Chitin and its derivative chitosan are two biopolymers that find numerous applications in various fields. Their industrial production, carried out mainly from marine crustaceans, does not meet the demand either in quantity or quality; hence, the exploration of new chitinous sources is necessary today. In this context, we explored the scorpion Buthus atlantis as a chitinous source in order to evaluate the quality and quantity of chitin it contains. The extraction, carried out with the objective of preserving as much of the native structure of chitin as possible, was carried out solely by deproteinization without resorting to other treatments. The chitins extracted from the different morphological parts of the scorpion were transformed into chitosans by N-deacetylation reactions under the conditions of the Kurita and Broussignac processes. The characterization of chitins and chitosans was carried out using the techniques of Scanning Electron Microscopy, Energy-Dispersive X-ray Spectroscopy, X-ray Diffraction, Fourier Transform Infrared Spectroscopy, Proton Nuclear Magnetic Resonance, Capillary Viscosimetry and Acid-Base Titration. All chitins, obtained with relatively high contents (16 to 24%), are pure and have an alpha structure. As for chitosans, they are prepared with low-value degrees of acetylation (8 to 15%) and molar masses that can vary from low to high (78000 g/mol to 270000 g/mol) depending on the application for which they are intended. These results show that the scorpion Buthus atlantis is a potential source for the production of biopolymers.

The automotive industry aims to develop high-quality engineering materials that ensure safety and optimal performance under various conditions. A critical application example is automotive headlights, whose durability and performance can be compromised by environmental and mechanical factors. To address these challenges, an alternative is proposed through the development of interpenetrating polymer networks (IPNs) of poly(methyl methacrylate) (PMMA) and polyurethane (PU), in PMMA/PU ratios of 50/50 and 80/20 [1], reinforced with 0.1% by weight of crystalline nanocellulose (CNC) obtained from disposable cups. Using experimental techniques such as Fourier-transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD), it was determined that the fiber processing for CNC extraction does not modify or degrade its main functional groups [2], and allows for a crystallinity percentage of 52.51% [3]. Additionally, to identify the characteristic morphologies of each polymer, confocal laser scanning microscopy (CLSM) analysis was employed, enabling the visualization of cellulose particles present. The observed fiber properties are also described, along with an analysis of cellulose dispersion within the polymer matrix and its fluorescence emission. Finally, durability is studied through tensile and compression mechanical tests, conducted before and after exposure to weathering. The results indicate less mechanical damage when crystalline cellulose is added to the PMMA/PU with a 50/50 ratio compared to a 80/20 ratio.

Hydrogels are crosslinked hydrophilic polymer networks that are capable of absorbing high levels of water without dissolving. Among naturally derived systems, alginate-based hydrogels are particularly attractive due to their biodegradability, non-toxicity, and mild gelation in the presence of calcium ions. In this study, we report the synthesis and thermal characterisation of sodium alginate hydrogels crosslinked with varying CaCl₂ concentrations and physically loaded with melatonin, a bioactive indoleamine with antioxidant and plant-growth regulating properties. The aim was to investigate the thermal behavior of the systems and analyze the effect of melatonin incorporation on the polymer matrix. A combination of Thermogravimetric Analysis (TGA), Differential Scanning Calorimetry (DSC), and Temperature-Modulated DSC (TMDSC) was used to assess water content, thermal transitions, and structural interactions. TGA indicated a gradual reduction in water retention with increasing CaCl₂ concentration, reflecting the formation of denser, more tightly crosslinked hydrogel networks. Following a seven-day swelling period in deionized water, the observed mass loss below 150 °C was attributed to the evaporation of both free and bound water. Differential Scanning Calorimetry (DSC) and Temperature-Modulated DSC (TMDSC) offered further insight into the structural integrity of the hydrogels and the interactions between melatonin and the polymer matrix. The presence of melatonin led to more distinct and slightly shifted endothermic peaks, potentially linked to the melting of crystalline melatonin or weak, non-covalent interactions with alginate chains. TMDSC enabled the separation of reversing and non-reversing events, highlighting possible reorganization of the matrix upon melatonin inclusion. This supports the hypothesis of partial structural rearrangement of the hydrogel network upon melatonin incorporation. In some cases, the typical melting peak of crystalline melatonin was absent or shifted, suggesting a degree of amorphous dispersion within the hydrogel network.

