Search Results (223)

This paper examines how international crude-oil price movements are transmitted to natural-rubber prices through the petrochemical–synthetic-rubber chain, with implications for Thailand as the world’s leading natural-rubber exporter and China as the dominant consumer. Using monthly data from April 2003 to March 2026 on the OPEC reference basket, butadiene, styrene–butadiene rubber (SBR), and the Shanghai natural-rubber benchmark, the analysis combines a nonlinear ARDL specification with a Pesaran–Shin–Smith bounds test, a long-run association decomposition into direct and synthetic-rubber-mediated components with bootstrap inference, and a threshold-NARDL extension that conditions the decomposition on the inventory state. Three findings stand out. First, the synthetic-rubber-mediated component accounts for approximately three-quarters of the estimated oil–natural rubber long-run association (73.5 percent, 95 percent bootstrap CI [60.6, 87.2]), with the residual direct component accounting for the remainder. Second, long-run pass-through is directionally consistent with concentration in the synthetic-rubber component, although Wald tests do not reject symmetry at conventional levels for either the synthetic-rubber component (Wald $p=0.135$) or the direct oil component ($p=0.166$). Third, the synthetic-rubber-mediated share is consistently larger in low-inventory regimes by 26 to 66 percentage points across three alternative regime variables, although the magnitude amplification of asymmetric pass-through itself is not robust. Asymmetric local projections and a Diebold–Yilmaz spillover analysis are reported as complementary horizon-indexed and network checks. The results imply that the synthetic–natural rubber spread, conditioned on the inventory state, may be more informative for natural-rubber price-risk monitoring than crude-oil prices alone. These findings have implications for commodity price-risk monitoring, export-income exposure, and stabilisation design in rubber-exporting economies. Because crude-oil shocks are not externally identified, all estimates are interpreted as decompositions of long-run association rather than causal mediation effects. Full article

Introduction: Microplastic (MP) contamination can endanger marine ecosystems and indirectly affect the well-being of humans through the ingestion of marine species. While most research investigates the digestive system, such as the gills and gastrointestinal tract of fish, it still fails to address a major oversight in understanding MP deposition in edible tissues, which is the primary route of human exposure. The differences in contamination levels among pelagic, demersal, and benthic fish in Malaysian waters remain poorly understood. This preliminary study uses Laser Direct Infrared Imaging (LDIR), a new, high-resolution, automated technique, to examine synthetic MP contamination in the edible portion of fish. Materials and Methods: The MPs were extracted from the edible tissue of three fish species representing pelagic (Fish A), benthic (Fish B), and demersal (Fish C) using KOH and sieved onto a gold mesh filter before analysis using LDIR. Results and Discussion: LDIR identified 162 MP particles, revealing clear differences by polymer type and habitat. Pelagic species mostly contained polyethylene (PE) and rubber (n = 8). Demersal species had mostly polyethylene terephthalate (PET) with small amounts of PE and rubber (n = 57). Benthic species showed the highest load, dominated by PET and polypropylene (PP) (n = 97). The morphological assessment of the MPs indicated that the polymers in pelagic fish were smaller, with an area of 2047.82 µm² and a circularity range of 0.14–0.74, indicating consistent shape. Conversely, MPs are irregular and larger in benthic fish, with areas up to 38,837.50 µm² and circularities ranging from 0.02 to 0.81. This pattern reflects specific accumulation related to habitat and potential environmental degradation processes. Conclusions: This preliminary study demonstrates the effectiveness of LDIR for detecting MPs in edible fish tissues. The findings provide a fundamental dataset on MP contamination in edible tissue and emphasize its distribution across ecological zones. Nevertheless, broader research is required to substantiate these data and assess the implications of MP contamination for the environmental stability of human and marine well-being. Full article

