Chemistry and Materials Science

Abstract: Ferrites are ceramic products made mostly of iron oxide mixed with other metal oxides, like cobalt, nickel, zinc, or manganese. They are frequently employed as a fundamental substance in the electrical and electronics sectors because of their variable magnetic features, relatively low eddy-current distortion at elevated frequencies, and excellent electrical resistance. Lanthanum ferrite (LaFeO₃) has unique electrical, optical, and dielectric characteristics, along with high chemical stability, making it a viable perovskite-type material. Magnesium replacement can affect the crystalline structure, defect chemistry, and charge transfer pathways in order to vary its functionality. Mg replacement affects the structural, dielectric, electrical, and optical properties of La_2-xMg_xFeO₃ metallic materials, as previous studies have shown. The goal of the present research is to use the sol-gel technique to manufacture La_0.75Mg_0.25FeO₃ and examine its structural, electrical, optical, and dielectric properties for prospective applications in sensors, photocatalysis, electronic equipment, telecommunications, and shielding purposes. In order to comprehend the impact of the magnesium substitution process on the material's (La_0.75Mg_0.25FeO₃) structural characteristics and analyze its capability for anticipated purposes. The research intends to analyze crystalline phase development, crystallite dimensions, morphological characteristics, a standard optical spectrum width, electrical conductivity, and temperature-varying dielectric activity. The sol-gel method was used to create a set of magnesium-doped lanthanum ferrites La_0.75Mg_0.25FeO₃, which were then sintered at different temperatures that is 100°C, 300°C, 600°C, and 900 °C. In this study, XRD analysis confirmed the orthorhombic phase of La_0.75Mg_0.25FeO₃. The most noticeable peak (110) exhibits switching, and the average crystallite (D) size falls between 7.2 and 8.5 nm. With rising annealing temperatures, the X-ray density (ρ_x) progressively dropped from 7.27 to 6.88 g/cm², whereas the dislocation density (δ) steadily increased from 4.2 to 5.2×10¹⁵ lines/m² as the temperature rose. The large surface area (7.5 to 13.6 m²/g) suggests the use of supercapacitors and other energy storage devices. As annealing temperature rises, a decreasing pattern in the direct band gap (4.09 to 3.87 eV) and indirect transition (3.33 to 3.13 eV) has been noted. The low value of the refractive index (0.1 to 0.3) means these nano-materials can be utilized in making cladding of fiber optics and in solar cells to make an anti-reflection coating layer. SEM results showed the non-homogeneous morphology.

Abstract: The features of the formation of the porous structure of a \(\mathrm{Zr(OH)_n(CO_3)_m}\)--\(\mathrm{ZnO}\) composite adsorbent, as well as its thermal and sorption properties with respect to \(\mathrm{CO_2}\), have been studied in relation to the life-support systems for closed environments. It has been established that the amorphous micro-mesoporous structure of the material is formed during the synthesis of the adsorbent at the hydrothermal treatment stage as a result of the hydrolysis of zirconium hydrocarbonate. The specific surface area and micropore volume of the material increase almost a hundredfold compared with the initial zirconium hydrocarbonate and amount to \(298~\mathrm{m^2/g}\) and \(0.120~\mathrm{cm^3/g}\), respectively. Zinc oxide acts as a stabilizing additive that mitigates the degradation of the porous structure of \(\mathrm{Zr(OH)_n(CO_3)_m}\) and of the adsorbent as a whole upon its contact with water vapor during operation, particularly during regeneration. The material exhibited a high sorption capacity for carbon dioxide under dynamic conditions (of the order of \(9\text{--}11.5~\mathrm{L/L}\) at a \(\mathrm{CO_2}\) content in the air mixture equal to \(0.4\text{--}1.0\%\)) and stability over long-term resource testing (4600 adsorption--desorption cycles), which makes it possible to recommend it for \(\mathrm{CO_2}\) capture and for the air revitalization of space complexes.