The use of recycled polymers and agricultural waste could be an important tool to reduce the environment impact of plastic manufacts and to valorize the agricultural waste. In this work recycled PP and hazelnuts shells were used in order to produce green composites to be applied for the production of fittings for irrigation systems. In order to improve the poor adhesion between matrix and filler an adhesion promoter was also used. The adhesion improves in particular for the composites with the recycled polymer probably because of the presence of polar groups in the recycled sample. The rheological properties clearly indicate that the composites show a processability similar to that of the pure polypropylene and this feature has been corroborated by industrial preliminary injection molded tests where the fitting was easily produced. The deformability of the composites is reduced with respect to the pure matrix although slightly improved by the presence of the adhesion promoter. The composite with RPP as matrix and 5% of hazelnut shells with and without adhesion promoter were also used to produce a fitting by injection molding and all the fittings were resistant to the water pressure of 3.50 bar according to the internal test used by the company

Introduction

In the present research work, wood-based composites were prepared by adding different poplar powders within a soybean-oil-based resin, choosing liquid crystal display (LCD) as vat photopolymerization (VP) among the additive manufacturing (AM) technologies used for polymer processing. The aim was to combine the advantages of AM with the valorization of poplar wood powder waste from the plywood industry to obtain innovative and more sustainable composite materials as alternatives to classic fossil-based materials for interior design applications.

Materials and Methods

Several photocurable formulations were prepared using an acrylate epoxidized soybean oil (AESO) resin as the polymer matrix and isobornyl methacrylate (IBOMA) as reactive diluent, in the presence of 2 wt.% of phenyl bis(2,4,6-trimethylbenzoyl), with phosphine oxide (BAPO) as the photoinitiator. Bio-based composites were obtained by adding 3 wt.% of different wood poplar powders (P_I and P_IV), two by-products from plywood panel production, to the AESO formulations and 3D printing different parts in an LCD 3D printer.

Results and Discussion

A comprehensive characterization of the composites fabricated by VP was carried out. Rheological, thermal, morphological, and mechanical measurements were performed to investigate the final properties of the 3D-printed wood-based composites. Several 3D-printed components were fabricated, showing different levels of detail and complexity. The specimens showed enhanced final properties in terms of elastic modulus, glass transition temperature, and storage modulus due to the reinforcing effect induced by the presence of the fillers.

Conclusions

This research demonstrates that bio-based components can be successfully 3D-printed via LCD, including objects with potential application in interior design, such as joints and connections, highlighting the material’s suitability to realize customized and more sustainable elements for design-oriented applications.

Introduction

Uncontrolled hemorrhage is a major cause of death in civilian and military settings (30 and 80%, respectively), often complicated by infection. This underscores the critical need for rapid, effective hemostatic materials. Natural polysaccharides are promising for this purpose. This study aimed to synthesize a novel powdered hemostatic material using a scalable spray-drying technique for rapid hemorrhage control, leveraging the polyelectrolyte properties of chitosan (CHI) and carboxymethylcellulose (CMC).

Methods

Polyelectrolyte complexes (PECs) were formed by dropwise mixing of CHI (1.5% w/v) and CMC solutions (0.5, 1, and 1.5% w/v). These PECs were then spray-dried (inlet temperature 160°C, outlet temperature 80°C, aspirator 70°C) to yield powdered microgels (1.5Q/1.5CMC; 1.5Q/1.0CMC; and 1.5Q/0.5CMC). The resulting microgels were evaluated for their morphological, physical, thermal, swelling, and hemostatic properties.

