In this work, a coating approach for obtaining flame retardant EVA (Ethylene - Vinyl Acetate) and EBA (Ethylene - Butyl Acrylate) copolymers-based materials is proposed. To this aim, firstly nanocomposite films of EVA and EBA were produced by cast extrusion, by using as nanofillers two types of layered double hydroxides (introduced at 5 wt.%), having the same chemical nature (Magnesium-Aluminium with intercalated oleate anions) but differing for the aspect ratio. The morphology of the nanocomposites films, as well as their thermal characteristics were preliminary assessed through rheological, thermal, and morphological analyses.

The films were then applied as coating to the corresponding neat copolymer substrate by compression molding, and the so-obtained samples were tested through cone calorimeter. Despite the small amount of nanofiller (0.5 wt.% considering the whole specimen), the application of the coating films significantly improved the Time to Ignition as compared to the pristine copolymers, while maintaining quite unchanged the shape of the HRR curves and the HRR peak values.

In all, the obtained results demonstrated the effectiveness of the coating approach, since it allows to concentrate the flame retardant action on the surface of a polymer system, where combustion specifically takes place; consequently, the required amount of flame retardant is minimized. This last has a beneficial effect on the final mechanical properties of the material, since the tensile characteristics of the bulk polymer are preserved. Furthermore, introducing such a small amount of flame retardant does not affect the future recyclability of the polymer, that can be treated as its pristine (non-flame retardant) counterpart.

Thermo-oxidation of natural fibers and their biocomposites has attracted considerable interest from researchers due to their wide-ranging applications in the fields of textile fabrics, construction materials, insulation, and automotive components. This makes the comprehension of their thermal degradation mechanisms, especially in the presence of oxygen, a matter of critical interest. Therefore, this study aims to investigate the effect of untreated and alkali-treated Agave Americana Fibers (AAF) on the kinetics of thermo-oxidation of PHBHHx biocomposites at 30 wt.% filler content. The experimental approach consists of subjecting neat polymer and its biocomposites to different heating rates, i.e., 5, 10, and 20 °C/min, under oxygen using thermogravimetric analysis, while applying the Coats–Redfern model-fitting method. The results reveal that TGA/DTG thermograms exhibit a single-step degradation process for PHBHHx, whereas the biocomposites show multi-step degradation phenomena attributed mainly to the cellulose and PHBHHx matrix. Kinetic analysis of the samples indicates that PHBHHx degrades via a diffusion-controlled mechanism, showing the best model fitting to the D2 Model. However, both untreated and treated biocomposite samples exhibit two degradation steps related to the base components, occurring via the P2 Model. This suggests that degradation is governed by the reactions occurring at the filler–matrix interfaces. Moreover, it has been demonstrated that alkali treatment of the fibers results in an increase of activation energy and onset temperature of the biocomposites (P-AAF-B) compared to those of untreated ones (P-AAF). Indeed, at a heating rate of 5°C/min, the activation energy values increase from nearly 178 and 537 KJ/mol for P-AAF relative to phases 1 and 2 to 426 and 623 KJ/mol for P-AAF-B, respectively. Moreover, at the same heating rate, the onset temperature increases from 221.70°C for P-AAF to 236.51°C for P-AAF-B. These results show that the addition of natural fibers, especially with surface treatment, is beneficial for enhancing the material's overall thermo-oxidative stability.

The development of cellulose-based nanomaterials with tailored surface properties is essential for advancing their integration into high-performance polymer nanocomposite systems. In this work, a mechanochemical strategy for the simultaneous production and surface functionalization of cellulose nanofibrils (CNFs) via wet ball milling, employing citric acid as a green crosslinking catalyst and N-alkanals (octanal, heptanal, and their binary mixture) as hydrophobizing agents, is presented. This one-pot process enables in situ surface modification while preserving the nanofibrillar structure of cellulose, providing a scalable, environmentally friendly method for the fabrication of functional nanofillers. Commercial microcrystalline cellulose was milled in an aqueous medium using high-energy planetary ball milling for an optimized time of 20 minutes. The resulting nanofibrils exhibited diameters below 100 nm and improved surface hydrophobicity, confirmed by increased static contact angle measurements. The modified CNFs also displayed stable dispersion behavior and were fabricated into thin films using vacuum-assisted self-assembly. Optical microscopy in reflected light mode revealed morphological differences linked to the specific N-alkanal used, indicating tunable surface texturing. This dual-function approach not only simplifies nanocellulose processing but also enables the engineering of interface-active nanomaterials suitable for reinforcing biodegradable polymer matrices. The resulting nanocellulose systems demonstrate strong potential for use in advanced nanocomposite applications, including sustainable packaging, coatings, and barrier materials.