Abstract: Re-entrant structures can be configured into linear mechanical systems that combine the dynamics of unidirectional motion with structural stiffness. Linear technology is defined as a subset of drive and control engineering designed to handle cyclic dynamic loads—including the damping of mechanical vibrations—with high energy efficiency. Transient, repetitive loads are utilized to achieve precise positional changes, ensuring high performance and accuracy. By assembling individual re-entrant unit cells into columns, rigid systems can be created that expand precisely in the perpendicular direction when subjected to tension; the longitudinal and transverse displacements are linked by a negative Poisson's ratio. Such structures are suitable for generating linear mechanical motion along a straight path. The study investigated two versions of re-entrant linear structures designed and fabricated from metal: one based on interconnected torsion springs and another composed of struts connected via hinges to a single extension spring, equipped with guides. The spring-like nature of the structures ensured reversible behavior during stretching and unloading cycles. An effective Young's modulus was estimated based on experimental force-elongation relationships, and negative Poisson's ratio values were determined from measurements of elongation during stretching. The study demonstrated the feasibility of manufacturing linear auxetic structures using assembly techniques, highlighting their potential for engineering applications.

Abstract: This study presents results from comprehensive investigations of scapolite samples exhibiting natural or thermally induced photoluminescence. A range of analytical techniques, including single-crystal X-ray diffraction, Fourier transform infrared spectroscopy, Raman spectroscopy, photoluminescence spectroscopy and electron paramagnetic resonance spectroscopy was employed to characterize sulphur-related defect centers within the scapolite anionic cages. Differential scanning calorimetry combined with thermogravimetry and mass spectrometry was used to analyze the stages of degassing and quantify the volatile components. A new interpretation of the electron density distribution within the scapolite anionic cage has been proposed. This enables the localization of possible precursors of S2•- radicals, the later acting as luminescent centers. Key parameters, including atomic positions, occupancies, and bond lengths, were determined for the newly observed moieties. Furthermore, a novel methodology approach was developed to quantify SO42- and CO32- ratios in the structure based on the occupancy of their oxygen sites. Finally, the conditions necessary for the formation of persistent S2•- radicals in fluorescent scapolites were discussed, with an emphasis on the required cationic environment and charge-transfer conditions.

Abstract: Focusing on the evolution of anti-armor threats and material responses, this review traces the development of tank armor materials from rolled homogeneous armor steel to metal, ceramic, polymer-composite systems, and reactive protective structures. For kinetic projectiles, shaped-charge jets, long-rod penetrators, and top-attack threats, the response mechanisms and application boundaries of high-hardness steels, lightweight alloys, ceramic/fiber composite armor, confined ceramic-metal laminates, explosive reactive armor, and porous, slat, and bio-inspired structures are compared. Material-structure coupled mechanisms including adiabatic shear, impedance matching, and ceramic fracture are summarized. The reviewed literature indicates that armor design is shifting from single-property optimization toward coordinated trade-offs among hardness, toughness, density, spatial configuration, and system interfaces. Functionally graded materials, micro-laminated composites, damage-sensing interfaces, and materials informatics offer possible routes for lightweight design, multi-hit resistance, and maintainability. However, cross-material comparison remains constrained by differences in projectile type, impact velocity, angle of incidence, boundary conditions, and evaluation criteria. Engineering feasibility still requires validation through unified databases, multi-hit tests, environmental durability studies, manufacturing consistency assessment, and cost analysis.

Abstract: Coconut shell (CS), an abundant by-product of the coconut-processing industry, is a lignin-rich feedstock for renewable aromatic materials. In this study, H₂SO₄-assisted ethanosolv fractionation of extractive-free CS was optimized using a four-factor Box–Behnken design (ethanol 50–90% v/v, H2_SO₄ 0.2–2.0% w/w, 100–190 °C, 15–90 min). Crude lignin yield (0.2^–11.2%) was governed mainly by temperature and time, whereas total phenolic content (TPC; 284.7–827.2 mg GAE g⁻¹) depended on the ethanol and acid concentrations and their interactions with time. Coconut shell lignin obtained at 70% ethanol, 1.1% H₂SO₄, 190 °C and 90 min (CSL; 11.1% yield) was characterized using commercial alkali lignin (AlkL) as a benchmark. CSL contained 88.0% Klason lignin, 7.8% residual carbohydrate (mainly xylan) and 1.0% ash, and showed a lower sulfur content than AlkL (0.6 vs. 2.5 wt%, EDX) without the crystalline sodium sulfate detected in AlkL. 2D HSQC NMR revealed that CSL is a p-hydroxybenzoate–guaiacyl–syringyl lignin that retains β-O-4′ aryl ether linkages, whereas AlkL is a guaiacyl-type lignin largely depleted of β-O-4′ units. Although its TPC was lower (328.0 vs. 380.1 mg GAE g⁻¹), CSL scavenged ABTS and DPPH radicals about twice as effectively as AlkL (IC50 0.72 and 1.19 vs. 1.47 and 2.94 mg mL⁻¹) and absorbed 4.0- and 3.7-fold more UVB and UVA radiation. H₂SO₄-assisted ethanosolv fractionation therefore yields a low-sulfur, less-condensed lignin with promising antioxidant and UV-absorbing functionality.