Styrene–butadiene rubber (SBR) is one of the most widely used synthetic elastomers. However, the unsaturated C=C bonds in its backbone limit its long-term stability under harsh service conditions. Furthermore, conventional sulfur vulcanization forms irreversible covalent crosslinked networks, which fundamentally hinder the recyclability and reprocessability of SBR, resulting in resource waste and environmental burdens. In this work, SBR was used as the starting material. Through epoxidation and subsequent hydrogenation, followed by an epoxy ring-opening reaction, 3-aminophenylboronic acid (m-APBA) was introduced into the polymer chains, constructing a novel hydrogenated SBR with reversible dynamic cross-linking characteristics (HESBR-APBA). The resulting material exhibits superior mechanical properties compared to conventional hydrogenated SBR (HSBR) without any external additives. Notably, the HE7.4SBR-0.75APBA sample achieved a tensile strength of up to 14 MPa and retained over 95% of its original strength after multiple reprocessing cycles, demonstrating excellent mechanical stability and reprocessability. This study provides an effective molecular design strategy for balancing high mechanical performance and recyclability in hydrogenated SBR and offers new insights for developing reprocessable rubber material. Full article

This study investigates the application of NDTs for the detection of sub-surface defects in an ancient book, with the aim of improving conservation methods in the field of cultural heritage. A sequence of thermographic images in a solar loading thermography (SLT) scenario was acquired during a diagnostic campaign in Harbin, China, to identify four distinct fabricated dowels made of Wool, Rubber, Teflon^®, and Synthetic material. The images were processed in two ways: the first combined advanced image-processing methods: pre-processing via MdFIF, post-processing, PCT and RPCT, applied both to the original sequence and to the MdFIF-filtered thermograms. The second approach employed numerical simulations in COMSOL Multiphysics^® to develop a predictive thermal model. The comparison of localized thermal anomalies obtained from the two approaches demonstrated the capability of NDTs to reliably reveal artificial defects, confirming their suitability for diagnostic conservation. Overall, the integration of advanced image processing with numerical simulation enhances diagnostic accuracy, particularly for subtle or low-contrast anomalies, thereby enabling more informed condition assessment and supporting rapid, targeted, and preventive conservation strategies. Full article

Botrytis cinerea poses severe postharvest losses in horticultural products, while synthetic fungicides raise food safety concerns. This study developed a GRAS-compliant antifungal strategy using vapor-phase Cymbopogon citratus essential oil (EO). GC-MS revealed citronellal (17.06%) as the dominant bioactive compound. The EO exhibited superior vapor-phase activity against B. cinerea, with EC₅₀ of 14.69 µg/mL (mycelial growth) and MIC of 7.81 µg/mL (spore germination), significantly lower than direct-contact efficacy (p < 0.05). Mechanistic analysis revealed a tripartite mode of action—rapid membrane disintegration (48% electrolyte leakage within 4 h), suppression of ROS defense enzymes (SOD/CAT/POD inhibition > 50%), and disruption of mitochondrial energetics (SDH activity reduced by 58.1%)—which induced irreversible cellular collapse. This multi-target strategy mitigates resistance development, a key limitation of single-mode fungicides. In commercial-scale trials, EO fumigation (125 µg/mL) reduced cherry tomato decay by 81.9–92.6% during 28-day storage, while maintaining firmness (15.9% higher than control) and nutritional quality (titratable acidity (TA) and total sugar content (TSC)). Notably, the vapor-phase EO also exhibited potent inhibitory activity against the spore germination of rubber tree powdery mildew (EC₅₀: 3.19 µg/mL), demonstrating its broad-spectrum antifungal potential. This finding significantly expands the application scope of C. citratus EO from postharvest preservation to preharvest crop protection. This work provides a scalable, residue-free alternative to synthetic fungicides for industrial postharvest applications. Full article

Bicycle tires and inner tubes constitute a growing waste stream mainly composed of natural rubber, butyl rubber, synthetic elastomers, carbon black, and reinforcing materials. Their multi-material structure and highly crosslinked networks make their recycling challenging, yet efficient recovery is essential for advanced circular economy practices. This review summarizes the current and emerging strategies for recycling bicycle tires and inner tubes. It first outlines the materials and additives present in tire casings and butyl inner tubes, which determine their recycling behavior. Mechanical pre-processing methods, including shredding, grinding, and fiber/steel separation, are presented as essential feedstock preparation steps. Thermochemical approaches, such as pyrolysis and thermolysis, are discussed with emphasis on producing value-added fractions, including pyrolysis oil, recovered carbon black, and fuels. Solvent-based feedstock recycling and chemical dissolution are highlighted as promising routes for selective recovery of rubber polymers and additives. Physical, chemical, and biological devulcanization methods are also reviewed for their potential to restore partial processability to reuse reclaimed rubber. Finally, current and prospective applications of recycled materials are discussed, and key challenges with future research needs are identified, including improving devulcanization efficiency, expanding collection systems, and increasing the value of recovered products. Full article

