Chemistry and Materials Science

Abstract: A novel multifunctional isocyanate curing agent, denoted as TCI, was facilely synthesized via a one-step reaction involving 1,3,5-tris(2-hydroxyethyl)cyanuric acid and hexamethylene diisocyanate. The structural design of TCI incorporates a rigid triazine ring core and three additional urethane linkages, enabling the construction of high-performance crosslinked networks within glycidyl azide polymer (GAP)-based energetic elastomers. By systematically comparing TCI with the commercially available curing agent N100, the structure–property relationships were elucidated through a combination of curing kinetics, spectroscopic characterization, mechanical testing, and thermal analysis. TCI exhibits superior reactivity toward GAP, effectively compensating for the low reactivity of secondary hydroxyl groups. Structural characterization via XRD, SAXS, and FTIR demonstrated that TCI facilitates the formation of dense and stable hydrogen-bonding networks, which reduce the intermolecular chain spacing (0.424 nm for TCI–GAP vs. 0.436 nm for N100–GAP) and optimize the microphase separation behavior of the elastomer networks.Mechanical testing demonstrated that the tensile strength and elongation at break of TCI–GAP reach 1.74 MPa and 297.7%, respectively, representing increases of 95.5% and 163% over N100–GAP (0.85 MPa and 105.8%). Morphological analysis confirmed the presence of uniformly distributed crosslinking junctions and ductile fracture features in TCI–GAP, which are responsible for the improved load-bearing capacity and energy dissipation efficiency. Dynamic hydrogen-bonding interactions were identified as the key mechanism governing the mechanical and thermal performance of TCI-GAP. DMA and LF-NMR results indicated that TCI–GAP possesses higher storage modulus and more restricted segmental motion, leading to excellent thermomechanical stability. The novel TCI curing agent offers a facile and effective approach to simultaneously improve the mechanical strength, toughness, and thermal stability of GAP-based networks, showing great promise for applications in advanced solid propellants and energetic materials.

Abstract: Phenolphthalein poly (aryl ether ketone) (PEK-C) is highly compatible with the epoxy resin, which is applied in epoxy resin-based composites to improve its strength. Solu-tion spinning and electrospinning techniques are often used to produce the PEK-C fi-bers, but these techniques are polluting the environment and are not productive. To address the above challenges, melt spinning may be employed but since the high de-gree of molecular chain entanglement and poor melt fluidity of PEK-C, melt spinning remains difficult. Herein, this study presents a continuous melt spinning of PEK-C fi-bers through rheology modulation and melt strength enhancement. A series of PEK-C samples with different molecular weights were prepared by adjusting the molar ratio of monomers. The influence of molecular weights on rheological properties was inves-tigated by capillary rheology tests. The PEK-C with molecular weight (2.01×104 g/mol) was chosen and the optimal spinning temperature was determined to be 370 °C. The as-polymerized PEK-C powder was compounded into pellets, subsequently, the PEK-C pellets with the enhanced melt strength were continuously processed into fiber by melt spinning. The obtained PEK-C fibers possess high tensile strength 0.56 cN/dtex and breaking strength 1.06 cN/dtex, respectively. The mechanical properties and molecular chain orientation of PEK-C fibers were also optimized by spinning process parameters. This work presents continuous melt spinning of PEK-C fibers by rheology modulation and melt strength enhancement which resolve the environmental and low productive issues.

Abstract: Optical spectroscopy provides several useful information about polymeric ultrathin films by combining interferometric and optical absorption data contained in the UV-Vis-NIR spectra. In particular, the UV-Vis-NIR spectrum of an ultrathin polymeric film contains information about the film thickness, structural disorder, bandgap energy, type of electron transition model (direct/indirect, allowed/forbidden), cutoff wavelength (i.e., the opaque/transparent switching wavelength), etc. Here, these properties have been determined for a model semi-crystalline polymer (polyethylene terephthalate, PET) in form of ultrathin film before and after a mild mechanical deformation treatment (manual stretching). It has been found that E_U and E_g parameters are not strictly depending on mechanical deformation due to their main dependence on chemical composition/constitution of the polymer; consequently E_g can be used for polymer identification in the case it has a dielectric nature.