The fine-structure characterization of polymer-based materials is one of the fastest-evolving areas in polymer science. Modern synchrotron light sources, equipped with high-flux microfocus optics and advanced detectors, offer powerful capabilities for investigating morphology, crystallinity, and nanoscale organization. Over the past two decades, synchrotron wide- and small-angle X-ray scattering (WAXS and SAXS) beamlines have become increasingly accessible and very useful for studying complex polymer systems.

This lecture presents three representative case studies. First, synchrotron WAXS and SAXS reveal structural features associated with enzyme immobilization on engineered polyamide microparticles, an essential step in designing efficient biocatalytic materials. Second, microbeam WAXS scans of polyamide powders (grain sizes 20–50 µm) produced by in situ polymerization effectively detect micron-scale inhomogeneities caused by embedded clays or metal particles, advancing the development of smart polymer-based enzyme carriers and microdevices. Finally, in polymer microfibrillar composites (MFCs), WAXS quantifies transcrystallinity and links it directly to mechanical performance, while advanced SAXS data analysis under controlled strain demonstrates reversible, strain-induced crystallization of the matrix polymer impossible to observe by other methods.

These examples show how synchrotron-based WAXS and SAXS have become essential tools for exploring nanostructure–property relationships and guiding the design of next-generation functional and sustainable polymer materials.

University of Minho, IPC – Institute for polymers and Composites, campus of Azurem, Guimarães 4800, Portugal

Macromolecular chemistry profoundly shaped the twentieth century through the remarkable development of new materialsi. The ongoing expansion of polymer science is driven by the constant demand for novel materials with unique properties that can enable nnovation.

Macromolecules, polymers, and block copolymers synthesized through living polymerization are particularly well-suited to meet this challenge due to their specific synthesis methods. Poly(vinyl ethers), which can only be polymerized via cationic methods, are known for their adhesive properties and high reactivity. When copolymerized with various vinyl monomers, different types of copolymers can be obtained, which can lead to improved properties.

Maghnite-H+, a true green ecocatalyst, has been the subject of numerous studies and applications involving various vinyl and heterocyclic monomers, including vinyl ethers. The primary objective of this work is to prepare block copolymers based on n-butyl vinyl ether using Maghnite-H+ as the ecocatalyst.

The first step of this study is the synthesis of poly(n-butyl vinyl ether) catalyzed by Maghnite-H+. The resulting polymer will be fully characterized using various analytical methods, including nuclear magnetic resonance (1H NMR), infrared (IR) spectroscopy, gel permeation chromatography (GPC), viscometry, and differential scanning calorimetry (DSC).

The poly(n-butyl vinyl ether) obtained will then be used as a macrocatalyst for the cationic polymerization of styrene (in both bulk and solution). This process aims to produce a PnBVE-b-PS block copolymer. The final product will be characterized using the previously mentioned methods, in addition to thermogravimetric analysis (TGA).

Additive manufacturing is rapidly expanding across industries but generates substantial polymer waste, particularly in Selective Laser Sintering (SLS), of which considerable quantities of unfused powder and faulty prints are typically discarded. The development of sustainable recycling pathways is therefore essential to minimize losses in material and adopt circular economy strategies in polymer processing.

In the present research, a recycling process is proposed for polyamide 12 (PA12) waste retrieved from SLS 3–Dimensional (3D) printer. Faulty parts and scrap material were collected, mechanically pulverized to an average particle size of ~2 mm for ease of handling, and subsequently reprocessed with a filament extrusion system. Homogeneous continuous filament with a diameter of 1.75 ± 0.05 mm was successfully produced and used as Fused Deposition Modeling (FDM) input material. Standardized tensile (ASTM D638) and compressive (ASTM D695) test samples were printed using FDM for determination of the mechanical properties of the recycled material.

Since the PA12 would undergo three (3) consecutive thermal cycles—initial sintering in SLS, re-melting in filament extrusion, and FDM printing—this study addresses the measurement of the effects of these thermal cycles on the structural integrity and mechanical behavior of the resultant FDM prints. In addition, Differential Scanning Calorimetry (DSC) and X-ray Diffraction (XRD) analyses were performed to investigate the semi-crystalline nature of PA12 and to evaluate possible changes in crystallinity after recycling. The outcomes of mechanical testing provide information on the retention of properties and compatibility of recycled PA12 as an input for FDM. The outcomes reveal the possibility of converting SLS scrap into FDM filament and demonstrate a feasible recycling process that not only minimizes polymer waste but also enhances material usage on multiple platforms of additive manufacturing.