The article studies the influence of chlorosulfonated polyethylene CSM 40 as a compatibilizer on the curing characteristics of the rubber compound, dynamic mechanical analysis, morphology, physico-mechanical and performance properties of vulcanized rubber based on a compound of ethylene propylene diene monomer EPDM S 501A and nitrile butadiene NBR 2645 rubbers. DMA studies indicate that the temperature dependence of tanδ for vulcanizates with and without a compatibilizer based on EPDM S 501A/NBR 2645 at a ratio of 75/25 parts per hundred parts of rubber (phr) has a bimodal character, which indicates the incompatibility of the rubber phases. The temperature dependence for EPDM S 501A/NBR 2645 vulcanizates (25/75 phr) with and without a compatibilizer has a monomodal form, which characterizes the improved compatibility of the rubber phases. SEM showed that a clearly defined microporous structure is observed on a cleavage of vulcanizate sample EPDM/NBR (25/75 phr) without a compatibilizer; with the addition of CSM 40, this feature is retained, but becomes less pronounced. It is shown that vulcanizates containing the compatibilizer CSM 40 are characterized by increased strength properties and hardness compared to vulcanized rubber without a compatibilizer. It was established that the vulcanized rubber based on EPDM S 501A/NBR 2645/CSM 40 (25/75/5 phr) is characterized by the smallest changes in the elastic-strength properties and hardness of vulcanizates after a day of thermo-oxidative aging in air and their weight after exposure to industrial oil I-20A and standard petroleum fluid SZhR-1 at room temperature among vulcanizates based on EPDM S 501A and NBR 2645. The vulcanizate of the rubber compound, including a compound of EPDM/NBR (25/75 phr) with a compatibilizer CSM 40 in an amount of 5 phr (2.88 wt.%), is characterized by stable physico-mechanical properties and improved performance properties. This rubber compound can be used for the manufacture of rubber products operating under the influence of oils and hydrocarbon environments. Full article

This study investigates the influence of synthetic fibers and rubber powder derived from end-of-life tires (ELTs) on the rheological behavior of asphalt mastics composed of paving-grade bitumen and mineral filler. Nine asphalt mastic formulations were prepared with varying fiber and rubber contents, reflecting the composition of stone mastic asphalt mixtures. Dynamic shear rheometer tests were conducted to assess dynamic stiffness modulus, phase angle, non-recoverable creep compliance, and elastic recovery. The results demonstrated that ELT-derived additives significantly enhanced high-temperature stiffness and elasticity, while maintaining satisfactory viscoelastic balance at lower temperatures. Synergistic effects between fibers and rubber were observed, improving both non-recoverable compliance and percent recovery, particularly at elevated shear stresses. Prolonged exposure to production temperatures (175 °C) confirmed the thermal stability of the modified mastics, with the most notable performance gains occurring during the first hour of heating. Based on the findings, it was concluded that ELT-based fiber–rubber additives can improve high-temperature performance of asphalt mastics without negative effects in intermediate and, possibly, also low service temperatures. This permits expanding the use cases for these kinds of additives beyond the role of inert stabilizers in stone mastic asphalt to an active modifier for extending asphalt mix performance. Full article