Abstract: The increasing concentration of atmospheric CO₂ has intensified the search for sustainable technologies capable of converting this greenhouse gas into valuable fuels and chemicals. Among the available approaches, thermocatalytic, photocatalytic, and electrochemical CO₂ reduction have emerged as key strategies for carbon valorisation. In this regard, biochar-derived materials have recently attracted growing attention due to their renewable origin, tunable porosity, rich surface chemistry, and ability to support active catalytic sites. These properties enhance CO₂ adsorption, activation, and charge-transfer processes, making biochar a promising platform across multiple CO₂ reduction pathways. This review provides a critical overview of recent advances in thermocatalytic, photocatalytic, and electrochemical CO₂ reduction using biochar-based materials, highlighting the relationship between material properties and catalytic performance. Particular attention is given to integrated capture-conversion systems, where biochar enables the coupling of CO₂ adsorption and catalytic transformation within a single material architecture. Current challenges and future research directions are discussed to support the development of scalable biochar-based technologies for sustainable carbon utilisation.

Abstract: Solution Combustion Synthesis (SCS) continues to emerge as a green synthesis method for the preparation of advanced inorganic nanomaterials with tailored physicochemical properties. This review discusses the basic concepts of fuel–oxidizer ratios in solution combustion synthesis and explores in detail the effects of different types of fuel-oxidizer mixtures, oxidizer nature, fuel type, experimental conditions, and targeted material properties on the optimization of combustible mixtures. Furthermore, highlights on the impact of varying fuel–oxidizer ratios on powder properties and their performance in different applications such as biosensing, catalysis, photocatalysis, and electrochemical energy storage were analyzed. Findings demonstrate that careful modulation of the combustible mixture enables structured tuning of nanomaterial properties for specific technological applications. However, despite the significant progress achieved in solution combustion synthesis, challenges still exist with controlling the combustion reaction, carbonaceous impurities, scalability, and morphology regulation. Hence, the review suggest that future perspectives should focus on the integration of advanced thermodynamic modelling, real-time in situ characterization techniques, and the development of novel fuels and oxidants to achieve improved combustion precision and reproducibility. These advancements are expected to enhance the scalability and industrial applicability of SCS while enabling the design of next-generation functional nanomaterials with superior performance and sustainability.

Abstract: Sodium-ion batteries are emerging as a complementary electrochemical energy-storage technology to lithium-ion batteries, particularly for stationary, grid-scale, and other cost-sensitive applications. However, assessing the practical relevance of newly developed sodium-ion materials remains challenging because early-stage electrochemical evaluation is still dominated by Na-metal half-cells. These configurations are indispensable for establishing reversible capacity within defined voltage windows, redox behavior, kinetic characteristics, structural evolution, initial Coulombic efficiency, and electrode-specific interfacial processes, but they do not reproduce the finite sodium inventory, electrode balancing, realistic loading, shared electrolyte environment, or coupled ageing that govern practical full cells. This review develops a translational framework for evaluating sodium-ion battery materials across successive levels of experimental realism. It first defines the appropriate role of half-cell testing and then examines the transition toward realistic composite electrodes and balanced full cells, with particular emphasis on mass loading, areal capacity, electrode density, N/P ratio, sodium-inventory management, electrolyte amount, full-cell energy, Coulombic efficiency, impedance evolution, and reproducibility. Interfacial chemistry is considered in terms of the transition from electrode-specific SEI/CEI formation to chemically coupled full-cell behavior, including interelectrode cross-talk, transition-metal migration, electrolyte-derived species, gas evolution, and their consequences for sodium loss and impedance growth. Operando and in situ characterization are discussed according to an architecture–mechanism–diagnostic framework in which X-ray methods, vibrational spectroscopies, imaging and microscopy, impedance analysis, and multimodal approaches are matched to the degradation processes they are intended to resolve under increasingly representative cell conditions. Finally, a staged validation pathway is proposed, progressing from material-level half-cell characterization to realistic electrode validation, balanced full-cell testing, operando diagnosis, and prototype-level assessment. By distinguishing what each experimental stage can establish and which questions require more representative architectures, this review provides a framework for assessing whether favorable material-level performance can be translated into practical sodium-ion battery operation.