Results

ATR-FTIR spectra confirmed electrostatic interactions between amino and carboxyl groups of CHI and CMC in all microgels. The SEM technique revealed an irregular spherical morphology with an average size of 2–3 µm for all microgels. The gel fraction test (GF) showed that 1.5Q/1.5CMC samples had higher crosslinking between CHI and CMC (64.2±1.7%) compared to 1.5Q/1.0CMC (49.9±2.5%) and 1.5Q/0.5CMC (42.9±3.8%). Additionally, 1.5Q/1.5CMC microgels exhibited higher swelling percentages (up to 900%) in PBS solution (pH 7.4) than 1.5Q/1.0CMC and 1.5Q/0.5CMC (up to 600%). TGA analysis indicated similar thermal behavior across all microgels, with three or four degradation stages and a degradation temperature (Tp) around 240°C. Hemolysis testing (ASTM-F756-00) showed all microgels had a hemolysis percentage below 5%, confirming their hemocompatibility. Furthermore, all microgels reduced the coagulation time by 20% in comparison with whole blood without microgels.

Conclusions

Three powdered microgels were successfully obtained using CHI and CMC via spray drying. Among them, 1.5Q/1.5CMC microgels demonstrated superior physicochemical properties, including higher gel fraction and swelling percentages, making them particularly promising for use as hemostatic materials.

Noise pollution provoked by vehicles is a growing problem that negatively impacts health. For this reason, it is necessary to explore the possibility of improving sound insulation of some parts of the vehicle, such as commercial automotive paints or panels. This work deals with studying the incorporation of natural fibers into an acrylic commercial paint. Dispersions of microcrystalline cellulose (C) and nanocellulose (NC), extracted from commercial cellulose, type Iα, obtained by chemical methods (hydrogen peroxide and sodium hydroxide) and acid hydrolysis (sulfuric acid), were prepared at different concentrations (0.1, 1, 3, and 5 wt%). These formulations were applied onto 3003 aluminum substrates and characterized by Raman spectroscopy, X-ray diffraction (XRD), and optical microscopy. Moisture resistance and sound absorption capacity were also evaluated. Raman and XRD analyses confirmed the presence of cellulose and paint components such as titanium dioxide (TiO₂) in anatase and rutile phases. On the other hand, optical microscopy showed that NC presented better dispersion and less agglomerates than C. In acoustic performance, the results showed that the addition of C at 5 wt% led to the best noise attenuation compared to NC. C displayed values c.a. 2.4 dB (3.15%) in the minimum value and 1.7 dB (2.05%) in the maximum value compared to the paint. However, the incorporation of both materials increased moisture absorption. In conclusion, the addition of microcrystalline cellulose to automotive paints may be promising for automotive sound insulation.

Environmental pollution is one of the most challenging problems worldwide, and water is one of the most vulnerable environmental matrices, being an essential resource for life. The exponential increase in industrial manufacturing processes, technological development, urbanization, natural climatic events, and agricultural practices, among others, have generated environmental exposure to numerous chemical compounds that cause the contamination of aqueous matrices. This challenge has led to the development of hybrid nanocomposite biosorbents as an innovative strategy for the aqueous removal of relevant pollutants. These nanocomposites, created from biopolymeric hydrogels and nanoclays, are an effective, sustainable, and scalable strategy for the removal of these pollutants. Our work seeks to provide concrete solutions to the complex problems of water pollution, using the potential of nanocomposite biosorbents. The present work aims to develop materials with biosorbent capacities, based on natural and innocuous raw materials such as the biopolymers chitosan (Q) and sodium alginate (Alg), as well as natural and organomodified bentonite (B) and organomodified (OB) nanoclays. These starting materials are abundant, inexpensive, and environmentally friendly. Nanocomposite biosorbent hydrogels of Q/OB, Alg/B, and Alg/OB were developed using simple and low-cost techniques. The biosorbents were physicochemically and morphologically characterized. These tests revealed internal structures with large porosity, favorable for the diffusion and adsorption of the pollutant. Preliminary atrazine, ciprofloxacin, and arsenic removal tests were performed under batch conditions. The results showed promising biosorptions for all the pollutants studied. These results show the potential of the developed biohydrogels as efficient systems for the aqueous remediation of contaminants of relevance to mitigate a real problem of global concern.