Coatings based on graphene nanostructures represent one of the most promising solutions for protecting metals from corrosion. However, their application remains unprofitable due to the high production costs, which are caused by the imperfections in graphene nanostructures synthesis methods. Therefore, this work utilized few-layer graphene particles synthesized via self-propagating high-temperature synthesis for coating fabrication. The effectiveness of these coatings in protecting metals against corrosion was tested in a salt spray chamber. It was found that the synthesized coatings provide excellent protection for the steel substrate against corrosion, and their effectiveness is significantly higher than that of polymer coatings based on epoxy resin. A hypothesis was proposed to explain the high efficiency of the coatings based on few-layer graphene particles. This is attributed to their low defect density (absence of Stone-Wales defects in their structure) and the presence of multiple layers, which enhances the barrier effect. Full article

This paper presents the effect of modifiers on the properties of a mixture of asphalt concrete with bitumen emulsion (ACBE). The mineral-asphalt mixture is the only one that can be produced using the cold-mix technology (CMA). The theoretical part of the article details the characteristics of the methods for producing mineral-asphalt mixtures in terms of their production temperature. Thus, hot (HMA), half-warm (H-WMA), warm (WMA) and cold (CMA) mixtures are discussed. The research section presents the design of the asphalt concrete composition with bitumen emulsion, the research methods, the experiment design and the research results. The design of the mixture of asphalt concrete with bitumen emulsion was carried out in accordance with the guidelines set out in EN 13108-31. In the experiment, Portland cement (C), bitumen emulsion (A), synthetic latex (styrene-butadiene rubber SBR) (B) and redispersible polymer powder EVA (polyethylene-co-vinyl acetate) (P) were used as modifiers. Twenty-four mixtures were designed as part of the experiment, according to the 3⁴ experiment design. The following physical and mechanical properties were assessed in the design of the research: air void content V_m, water ab-sorption n_w, indirect tensile strength ITS and IT-CY stiffness modulus. When analysing the research results, the authors observed a noticeable impact of the content of asphalt (A) and synthetic latex (B) on the air void content V_m. A significant effect was also observed for the interaction of Portland cement (C) and redispersible polymer powder (P) on the indirect tensile strength ITS. The next step was the optimisation of the ACBE mixture composition, which effect made it possible to identify the optimum amounts of modifiers in the mixture of asphalt concrete with bitumen emulsion (ACBE), which constituted recommendations for the requirements for mixtures of asphalt concrete with bitumen emulsion. Full article

Coatings based on graphene nanostructures exhibit high thermal conductivity and are capable of effectively protecting materials from the negative effects of ultraviolet radiation. However, due to the imperfections of the methods for synthesizing graphene nanostructures and coatings based on them, the practical application of such coatings remains unprofitable. This paper presents the results of a study of the thermal conductivity and UV-protective properties of coatings synthesized by chemically crosslinking few-layer graphene particles on ABS plastic substrates. Few-layer graphene particles synthesized under self-propagating high-temperature synthesis conditions were used as the starting material for the coating synthesis. The synthesized coatings were found to have a thermal conductivity of 244 W/(m × K) and are capable of effectively protecting ABS plastic substrates from the negative effects of UV radiation, allowing the products to maintain their required strength characteristics. The high productivity of the method for synthesizing few-layer graphene (up to 10 kg/month at the laboratory production level), as well as the simplicity of the method for synthesizing coatings based on it, allows us to hope for the cost-effectiveness of such coatings. Full article

Ionomers are promising materials because ionic interactions and their reversible clustering provide sensitivity to stimuli and facilitate energy dissipation, polymer miscibility, and ion transport. The existence of a wide variety of interacting ionic groups and their associated macromolecular structures provides the basis for considering the supramolecular organization of ionic polymeric materials as a factor determining the emergence of specific properties. The main structural elements of ionomers are ionic clusters, and the properties of ionomers are determined by their sizes and size distribution. Ionomers are attractive for use in composites, actuators, coatings, dyed textiles, adhesives, shape-memory and self-healing materials, water purification membranes, and ion-exchange membranes for fuel cells and batteries. This paper presents a review of the macromolecular structure and supramolecular organization of ionomers and their properties, depending on the basis of their ionic functionalization. The ionic functions of ionomers are determined primarily by the type of ion (cations or anions) that serves as the basis for their functionalization. Ionomers containing both anionic and cationic pendant ions are considered, with attention given to the influence of the nature of the counterions used on the properties of ionomers. Full article