Abstract: This research study will provide methodical scientific explanations for color-mismatches in compounded plastics and identify the dispersion characteristics of the pigments used. Related issues will also be addressed to develop better formulations that enhance color coordination, color stability, and the uniformity of compounded plastic materials, while minimizing waste. In previous research, the focus was on transparent grades, whereas in this paper, opaque polycarbonate (PC) grades were the focus, with data collected through data mining of archived records from an industrial plant. Also, data mining methods were used to identify relationships between particular processing factors and color variations. In addition, Grade B was considered due to its identical pigmentation but different polycarbonate resin percentages, with R1/R2 equal to 90/10% which yields 101 associated color adjustments in total. The number of lots without adjustment is 60, and 41 with adjustment. Interactions among three parameters of the processing (PPs) in order to maintain the same color mixture under various conditions were studied using both experimental and numerical methods. Using General Trends (GT) methods, PPs were controlled at five different levels independently, while keeping all other variables constant. Moreover, the impact effects of PPs on color output and the effect of tristimulus color (l*, a*,b*, L*, and dE*) were also analyzed. From the above and from an engineering perspective, it is crucial to understand how these parameters affect color consistency. A comparison, using a spectrophotometer, between standard target values (CIE L* - 63.36, a* - -0.34, b* - 0.20) and the measured color values was conducted, identifying the significant PPs that contribute to the minimum color deviation. The distribution of the particle (PSD) size (2 µm) is dominated by small particles at all temperatures (T). Similar peak percentages (60–63%) are shown when Temp reaches 230 °C and 280 °C, and slightly lower percentages (60%) when Temp reaches 255 °C. This suggests is rising in temperature (from 230 to 280 degrees Celsius) slightly shifts the distribution toward smaller particles, but a more balanced mix of small and medium particles appears at 255°C, suggesting Temp, which influences particle breakage and agglomeration behavior. When most particles stay in the range of 1-3 µm for all Temps, consistent fine dispersion is demonstrated. Using Design of Experiments (DOE), impending research will expand GT analysis to include interactions between several parameters. Furthermore, processing temperature will be the subject of an ANOVA to determine its statistical significance, with the results being confirmed at a confidence level of p < 0.05. In order to back up the creation of prediction models for industrial-scale applications, the study will also evaluate the diagnostic procedure's robustness across different polymer grades and colorants. The improved color matching performance for opaque grades was a direct outcome of the high-quality mixing that occurred during the polycarbonate compounding process, which also minimized color streaking and guaranteed uniform distribution of pigments. By means of a particle size analyzer on the Microtrac S3500, it examined the distribution of primary particle sizes for four different colors. Black channel (13-20 µm), red iron oxide (0.8-1.6 µm), titanium dioxide (1.7-8.0 µm), and organic yellow (0.8-1.8 µm)were the ranges of measurements. Improved dispersion and less aggregation were achieved by employing increased ultrasonic power and duration. Similar to the reference pigment, the main pigment displays ranging from 1 to 2 µm in size. Mean particle size and particle count are positively correlated; rising temperatures result in smaller pigments and more particles, which affect colour response. Particle sizes were nearly identical when PSA and SEM were compared to PSD. The improved color matching performance for opaque grades was a direct outcome of the high-quality mixing that occurred during the polycarbonate compounding process, which also minimized color streaking and guaranteed uniform pigment dispersion.To finish, the influence of processing temperature on viscosity, dispersion of pigment size at three different temperatures, and color superiority was investigated by analyzing the effects of viscosity, Digital Optical Microscopy (DOM),Scanning Electron Microscopy(SEM) ,and pigment size distribution(PSA) at various processing levels. The samples were characterized for viscosity, DOM, and Particle size distribution at (230°C, 255°C, and 280 °C) temperatures. The overall mixing of PC compounding ingredients ensures uniform pigment dispersion, minimizes color-mismatching and results in minimal color difference (dE*), which improves color-matching significantly.

Abstract: Sustainable soft sensors are increasingly integral to wearable systems and human–machine interfaces; however, many current implementations depend on petroleum-derived elastomers and complex microfabrication. In this context, biopolymer-based conductive composites provide a complementary pathway toward low-cost, water-based processing and more environmentally responsible sensing architectures. This work reports a proof-of-concept pressure sensor based on a starch-derived biopolymer film doped with electrographite powder. The sensing layer, fabricated by spin coating, is integrated into an aluminum/biopolymer/aluminum sandwich configuration supported on an acetate substrate. Electrical resistance measurements under compressive loading (10–1000 g applied over 5.06 cm²; 0.2–20 kPa) show that the neat starch film remains electrically insulating, whereas the electrographite-doped film exhibits a clear piezoresistive response, with resistance decreasing as load increases. Compared with graphite-doped films, electrographite provides a more consistent response and a low hysteresis (<5%) in representative loading–unloading curves under the reported protocol. These results support the feasibility of using a biobased, starch-based sensing layer for low-cost flexible sensing concepts.

