing some of the conventional plastics in certain application fields. However, due to a lack of other attributes such as antimicrobial properties and slow degradation rates, it is often blended with other polymers to impart these properties. Chitosan has desirable features including antimicrobial and antioxidant properties, biodegradability and biocompatibility, and environmental friendliness. Thus, it is widely blended with PLA to generate materials that can be applied in various fields. In recent years, PLA/chitosan blend composites and nanocomposites have been produced to develop sustainable and ecofriendly materials that can be suitable in active food packaging, water treatment, air filtration, and biomedical applications. This review provides an overview of the recent advancements in the development of PLA/chitosan blend composites and nanocomposites for various applications. The processing strategies, mechanical and thermal properties, together with utilization in biomedical, air filtration, water treatment, and packaging applications, are provided.

With the increasing use of e-mobility, the demand for high-quality materials to produce polymer gears is growing. Due to the tendency towards using natural materials and reducing carbon footprint, basalt fibers (BF) are tested as a substitute for glass fibers (GF). For this purpose, composites of polyamide 6 (PA6) with GF and BF, with and without compatibilizer and polytetrafluoroethylene (PTFE) are produced, tested, and properties compared. The mechanical, thermomechanical, thermal, and tribological properties of the composites, as well as the size of the fibers after the production of the composites and after injection molding, are determined. The compatibilizer improves the impact strength, while the glass fibers have a better reinforcing effect. The fibers increase crystallinity, but the effect is minimal. The thermal conductivity increases approximately the same for both fibers and is highest at composites that, in addition to 30% fibers, also contain PTFE. The tribological properties are comparable but slightly better for glass fibers. The fiber length is greatly reduced during the production of the composites and is around 200–300 μm in both cases. SEM imaging and mapping analysis show good dispersion of the fibers in the polymer and relatively poor compatibility with PA6.

Maleic anhydride (MA) is widely used to modify plastics and as a compatibilizer in recycling. This study examines the effect of varying MA concentrations on blends of polyoxymethylene (POM) and recycled polyvinyl butyral (rPVB) from automotive windshields. Morphological analysis showed that MA contents between 0.25 and 0.75 wt% led to smaller, more closely dispersed rPVB particles, indicating enhanced phase miscibility. Rheological and thermal analyses revealed up to a 47% increase in melt flow index at lower MA concentrations, and improved interfacial interactions and crystallinity at higher levels. The tensile modulus dropped by 10% at 0.25 wt% MA but increased with further additions; tensile strength and Shore D hardness remained unaffected. Impact strength improved by up to 65% with MA addition, mainly due to increased ductility and a morphology characterized by larger rPVB domains and shorter interparticle distances at low MA contents. The coefficient of friction decreased with rPVB but increased with MA, along with higher volume loss. Microscopic wear analysis confirmed that rPVB dispersion, influenced by MA, was key to transfer film formation and surface lubrication. Thus, MA optimization enables tailored mechanical and tribological properties in POM/rPVB blends.

Endowing vitrimers with latent heat storage property can broaden their applications in fields of energy storage and thermal management. In this study, we present the fabrication of transesterification dynamic bonded epoxy resin vitrimer-based form-stable phase change materials (V-PCMs). Poly(ethylene glycol) (PEG), serving as the latent heat storage component, was covalently anchored within the vitrimer network. The prepared V-PCMs were then comprehensively characterized. The results revealed that the obtained V-PCMs prototype exhibited a reversible latent heat storage and release property via the ordering/disordering transformation of the PEG segment, achieving a high latent heat storage capacity of 63.2 J/g. The V-PCMs also exhibited outstanding thermal stability with no thermal decomposition below 350 °C in air, along with excellent leakage resistance up to 150 °C. The flexibility of the PEG segments endowed the prepared V-PCMs with good tensile properties. Additionally, the materials could be efficiently reprocessed via hot pressing without significant property degradation. This work presents a novel strategy for developing crosslinked and reprocessable V-PCMs, and broadening their potential for sustainable thermal energy storage and management applications.

To reduce fuel consumption and extend flight time, the aerospace industry has focused on lightweight design. Achieving this without compromising structural integrity has been challenging. However, innovative additive manufacturing offers new opportunities for practical solutions. This study presents two methods: multi-material additive manufacturing (MMAM) and variable infill density additive manufacturing (VIDAM), aimed at reducing structural weight while maintaining mechanical performance. These methods were applied to a wing spar, a test geometry based on stress distribution principles from laminated beam mechanics. The structures produced with these new approaches showed improved mechanical responses compared to those made with traditional additive manufacturing techniques. A maximum increase of 91% in load-carrying capacity and a 34.8% increase in specific energy absorption were observed. scanning electron microscopy analysis revealed that layer bonding and material diffusion greatly influenced the mechanical performance. Although the study was conducted on small-scale models, the design concepts can be adapted to large-scale industrial applications that benefit from lightweight structures, such as the aerospace and automotive.

An epoxy-amine coating modified with 4-phenylazophenol (PAP) was developed on a steel substrate to promote self-healing capabilities. The self-healing mechanism is driven by light-induced trans–cis isomerization of the azobenzene moiety, enabling localized mobility of the polymer network and restoring surface integrity without thermal activation. The proposed epoxy–amine system combines thermoplastic-like processability with crosslinked mechanical stability, while its reversible physical crosslinks enable efficient recycling upon heating above the gel–liquid transition temperature. Furthermore, it was found that the modified coating enhanced corrosion resistance, UV stability, and durability. Electrochemical impedance spectroscopy (EIS) revealed higher low-frequency impedance values for PAP-epoxy, while Tafel analysis showed a significant reduction in corrosion current density, confirming enhanced anticorrosive performance. Compared to the unmodified epoxy system, PAP-epoxy exhibited reduced porosity and crack density, as well as more tortuous microcrack paths, thereby improving its barrier properties. The combined use of FTIR, TGA, and contact angle measurements demonstrated that PAP incorporation delayed the formation of oxidative degradation products and preserved thermal stability after prolonged UV exposure. The improved protective performance is attributed to the combined effects of microstructural refinement, reduced porosity, and UV-absorbing capability of PAP.

This study examines the performance of hybrid sandwich composites with a recycled aluminium foam (AlF) core and a recycled carbon-reinforced polymer skin layer. Three composite skin configurations were examined: (i) unidirectional (UD) carbon/epoxy sheets representing aligned virgin fibre reinforcement, (ii) randomly oriented recycled carbon fibre (rCF) mats consolidated by hand layup with epoxy, and (iii) randomly oriented rCF/epoxy sheets consolidated by hot pressing. The AlF core structure analysis revealed a low density and uniform open-cell structure ideal for lightweight cores. Comprehensive testing revealed significant performance differences between skin types and manufacturing methods, underscoring the critical role of processing – particularly hot pressing – in enhancing fibre compaction, matrix consolidation and interfacial bonding between the core and facesheets. Unidirectional carbon fibre skins achieved the highest flexural stiffness. In contrast, hot-pressed rCF mats provided the most balanced properties, combining high compression, damage resistance, and flexural strength, due to improved consolidation and reduced porosity in the face sheets. Thus, hybrid sandwich structures fabricated from recycled AlF core and rCF represent a viable, environmentally responsible alternative for aerospace, automotive, and protective applications requiring lightweight, high-strength, and damage-resistant materials.