Mushroom mycelium-based biomaterials (MMBs) are sustainable materials derived from fungal species and lignocellulosic substrates. In this study, fresh specimens of Panus ciliatus and P. subfasciatus collected from mixed deciduous forests in Chiang Rai Province, Thailand, were identified through a combination of morphological characteristics and phylogenetic analyses based on the ITS region. Panus ciliatus is reported as a new geographical record from Thailand. This is the first comprehensive study on MMB samples developed using mycelia of these species and rubber sawdust for their physical, mechanical, hydrodynamic, and chemical properties. Additional analyses included FTIR spectroscopy, thermogravimetric analysis, flammability testing, and soil burial degradability. Based on the material properties and successfully developed prototypes, the MMBs are potential in packaging, indoor uses, construction, and insulation purposes, as an alternative to conventional synthetic materials. Notably, Ashby chart of mechanical properties showed the MMB could substitute foam. Thermogravimetric analysis of MMB showed thermal stability with weight loss approximately 50–60% at 293–298 °C. Soil burial of MMB for 90 days shows cumulative weight loss exceeding 60% proving biodegradable. Additionally, a new approach for mycelial viability maintenance is described and verified, addressing the problem to maintain vigorous mycelium. Full article

Additive manufacturing has significantly advanced patient-specific medical devices, particularly for hard tissue repair, yet applications in soft tissue remain limited. Existing approaches for 3D-printed soft tissue devices employ mainly biogels and bioinks for regenerative purposes, while synthetic grafts for tendons and ligaments remain non-customizable in shape and mechanics. This study investigates the mechanical performance of 3D-printed thermoplastic polyurethane (TPU) elastomers as a function of printing parameters, informing customizable connective tissue graft designs. Type C dogbone specimens (n = 180) of three replicates each of parameter combinations from material shore hardness, presence of anchoring within the lattice, infill patterns, and infill density were printed and tested following modified ASTM D412 standards for vulcanized rubber and elastomers. The measured mechanical properties are elastic modulus, tensile yield stress, yield strain, ultimate tensile strength, and ultimate strain. Results show that shore hardness and infill density are the strongest predictors of mechanical properties, with positive but modest effects from anchor presence. Infill pattern is only significant through interactions, and its effects depend on other parameters. While all groups underperformed compared to manufacturer-reported TPU strengths and were well below in vitro tendon failure loads, findings highlight material selection and density optimization as critical early considerations for future patient-specific elastomeric graft design. Full article

The potential of elastomeric composites reinforced with natural fillers to replace traditional synthetic materials in applications involving exposure to acidic environments offers both economic and environmental advantages. On the one hand, these materials contribute to cost reduction and the valorization of organic waste through the development of value-added products. On the other hand, the presence of wood waste in the composite structure enhances biodegradation potential, making these materials less polluting and more consistent with the principles of the circular economy. The present study aims to evaluate the behavior of composites based on Ethylene Propylene Diene Monomer (EPDM) synthetic rubber, reinforced with silica and wood sawdust, in a weakly acidic yet strongly corrosive environment—specifically, acetic acid solutions with concentrations ranging from 10% to 30%. The study also investigates the extent to which varying the proportions of the two fillers affects the resistance of these materials under such environmental conditions. Physico-chemical, structural, and morphological analyses revealed that the materials underwent chemical modifications, such as acetylation of hydroxyl groups. This process reduced the hydrophilic character of the sawdust and, combined with the formation of stable interfaces between the elastomeric matrix and the fillers during vulcanization, limited acid penetration into the composite structure. The composites in which 20 phr or 30 phr of wood sawdust were used-replacing equivalent amounts of silica from the initial 50 phr formulation-demonstrated the highest resistance to the corrosive environments. After 14 days of exposure to a 20% acetic acid solution, the composite containing 30% wood sawdust exhibited a decrease in cross-link density of only 1.44%, accompanied by a reduction in Young’s modulus of just 0.95%. At the same time, tensile strength and specific elongation increased by 22.57% and 26.02%, respectively. FTIR and SEM analysis confirmed good rubber-filler interactions and the stability of the composite structure under acidic conditions. Full article