Abstract: Monodisperse porous polymer spheres are functional materials with attractive properties such as high cohesive strength, strong adsorptivity, and a high degree of surface functionalization due to their large specific surface area. They are widely used in various fields, including biomedicine, instrumental analytics as stationary phases in HPLC columns, and sensor technology. In this work, the formation mechanism of porous poly(glycidyl methacrylate-co-ethylene dimethacrylate) (p(GMA-co-EDMA)) particles was investigated in a time-resolved experiment using scanning electron microscopy (SEM) and two-dimensional confocal Raman spectroscopy. Data analysis revealed that the particles are formed via rapidly reacting anisotropic Janus-like intermediates that assemble into large agglomerates of different morphologies. Spectral unmixing of the Raman data enabled to determine relative concentration changes of the reactants over time. This study uncovers a pool of previously unknown anisotropic particle species that offer new opportunities for subsequent functionalization and material design.

Abstract: Oleanolic acid is a naturally occurring pentacyclic triterpenoid with broad preclinical interest in inflammation, oxidative stress, liver injury, metabolic disorders, cancer-related models, skin disease, and wound repair. Its further development, however, is constrained by poor aqueous solubility, low and variable bioavailability, limited barrier transport, crystallinity, and strong dependence of biological response on the formulation used. These properties make oleanolic acid a useful example of a hydrophobic natural com-pound whose pharmacological performance is inseparable from delivery design. This review examines polymeric and polymer-assisted nanocarriers developed for oleanolic acid delivery. The systems discussed include biodegradable PLA/PLGA na-noparticles, PEGylated polymeric nanoparticles, polymeric micelles, hyaluron-ic-acid-based nanoprodrugs, polymer-assisted lipid systems, hydrogels, nanogels, polymeric fiber membranes, local depots, and microneedle-compatible platforms. Rather than treating these carriers only as solubility enhancers, the review evaluates how polymer composition, carrier architecture, drug physical state, release behavior, and route of administration affect oleanolic acid exposure. Particular attention is given to controlled release, local retention, disease-oriented de-livery, and critical quality attributes such as particle size, loading, encapsulation effi-ciency, solid-state form, stability, residual solvent, sterility, and batch-to-batch repro-ducibility. The review argues that the most realistic near-term opportunities for polymeric oleanolic acid systems may lie in local and tissue-targeted applications, including in-flammatory skin disease, wound healing, dermal delivery, and osteoarthritis, where sustained exposure at the target site may be more relevant than systemic bioavailability. Future progress will depend less on demonstrating that oleanolic acid can be loaded into another carrier and more on showing that each formulation provides reproducible, safe, and route-appropriate drug exposure.

Abstract: Porous polymer nanocomposites incorporating metal oxide nanoparticles (SiO₂, ZrO₂, and TiO₂) were synthesized via the aza–Michael addition reaction of ethyleneamines with poly(ethylene glycol) diacrylate (PEGDA) under polymerization-induced phase separation conditions. The resulting nanocomposites exhibited interconnected particulate morphologies with particle diameters ranging from less than 0.5 to 5.0 μm. Increasing the nanoparticle content led to a significant reduction in particle size, indicating that the nanoparticles influenced the phase-separation process and the development of the porous structure. Energy-dispersive X-ray spectroscopy confirmed the homogeneous distribution of nanoparticles throughout the polymer matrix. The refinement of the porous morphology increased the bulk density and consequently enhanced the Young’s modulus of the nanocomposites. In addition, porous nanocomposites containing SiO₂ nanoparticles exhibited distinct coloration when immersed in toluene owing to the Christiansen filter effect. The transmission wavelength shifted toward longer wavelengths with increasing SiO₂ content, which was attributed to an increase in the effective refractive index of the porous nanocomposites. These results demonstrate that incorporation of metal oxide nanoparticles provides an effective strategy for controlling the morphology, mechanical properties, and optical functionality of porous polymer nanocomposites.