Abstract: Nanocellulose was produced from hemp hurds and corn cob using a citric-acid-assisted chemical–mechanical route optimized by response surface methodology (RSM). Extraction cycle number and probe-sonication time were evaluated as process variables, with FTIR-derived total crystallinity index (TCI) and SEM-derived fibril size as responses. The selected conditions were 3 cycles/120 min for hemp hurds and 3 cycles/75 min for corn cob, yielding experimentally observed fibril sizes of 80 nm and 56.6 ± 8.8 nm, respectively. The optimized nanocelluloses were modified with nominal Cu loadings of 15, 25, 50, and 75 wt%. Cu incorporation reduced low-frequency impedance by more than 96% relative to bare nanocellulose and markedly increased cycle-5 passed charge, although the loading dependence differed between biomass sources. The 50 wt% formulations provided the most consistent combination of relatively low impedance and high passed charge across both sources. TGA revealed source-dependent increases in retained nonvolatile residue with Cu loading, while XRD confirmed face-centered cubic metallic Cu together with weaker cellulose-related reflections. The results demonstrate that extraction history and biomass source jointly govern nanocellulose structure and the electrochemical response to Cu modification.

Abstract: Homoleptic mercaptides of n-dodecanethiol (i.e., organosulfur compounds with formula: Me(SC₁₂H₂₅)_X, where X is the oxidation state of the metal, Me) are soluble, at low concentrations, in paraffin wax, and these solid solutions can be used as fuel for fabricating paraffin candles with colored flames (or UV/NIR-light emitting flames). Depending on the nature of the required metal, the preparation of n-dodecanethiol salts can be done by adopting different synthetic strategies. Here, the main methods for synthesizing n-dodecanethiol mercaptides are described; these methods are based on: (1) neutralization of the thiol with metal hydroxide in an alcoholic medium, (2) double-displacement reaction in acidic or basic environments, (3) synthesis based on the mercaptide solubility product (K_SP) in water, and (4) direct reaction of the thiol with the elemental metal in an active form. The most important issues related to the preparation of the mercaptide through these chemical reactions (e.g., mercaptide purification, variation of the metal's oxidation number, mercaptide XRD characterization, etc.) are also analyzed in some detail.

Abstract: Traditional gels are generally constructed using colloidal nanoparticles as fundamental building blocks, which confines gel skeletons within nanoscale architectures and imposes intrinsic constraints on the atomic-level regulation of network structures. Recent advances in the synthesis of ultralong metallic single-atom chains, exemplified by the carbon-sheathed Cu single-atom chains reported in recent literature, offer an intriguing possibility to expand the boundary of gel assembly. With the assistance of protective carbon sheath, such sub-nanometer one-dimensional atomic chains may be dispersed as unconventional colloidal units in liquid media, and potentially intertwine to form continuous three-dimensional gel networks upon concentration adjustment or mild crosslinking treatment. In this review, we tentatively put forward the new concept of atomic chain gels (ACGs), not as a fully established material system, but as a conceptual hypothesis for discussion within the community. We first revisit the classical definitions of colloids and gels, clarify the structural boundary from isolated single atoms, sub-nanometer clusters to stabilized metallic single-atom chains. We further discuss the plausible assembly pathways, unique thermodynamic features including orientational entropy of one-dimensional atomic chains, and prospective application scenarios in energy storage and electrocatalysis. We sincerely hope this preliminary conceptual attempt can inspire peer researchers and stimulate open discussions on atomic-scale gel materials.

Abstract: As a new catalytic material with excellent performance, nitrogen (N)-doped carbon nanocages with high surface reactivity has extremely broad application prospects in electrocatalysis. In this study, N-doped graphene-like carbon nanocages (NGCNs) modified by trace nickel (Ni) species (possible components are: single atoms and clusters) were prepared from nickel acetate, carbon source and nitrogen source by thermal decomposition acid etching methods. The excess Ni was removed by acid etching, and finally a three-dimensional (3D) NGCNs-supported atomic nickel catalyst was obtained. Then the catalyst was characterized by scanning electron microscope (SEM), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). At the same time, the 3D NGCNs-supported atomic nickel catalyst was assembled into oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) electrodes for electrochemical evaluation, and the possible synergistic effect betwen Ni single atom and Ni cluster or N-doped carbon and Ni in NGCNs was also suggested.

