Search Results (669)

In recent years, new methods to reuse, repurpose, recycle, and recover decommissioned wind turbine blades (dWTBs) have actively been developed in the wind industry. In this study, the authors address the scientific challenge of repurposing decommissioned wind turbine blades for earthwork applications, particularly as part of retaining structures. A gravity retaining structure made entirely from recycled materials is introduced, consisting of glass fibre-reinforced polymer (GFRP) composite modular units derived from dWTBs. To improve the structure’s sustainability, a mixture of typical sand and lightweight waste materials is considered for filling and backfilling of the GFRP units. In particular, two waste materials are examined—a polymer foil derived from recycled laminated glass and tyre-derived aggregate (TDA) in the form of rubber powder—which are incorporated into the sand matrix in typical dry mass proportions ranging from 2% to 32% and 5% to 20%, respectively, reflecting practical ranges considered in geotechnical backfill applications. The research involved material testing of all recyclates and their mixtures with standard sand, as well as two-dimensional finite-element (2D FE) analysis of a retaining structure using the determined material properties. To facilitate the real-world implementation of this novel technology, a structure was designed to account for ground conditions at a specific site to protect against an existing landslide. In summary, this study presents the concept of a sustainable retaining structure along with results from material tests and an initial design for implementation, supported by FE analysis of overall stability. Full article

As the largest exporter in the global solid tire market, Sri Lanka’s natural rubber supply chain plays a critical role in global production, yet its social dimension remains largely unaddressed. Our study aims to assess the social performance of a Sri Lankan natural rubber supply chain in solid tire manufacturing using social life cycle assessment (S-LCA) in a cradle-to-gate approach. Study adapts “More Good and Less Bad” method which captures both positive and negative social impacts, addressing traditional S-LCAs’ focus on negative impacts solely. It applies to updated methodological sheets to distinguish “good” and “bad” social conditions across subcategories based on baseline compliance. Social impacts were quantified using a Social Performance Index (SPI), calculated by multiplying social performance levels by working hours at the organizational level, comprising SPI_good for good social impacts and SPI_bad for bad social impacts. Data was collected through stakeholder interviews, with working hours calculated using a “working hour model”. Results showed mixed social performance across 39 subcategories, identifying six social hotspots: promoting social responsibility (27.67% less bad, 72.32% more good), wealth distribution (26.87% less bad, 73.13% more good), commitment to sustainability issues (100% less bad), social benefits (100% less bad), safe and healthy living conditions (100% less bad), and hours of work (88.74% less bad, 11.26% more good). Full article

Aramid fiber is increasingly regarded as an important skeleton material in the conveyor belt industry. However, its application is limited by problems such as short splice service life and low strength retention. This study investigates the finger splice of an aramid rubber conveyor belt. A finite element model was established to analyze the effects of different rubber hardness values (60, 65, 70, 75), environmental temperatures (−20 to 40 °C), and finger widths (10 mm, 12 mm, 15 mm, 20 mm, 30 mm) on splice mechanical performance. The results show that the maximum stress is concentrated at the end surfaces of the reinforcement layer and the fingertips of the skeleton material. The splice strength increases with higher rubber hardness but decreases with rising environmental temperature. To improve splice strength, the rubber hardness and environmental temperature should be controlled within 60–70 and 0–20 °C, respectively. Although reducing finger width increases splice strength, excessively small widths lead to stress concentration and manufacturing difficulties. Therefore, finger width selection should consider actual working conditions. The experimental results are compared with simulation results, and the trend consistency verifies the correctness of the simulation. This study provides a theoretical basis for parameter selection and structural design of the splice under various working conditions. 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

Currently, large amounts of aggregate waste from the construction industry and ground tire rubber from the automotive sector are being generated. Enhancing and expanding recycling options for these materials is essential to support the transition toward a circular economy in both industries. This study proposes the use of recycled materials in the development of a seismic isolator designed for building partitions. As such, the new element must meet the performance requirements applicable to all materials used in building enclosures. Polyurethane is employed as a binder for the recycled components. The composite material is produced by combining polyurethane with varying proportions of recycled ground tire rubber and aggregates, expressed as a percentage of the polyurethane mass. The polyurethane is directly mixed with the recycled constituents. The resulting samples are subjected to thermal and acoustic testing to evaluate their suitability for partitions and enclosures in building construction in accordance with regulations. The results of the three tests indicate improvements in the measured properties, with the magnitude of enhancement depending on the ratio of ground tire rubber to aggregate. Overall, the developed composite materials exhibit characteristics and behavior compatible with the intended application. Full article

Although rubber waste devulcanization has been widely studied, its industrial-scale implementation remains limited due to challenges in process scalability. This study examines the feasibility of devulcanizing off-spec latex waste through a two-phase approach involving laboratory and pilot-scale trials. The latex waste was sourced from off-spec condom products composed of natural rubber latex. Laboratory-scale experiments were initially conducted to establish process parameters and generate baseline data, including gel content before and after the devulcanization process. Thermogravimetric analysis (TGA), gel permeation chromatography (GPC), and dynamic mechanical analysis (DMA) were employed. The laboratory findings have been used to design and operate the subsequent pilot-scale devulcanization process, using a retrofitted waste rubber machine. Samples from the pilot trials underwent the same analytical tests to assess consistency and process performance at scale. Results from the pilot scale experiments suggest that comparable levels of devulcanization were achieved, with gel contents of 52.5% and 55.2% achieved at the laboratory scale and pilot scale. GPC analysis confirmed a uniform distribution, with an increase in the number average molecular weight, indicating the scission of crosslinks in the sample. GPC analysis also revealed a decrease in dispersity index (Ð) value of 2.27 in lab scale conditions and 1.76 for pilot scale conditions, suggesting a more uniform molecular weight distribution and improved devulcanization efficiency, which enhances the possibility of recycling. The successful translation from lab-scale to the pilot setup highlights the process’s potential for industrial rubber recycling using retrofitted equipment. Full article