Abstract: Triazole-containing poly(ester amide)s were synthesized by a one-pot Cu(I)-catalyzed click step-growth polymerization using adipate-based dipropargyl esters and in situ generated diazide monomers derived from aliphatic diamines. Two polymers differing in the length of the polymethylene segment of the diamine unit (six and ten methylene groups) were ob-tained with yields close to 50% and molecular weights typical of step-growth polymeriza-tions. FTIR and NMR analyses confirmed the formation of the expected polymer structures incorporating 1,2,3-triazole rings. Despite the complexity of the repeat unit, both polymers were semicrystalline and exhibit-ed high glass transition and melting temperatures, reflecting strong intermolecular inter-actions associated with amide and triazole groups. Thermal stability and processability were strongly dependent on the diamine spacer length, with the longer polymethylene segment allowing melt processing without significant degradation. The polymers displayed good in vitro cytocompatibility and were suitable for the prepara-tion of stable nanoparticles with narrow size distributions and negative zeta potentials around −30 mV. Degradation studies revealed low hydrolytic and enzymatic degradability under physiological conditions, in contrast to previously reported polyester analogues. These results highlight the potential of triazole-based poly(ester amide)s as biocompatible materials with potential interest for biomedical applications.

Abstract: This study investigates the full production and characterisation chain of an eco-innovative polymer composite — designated DMP (Downcycled Mixed Plastic) — manufactured from hard-to-recycle, contaminated plastic waste streams via a continuous single-screw extrusion process. The composite, comprising approximately 60–70% polyethylene (PE), 20–30% polypropylene (PP), and 5–10% other polymers (ABS, PET, PS) with 2% impurities, was characterised by differential scanning calorimetry (DSC), density measurement, tensile testing (SR EN ISO 527-1:2020 / SR EN ISO 527-2:2012), impact resistance, bending, compressive strength, wear resistance (Bohme method), water absorption, thermal resistance, and microbiological analysis, performed by accredited Romanian laboratories. The single-screw extruder (D = 150 mm, L/D = 17.3, 30 rpm, barrel 200–220 °C, die 80–120 °C, pressure 60–120 MPa) converts unsorted, unwashed mixed polyolefin waste into dimensionally stable construction profiles without compatibilisers or virgin polymer input. DSC confirmed PE (softening 50–114 °C), PP homopolymer (melt 200–212 °C, crystallisation ~230 °C), and PP copolymer (melt 219–235 °C) fractions. Tensile strength was 9.22 ± 0.38 MPa (elongation 112.8 ± 8.4%, n = 5, unexposed); after 300 h UV weathering: 10.28 ± 0.42 MPa (76.6 ± 5.8%); after 50 freeze–thaw cycles: 9.55 ± 0.35 MPa (57.3 ± 4.9%). Compressive strength: 14.5 ± 0.9 MPa; static failure load: 29.03 ± 1.2 kN; thermal conductivity: 0.162 ± 0.008 W/m·K. All values meet applicable standard reference thresholds. Results confirm DMP composites as technically viable for non-structural load-bearing construction applications while diverting non-recyclable waste from landfill and incineration.

Abstract: This preprint has been withdrawn at the request of the authors due to the lack of consent from all authors prior to posting.

Abstract: The present research work compares graphene/PMMA-based nanocomposites prepared with various modified graphene nanoparticles to develop polymer-based nanocomposites with enhanced electromagnetic interference (EMI) shielding efficiency. A metal-decorated graphene (G/Ag) nanostructure was compared with an irradiated hybrid carbon nanostructure comprising graphene and multi-walled carbon nanotubes (G/CNTs). Three representative composites with varying filler loadings (15–20 wt%), thicknesses (0.208–0.48 mm), and an e-beam irradiation dose of 50 kGy were systematically characterized using SEM, FTIR, TGA/DSC, and vector network analyzer (VNA) measurements in the S-band (2.65–3.90 GHz). The effects of these different modifications (metal decoration or e-beam irradiation) on conductive network construction, interface engineering, and the resulting porous or layered structures on EMI shielding performance are discussed. All tested composites exhibited a strongly absorption-dominant behavior. Better EMI shielding effectiveness (SE) results were obtained for the irradiated PMMA/АМ1 (50 kGy) sample (d = 0.48 mm) and the PMMA/AH50 sample (d = 0.28 mm), reaching up to 11–13 dB compared to the metal-decorated PMMA/G/Ag nanocomposite. The obtained results confirmed that by increasing the sample thickness and the G/CNT hybrid content, the EMI shielding performance was significantly enhanced due to a greater absorption volume and denser conductive networks. This demonstrates the potential of irradiated graphene/CNT–PMMA nanocomposites as lightweight EMI shielding materials for various electronic and biomedical devices.