Introduction
Smart polymers that change their structural conformation upon external stimuli have emerged as candidates for the formulation of multi-responsive nanocarriers. Development of such nanoplatforms is crucial for bypassing body resistance mechanisms in targeted drug or gene delivery applications.
Methods
In this work, reversible addition–fragmentation chain transfer (RAFT) polymerization led to the synthesis of a series of poly(2-(diisopropylamino)ethyl methacrylate-co-2-(dimethylamino)ethyl methacrylate-co-oligoethylene glycol methyl ether methacrylate), P(DIPAEMA-co-DMAEMA-co-OEGMA) terpolymers. Molecular characterization and self-assembly of polymers in various aqueous environments were carried out. The organic co-solvent protocol was followed for the drug loading of curcumin and quercetin in polymeric micelles. Physicochemical and photophysical properties of loaded nanoparticles were evaluated for a period of three weeks.
Results
P(DIPAEMA-co-DMAEMA-co-OEGMA) terpolymers were successfully synthesized, presenting different pH responses at pH values of 3, 7, and 10 in terms of mass and size of the self-assembled copolymer structures. Temperature-dependent dynamic light scattering (DLS) experiments revealed the thermoresponsive properties of the copolymer micellar aggregates. Curcumin and quercetin were efficiently encapsulated within the micelles, presenting colloidal stability as measured by DLS and ultraviolet–visible absorption spectroscopy (UV-Vis). Fluorescence experiments resulted in enhanced and red-shifted spectra for curcumin-loaded nanoparticles compared to pure curcumin. Quercetin-loaded ones also exhibited an enhancement in aggregation characteristics.
Conclusions
Multi-responsive and stable nanocarriers were fabricated, showcasing the applicability of P(DIPAEMA-co-DMAEMA-co-OEGMA) terpolymers in biomedicine.

Reactive extrusion is a common approach in industry to modify polymer structures and obtain and modify some of their properties. To increase the melt flow rate (MFR) in polypropylene (PP), adding peroxide during extrusion is a very common application. By adding peroxide, the molecular weight of PP is reduced by β-scission [1]. More advanced modification of the polymer structure can be performed by adding a radical initiator like a peroxide an coupling agent [2] or adding another polymer [3] or a combination of both to obtain graft polymers with the target polymer properties. This combination of different substances in conjunction with the radical process leads to variety of products and by-products, which makes the proper characterization of the various products quite challenging.

In this presentation, the characterization of two different polyolefins, LCB-PP and a HDPE-g-PP, obtained by reactive extrusion processes is presented.

To better understand the influence of chain architecture on the melt relaxation dynamics of LCB-PP, a combination of NMR spectroscopy and GPC-V-MALS was employed [2].

HDPE-g-iPP molecules were generated via reactive extrusion without the use of a coupling agent and were identified within the HDPE/iPP matrix using advanced hyphenated fractionation techniques, including cross-fractionation chromatography and two-dimensional HPLC in combination with spectroscopic techniques like IR. The effect of HDPE-g-iPP as a compatibilizer was confirmed by thermal, dynamic mechanical, and morphological analysis, as shifts in crystallization temperatures and glass transition temperatures and diffuse domain interfaces were observed [3].

[1] M. Rätsch, M. Arnold, E. Borsig, H. Bucka, N. Reichelt, Progress in Polymer Science, 2022, 22(7), 1195-1282.

[2] D. Gloger, D. Mileva, A. Albrecht, G. Hubner, R. Androsch, M. Gahleitner, Macromolecules, 2022, 55, 7, 2588-2608.

[3] D. Gloger, G. Hubner, A. Albrecht, L. Sobczak, J.-H. Arndt, D. Tranchida, W. H. Binder, M. Gahleitner, Appl. Polym. Mater., 2024, 6,17, 10824-10841.

This research focused on the extraction of chitin from an unconventional and underexploited biological source: the wings of the desert locust (Schistocerca gregaria). The primary objective was to optimize the conventional chemical extraction protocol to enhance both the yield and quality of the recovered chitin. To achieve this, an additional depigmentation step was introduced prior to the standard deproteinization phase. This modification proved to be highly effective. Notably, it reduced the number of chemical treatments required from seven baths in the classical method to only four, thus decreasing the overall processing time and chemical consumption, while simultaneously limiting the environmental footprint of the extraction process. The optimized protocol also led to substantial improvements in the extraction outcomes. The chitin yield increased markedly, rising from 10% to 29%, which reflects nearly a threefold improvement. In addition, the quality of the biopolymer was enhanced, as demonstrated by the increase in its molar mass, from 537,000 g/mol to 847,000 g/mol, suggesting better preservation of the polymer chains and reduced degradation during processing. These findings highlight the critical impact of both the biological origin and the protocol design on the final characteristics of chitin. This study underscores the necessity of tailoring extraction strategies to specific raw materials in order to obtain high-performance biopolymers suitable for advanced applications in biotechnology, agriculture, and materials science.

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.