Abstract: Thermal management by passive radiative cooling materials can save energy and reduce emission of green-house gas remarkably compared with traditional air-conditioner cooling. However, few of these materials are degradable, thus their disposal may lead to another environmental problem. Meanwhile, the COVID-19 pandemic and other infectious diseases have raised the requirement of hygienic and antimicrobial performance. This work reports a discovery that polylactic acid oligomer (PLAO) material possesses radiative cooling effect, wide-spectrum antimicrobial property and degradability, simultaneously. The radiative cooling effect is attribute to the hexagonal microsphere geometry and nanotexture of polylactic acid oligomer (PLAO) crystals, which enhance the reflectivity in the solar spectrum through multiple scattering effect and exhibit high emissivity in the mid-infrared atmospheric window. Hierarchically porous PLAO coating material realizes an apparent temperature reduction of 6.8 ℃ under irradiation of solar spectrum (AM 1.5). The material also shows wide-spectrum antimicrobial and anti-viral properties against coronaviruses (including COVID-19 virus), gram-positive bacteria, gram-negative bacteria, fungi and multidrug resistant bacteria.

Abstract: ZnIn₂S₄ is a visible-light-responsive ternary sulfide used in photocatalytic hydrogen evolution, CO₂ conversion, pollutant treatment, selective organic reactions and photoelectric sensing. Its layered structure and adaptable surface chemistry make it convenient for preparing nanosheets, porous assemblies, defect-containing surfaces and semiconductor junctions. These structural changes, however, influence different steps of a reaction, and the measured performance depends strongly on the donor, reactor, illumination and product analysis. This review examines ZnIn₂S₄ from the working structure to the measured reaction or sensing signal. The structural basis is followed by discussion of morphology, vacancies, composition, cocatalysts and heterojunctions. Representative applications are then considered with attention to product selectivity, carbon or oxygen balance, sulfide stability and analytical validation. Particular care is taken to distinguish sacrificial hydrogen evolution from overall water splitting, pollutant disappearance from mineralization, and a large photocurrent from a reliable sensor response. The aim is to summarize the available evidence while indicating which controls are still needed for meaningful comparison.

Abstract: The ferrielectric properties of layered CuInP₂S₆ (CIPS) are highly sensitive to stoichiometry and growth-induced defects. Here we systematically compare crystals grown by chemical vapor transport and the Bridgman–Stockbarger method with Cu- and In-enriched samples, combining compositional analysis, dielectric spectroscopy, uniaxial-pressure measurements, Raman spectroscopy, piezoresponse force microscopy and first-principles calculations. The transition temperature increases systematically from 307 K (Bridgman) to 312 K (Cu-enriched), 317 K (gas-transport) and 322 K (In-enriched). In enrichment is consistent with spontaneous CIPS/In₄/₃P₂S₆ phase segregation that generates effective positive chemical pressure, stabilizing the ferrielectric state and producing a strongly biased, pinned domain configuration. Cu enrichment produces the opposite response—lower TC, enhanced dielectric loss and a fragmented domain morphology—characteristic of a negative-pressure-like perturbation of the Cu-ion energy landscape. Landau–Ginzburg–Devonshire analysis and density-functional calculations provide a unified microscopic picture based on Cu-ion configurational freedom and interlayer coupling. Growth defects act as an independent source of domain-wall pinning. Together, these results establish stoichiometry and synthesis conditions as practical tools for engineering ferrielectric order in van der Waals CIPS.

Abstract: The increasing use of zinc oxide nanoparticles (ZnO-NPs) in agricultural and technological applications raises concerns regarding their potential effects on plant development. In this study, ZnO materials were synthesized using flower, stem, and leaf extracts of Tithonia diversifolia and evaluated for phytotoxicity in Lactuca sativa. X-ray diffraction confirmed the hexagonal wurtzite structure, with crystallite sizes ranging from 25.6 to 34.8 nm. SEM revealed fine granular features assembled into larger agglomerates, while EDS showed differences in elemental composition and Zn/O atomic ratios, with a minor Ca signal detected only in ZnO-L. FTIR revealed Zn–O-related vibrations and differences in the vibrational characteristics of the thermally treated materials. Phytotoxicity assays showed distinct responses among the three materials. ZnO-F produced the lowest overall effect on seedling development, whereas ZnO-S caused the greatest inhibition of radicle and hypocotyl elongation. ZnO-L exhibited a biphasic response, with hypocotyl elongation above the control at 20–60 mg L⁻¹ and inhibition at higher concentrations, consistent with hormesis. Overall, the results indicate that the plant extract source influences the physicochemical characteristics and phytotoxic behavior of the resulting ZnO materials, potentially through the combined influence of multiple material properties.