Abstract: In recent decades, due to the rapid development and application of wireless communication, flexible electronics, and smart devices, electromagnetic interference (EMI) and radiation pollution have been intensified, creating an urgent demand for efficient EMI shielding materials. Carbon nanostructures such as graphene and carbon nanotubes are considered promising candidates due to their excellent properties, such as high electrical conductivity, low density, large specific surface area, and flexibility. This work reports our recent results in the design and testing of polymer nanocomposites with irradiated hybrid carbon nanostructure (graphene/multi-walled carbon nanotubes) used as EMI shielding materials. Five representative composites with varying filler loadings (AH of 15% and AM1 of 20 wt%), thicknesses (0.208–0.48 mm), and e-beam irradiation doses (from 50 to 400 kGy) were systematically characterized using SEM, FTIR, TGA/DSC, and vector network analyzer (VNA) measurements in the S-band (2.65–3.90 GHz). The effects of different e-beam irradiation doses and hybrid carbon content on conductive network construction, interface engineering, and porous or layered structures on EMI shielding performance are discussed. Experimental results show that all studied composites exhibited strong absorption-dominant behavior (SEA), while the multiple reflection component (SEM) was found to be negligible. Both filler loading and sample thickness significantly enhanced shielding performance, with a pronounced synergistic interaction observed between these parameters. A quadratic Response Surface Methodology (RSM) model was developed to correlate SET with thickness and filler content, yielding high predictive accuracy (R2 > 0.99). The model enables efficient optimization of composite design for targeted shielding levels.

Abstract: Additive Manufacturing (AM) process parameters significantly influence the thermal, mechanical, and surface roughness properties of printed parts. While experimental characterization is highly accurate, it is often excessively time-consuming and costly, hindering the development of scalable predictive models. This study adopts a Materials Informatics approach to curate a multi-sourced benchmarking dataset comprising 543 entries for ABS, PLA, and TPU filaments, integrating data from web-scraping (WSDS), literature (LDDS), and manufacturer technical datasheets (MTDS). Data cleaning included outlier detection via Tukey’s fences and the evaluation of imputation strategies, with K-Nearest Neighbors (KNN) consistently outperforming simple mean/median methods. We evaluated three regression models, Random Forest (RF), Ridge Regression (RR), and Support Vector Regression (SVR), using a nested cross-validation pipeline to predict tensile strength, elongation, and surface roughness. The results reveal significant data gaps in existing literature, with missingness exceeding 60% for critical parameters like fan speed and wall thickness. While the Random Forest model achieved high predictive accuracy for bulk mechanical properties, specifically a test-set R2 of 0.995 for PLA elongation, all models struggled with surface roughness, often yielding negative R2 values. This suggests that current process descriptors are insufficient to capture the stochastic nature of surface morphology. This work provides a foundational benchmarking dataset for the research community and highlights the necessity for stricter data mining protocols and more sophisticated feature engineering to achieve reliable predictive quality in material extrusion (MEX) polymers.

Abstract: With the Green Deal and the Circular Economy Action Plan, the European Union aims to replace half of the fossil-based raw materials in plastics with sustainable alternatives by 2030. In the plastic pipe industry, the use of post-consumer recyclates (PCR) remains very limited due to reduced material quality, economic hurdles, limited availability, non-specific classification requirements, and a lack of testing standards. This paper presents two interconnected contributions to the quality-assured use of PCR for buried utility infrastructure made from PE, PP, and PVC-U. First, a methodological framework, based on EN 13476, defines suitability as the intersection of material classification and application-specific requirements profile. A review of the current regulatory and technical situation reveals a systemic discrepancy: requirements profiles are oriented toward virgin material, while the scope of classification for PCR remains insufficiently defined. As a result, PCR is either used without adequate suitability assessment or blended with fillers, which limits the recyclability. Secondly, the review focuses on additive strategies, including restabilization, compatibilization, chain modification, and recyclate-compatible functional additives. These strategies are among the main technical solutions for closing the gap between PCR properties and the product's requirements, reducing filler dependency, and enabling the long-term use of PCR in safety-critical applications.