Cancer remains one of the leading causes of mortality worldwide. Despite the availability of various treatments, most of them cause adverse side effects that affect the health and well-being of patients. This has driven the search for innovative, less invasive, and more body-friendly therapies, such as hyperthermia, which involves raising the temperature of tumors to between 40 and 45°C to induce cellular damage without compromising healthy tissue. With the goal of developing a localized treatment that targets tumor tissue without affecting surrounding tissue, the use of magnetite (Fe₃O₄) nanoparticles has been proposed. These nanoparticles have generated significant interest due to their ability to generate heat when exposed to an alternating magnetic field. However, their stability in biological systems represents a challenge; therefore, the present project proposes the functionalization of pectin hydrogels with magnetite nanoparticles, taking advantage of the biocompatibility and encapsulation capacity of pectin together with the magnetic properties of magnetite. The hydrogel was synthesized in situ by mixing a pectin solution with iron salt precursors and stabilizing agents (FeSO₄, urea, and glycine). The pH was adjusted to 9-11 to favor magnetite formation over the other oxide phases, using NaOH and NaHCO₃. Subsequently, the hydrogel was crosslinked with CaCl₂, and once the polymeric three-dimensional network was stabilized, it was analyzed using various characterization techniques. Among these techniques, Fourier Transform Infrared Spectroscopy was employed to assess chemical structural changes resulting from the synthesis process. The analysis confirmed the crosslinking of pectin chains by CaCl₂ addition and the interaction of magnetite nanoparticles with the polymer matrix. Additionally, X-Ray Powder Diffraction analysis confirmed the formation of pure magnetite, distinguishing it from the other iron oxide phases. The preliminary results suggest that pectin–magnetite hydrogels may offer a promising platform for magnetic field response in biomedical applications.

The present work proposes the use of metal hydroxides, specifically aluminium and magnesium hydroxides, as halogen-free flame-retardant additives in polymer matrices. The present study focuses on comparing their performance in polyolefin-based polymers and bio-polymer composite formulations. This approach is motivated by sustainability considerations and the growing market demand for environmentally friendly flame-retardant materials.

The incorporation of metal hydroxides occurred within two different composite materials: firstly, an EVA/LLDPE blend and secondly, a PBS matrix. Two types of metal hydroxide were evaluated for use in the formulation of flame-retardant composites (FRCs): precipitated aluminium hydroxide (p-ATH) and naturally milled magnesium hydroxide (nm-MDH). The p-ATH displays a crystalline composition, whereas nm-MDH manifests a brucite crystalline form. The presence of this dolomite phase is advantageous, as it decomposes at higher temperatures than the metal hydroxides and releases inert gases such as carbon dioxide, thereby enhancing flame resistance.

The characterisation of both metal hydroxides was accomplished through a multifaceted approach encompassing X-ray powder diffraction (XRD), thermogravimetric analysis (TGA), meticulous morphological observation, and a comprehensive application of spectroscopic methodologies. It has been established that upon exposure to heat or flame, the metal hydroxides undergo endothermic decomposition, forming metal oxides and releasing water molecules. This reaction has been shown to result in an intumescent effect.

Through our investigation, we found that all of the examined FRCs displayed remarkable flame retardancy, fire resistance, and thermal stability—that is to say, resistance to static heat. These results underscore the potential of these metal hydroxides as effective halogen-free flame-retardant additives. Furthermore, while to a lesser extent, the presence of hydroxides of metals was found to reduce the accumulation of groups containing carbonyl and hydroxyl functionality during UVB weathering exposure. This finding suggests a protective effect on the polymer matrix.