Abstract: Urea-derived graphitic carbon nitride (g-C₃N₄) underwent to chemical treatment in a strongly oxidizing H₂SO₄/HNO₃/H₂O₂ environment, followed by dialysis against water. XRD and SEM measurements revealed significant disruption of the layered polymeric framework, including loss of hydrogen-bond-mediated order, partial depolymerization into melem-based units, and the formation of rod-like melem-hydrate superstructures. FTIR spectra indicated that chemical treatment resulted in the loss of the heptazine structure and emergence of melem/triazine vibrations. Consistent disruption of the C–N framework was also observed in XPS spectra, which showed a reduced contribution of nitrogen species associated with inter-triazine bridging. Mott–Schottky analysis yielded potential values suggesting the presence of additional electronic states in the chemically treated sample. This aligns with EPR spin-trapping results, which showed approximately a 2.5-fold decrease in superoxide radical anion generation upon visible light irradiation compared to the parent compound.

Abstract: Friction stir welding (FSW) is a promising solid-state joining process for magnesium al-loys that avoids defects characteristic of fusion welding. In the present study, a three-dimensional, fully coupled thermomechanical model of FSW of two 3.0-mm-thick MA2-1 (AZ31B) alloy plates was developed using the Coupled Eulerian–Lagrangian (CEL) approach in Abaqus/Explicit. The constitutive behavior of the material was de-scribed using the Johnson–Cook model (A = 172 MPa, n = 0.456, m = 0.90), while contact interaction was represented by a modified Coulomb–Tresca friction law (μ = 0.40, δ = 0.60). A parametric study of 11 configurations was performed by varying the shoulder diameter R_sh (6–12 mm), pin diameter R_pin (2–4 mm), rotational speed ω (600–1200 rpm), and traverse speed v (60–180 mm/min). A functional specialization of the parame-ters was established: R_sh dominates the thermal regime (exponent +0.58 for T_peak) and the stress state (−1.67 for σ_mean); R_pin controls the width of the stirring zone (W_mix, exponent +0.88); and rotational speed ω is the key factor governing AS/RS deformation asymmetry (K_asm(PEEQ) = 1.10–1.40). Power-law regression equations were obtained for T_peak, σ_mean, PEEQ_max, and W_mix, with R² ≥ 0.95. Spatial correlation analysis confirmed the independence of the thermal and deformation zones, with r(T, PEEQ) = 0.07. Principal component analysis (PCA) identified two dominant mechanisms: a 'com-mon interaction zone' (PC1, 44.7%) and an HAZ–TMAZ antiphase (PC2, 23.7%).

Abstract: The combined influence of chemical structure and cellular morphology on the performance of high-density polyurethane foams has received limited attention. In this work, three foams based on a commercial petrochemical polyol (SD441) were compared with three foams produced from a mixture of epoxidized soybean-oil polyol and glycerol at densities ranging from approximately 100 to 300 kg/m³. The biobased foams exhibited substantially lower compressive strength than the petrochemical materials, with longitudinal strength ranging from 0.60 to 4.07 MPa compared with 1.03 to 8.92 MPa for the petrochemical foams. Electron microscopy revealed larger cells, greater anisotropy, and pronounced morphological heterogeneity in the biobased materials, particularly at higher densities. Despite their lower initial storage modulus, the biobased foams exhibited greater resistance to thermally induced softening: at 170 °C, they retained approximately 32–39% of their initial storage modulus, compared with only 6–8% for the petrochemical foams. A second DMA heating run, together with FTIR and DSC results, indicated irreversible structural changes during the first heating cycle. The reduction in residual isocyanate content and changes in the carbonyl and amide II regions were consistent with further network development during heating, suggesting additional post-curing in the biobased foams. DSC identified two exothermic events in the biobased materials: a broad event between 60 and 245 °C, consistent with additional reactions, and a second event between approximately 255 and 300 °C that overlapped with the onset of thermal degradation observed by TGA. In contrast, the type of blowing agent strongly influenced the degradation temperature but had no significant effect on mechanical performance within the investigated density range. Overall, the results demonstrate a distinct trade-off between mechanical and thermomechanical performance in high-density biobased polyurethane foams, highlighting the influence of polyol molecular architecture, network development, and cellular morphology on their behaviour.