Abstract: Micro-nonuniformity, as a fundamental natural property, is widespread across a range of microscopic aggregate systems, such as polymer systems, biomacromolecular systems, and nanosystems. However, the construction of micro-nonuniform molecular systems has not yet been realized at the level of organic molecules with well-defined structural compositions. Inspired by the “chemical space” concept, I recently reported a study of the single-molecule mixture state; in this paper, I provide a detailed discussion of micro-nonuniformity and the hypothesis of a “single-molecule mixture state”, and propose a possible experimental approach for testing it.

Abstract: Currently, plastic pollution is a growing global issue due to its non-biodegradability, increasing demand for eco-friendly alternatives such as bioplastics. This study explores the development of bioplastic films from chickpea starch using a three-step molding process. In the first step, starch is extracted from chickpeas. The second step involves hydrolysis and plasticization of starch with glycerol in different ratios. In the final step, the modified starch is blended with polyvinyl alcohol (PVA) in varying ratios to produce the bioplastic films. The optimal formulation, CPS 1:2:2, exhibited strong performance (3.63 MPa TS, 623% EA, and 70.1° WCA). The bioplastic showed good physicochemical characteristics, confirmed by FTIR analyses, mechanical performance, and water contact angle, and demonstrated biodegradability, as confirmed by FTIR and SEM morphology.

Abstract: Shape-memory polymers (SMPs) are gaining significant attention for their ability to recover predefined shapes via external stimuli. Among thermally activated systems, biodegradable blends of polylactic acid (PLA) and polycaprolactone (PCL) are particularly promising for biomedical devices and soft actuators. This study develops a thermo-mechanical theoretical model to investigate the shape-memory behavior of a PLA/PCL composite blends under controlled thermal cycling. The framework integrates transient heat transfer, temperature-dependent elasticity, and viscoelastic dynamics to predict temperature evolution, deformation, and internal stress. The thermal response is computed via Newton’s law of convection, while the mechanical transition is described by a sigmoidal temperature and crystallinity-dependent Young’s modulus. Beam bending theory is employed to evaluate the spatial distribution of strain and stress. A parametric sensitivity analysis was performed to evaluate the influence of different parameters including the crystallinity grade, the convective heat transfer coefficient, glass transition temperature, and viscoelastic recovery constant. The theoretical study accurately reproduces the shape-memory cycle, quantifying performance through fixation and recovery ratios. This model provides a robust tool for the rational design and optimization of biodegradable smart polymer structures.

Abstract: Five modifications of polytetrafluoroethylene (PTFE) are considered as a modern alternative to PTFE as sliding layers of bridge bearing parts. Radiation-modified PTFE without additives and with nano-additives, as well as composites based on PTFE with bronze inclusions and nanomodified carbon fiber fillers, were investigated. Ultra-high-molecular-weight polyethylene (UHMWPE) and classic pure PTFE were considered as control samples. The thermomechanical properties of the materials were studied within the framework of dynamic mechanical analysis in the operating temperature range of bridge structures [−40; +80] °C. The exit zones from the linear theory of viscoelasticity were established for all the materials considered. Temperature dependencies of the storage module and the loss module were determined. Thermo-viscoelastic models of material behavior were constructed using a numerical identification procedure, experimental data, and simulation models. The thermomechanics of materials during the deformation of the spherical support part of the bridge were analyzed. Temperature dependencies of the parameters of the contact stress-strain state were determined with an average coefficient of determination R2 = 0.97 and an average error size RMSE = 0.092.

Abstract: Lignin is an abundant aromatic biopolymer generated as a major by-product in lignocellulosic biorefineries, and its efficient valorization is essential to improve process sustainability and economic viability. Among current upgrading strategies, the conversion of lignin into lignin-derived biochar (LDB) has emerged as a promising route due to its high carbon yield, scalable production, and tunable physicochemical properties. This review examines lignin-to-biochar conversion within the biorefinery context, emphasizing the interconnections between lignin structure, thermochemical processing, and resulting material properties. The influence of different technical lignins (kraft, organosolv, and soda) and conversion pathways, including pyrolysis and hydrothermal carbonization, is discussed. LDB materials exhibit strong potential in the removal of emerging contaminants, such as pharmaceuticals, pesticides, and PFAS, as well as in controlled release systems for agrochemicals. Despite recent progress, key challenges remain, including limited reproducibility across studies, insufficiently established predictive structure-property relationships, and the need for validation under realistic environmental conditions. Overall, LDB represents a scalable and versatile platform for lignin valorization, contributing to the development of integrated and sustainable biorefineries within a circular bioeconomy framework. This review provides a conceptual framework for the rational design of lignin-derived biochar within next-generation biorefineries.