Silicone rubber from decommissioned composite insulators has become one of the major environmental challenges in the power industry due to its non-degradable nature. Therefore, the recycling and reuse of silicone rubber are of great environmental and economic significance. In this work, a method for preparing silica microspheres based on stepwise pyrolysis combined with post-treatment particle size fractionation is proposed. First, highly spherical silica microspheres were obtained by stepwise pyrolysis. Subsequently, glass fiber membrane filtration and aga-rose gel electrophoresis were employed as post-treatment methods to achieve particle size fractionation and enhanced uniformity. The results indicate that the post-treated silica microspheres exhibit high uniformity, high sphericity, and good dispersibility. This method significantly improves the structural uniformity and microscopic characteristics of the microspheres, making them promising high-value fillers for epoxy resin insulation modification. Comparative analysis with commercial nanosilica used as epoxy fillers shows that the recycled and fractionated silica microspheres achieve comparable improvements in breakdown strength and dielectric performance, confirming their potential for recycling and reuse in high-voltage insulation and electronic packaging applications. Full article

Magnetic soft manganese–zinc ferrite in a concentration scale ranging from 100 to 500 phr was incorporated into acrylonitrile-butadiene rubber. The work was focused on the investigation of manganese–zinc ferrite content on electromagnetic interference shielding effectiveness and mechanical properties of composites. The rubber-based products used in industrial practice should not only provide good utility and functional properties but should also exhibit good stability towards degradation factors, like oxygen and ozone. Therefore, the samples were exposed to the thermo-oxidative and ozone ageing conditions, and the influence of both factors on the composites’ properties was evaluated. The results demonstrated that the incorporation of ferrite into the rubber matrix resulted in the fabrication of composites with absorption-shielding performance. It was demonstrated that the higher the ferrite content, the lower the absorption-shielding ability. Electrical and thermal conductivity showed an increasing trend with increasing content of ferrite. On the other hand, the study of mechanical properties implied that ferrite acts as a non-reinforcing filler, leading to a decrease in tensile characteristics. Thermo-oxidative ageing tests revealed that ferrite, mainly in high amounts, could accelerate the degradation processes in composites. Though the absorption-shielding performance of composites after ageing corresponded to that of their equivalents before ageing, it can also be concluded that the higher the amount of ferrite in the rubber matrix, the lower the composites’ stability against ozone ageing. Full article

The increase in the viscosity of high-rubber-content asphalt modified with rubber powder at high temperatures leads to processing difficulties and drastic changes in physical properties, which have long been a challenge in the asphalt industry. Although viscosity reducers have shown great potential in addressing these issues, their mechanisms of action in high-rubber-content asphalt modified with rubber powder remain unclear. This study employs diphenyl disulfide (DD) as a viscosity reducer and elucidates its mechanism of action in high-rubber-content asphalt, which includes three stages: (1) dissolution and dispersion in the asphalt matrix; (2) impregnation into the crosslinked network of the rubber powder; and (3) de-crosslinking via active free radicals. By optimizing the pre-impregnation time (12 h), temperature (110 °C), and rubber powder particle size (160–180 µm), the dispersion of DD can be enhanced, thereby improving the processability of high-rubber-content asphalt modified with rubber powder. Compared to untreated asphalt, the optimized conditions result in a significant reduction in the crosslinking density of 50% and a substantial decrease in viscosity at 180 °C. This study provides new insights into the viscosity reduction of high-rubber-content asphalt modified with rubber powder and contributes to a deeper understanding of the mechanisms of viscosity reducers. Full article

The rubber industry uses phthalates as plasticizers in technical rubber goods due to their excellent compatibility, low volatility and cost-effectiveness. Growing concerns over their environmental and health impact have driven the search for sustainable alternatives. Bio-based plasticizers offer a promising solution due to their renewable nature, non-toxicity and biodegradability. This study explores the feasibility of replacing a conventional petroleum-based Di-Iso-Nonyl Phthalate (DINP) with a bio-based phthalate-free plasticizer, Aurora PHFree, in Nitrile Butadiene Rubber (NBR) compounds filled with semi-reinforcing carbon black N660. Aurora PHFree achieves similar processing behavior, cure characteristics, and mechanical properties as well as aging performance by using only half of the amount by weight of DINP. This efficiency is attributed to the improved plasticizing effects, which enable polymer chain mobility, without altering the overall crosslink density, as well as the enhanced dispersion of the carbon black (CB) fillers of the rubber compounds. This research supports the development of more sustainable rubber materials and contributes to reducing the dependence on fossil-based materials while maintaining high-quality standards. Full article

N-(1,3-Dimethylbutyl)-N’-phenyl-p-phenylenediamine (6PPD) is a member of the p-phenylenediamines (PPDs), recognized as a highly effective antioxidant. It has been extensively employed in the automotive tire manufacturing industry, and plays a critical role in enhancing the durability and service life of rubber materials. In recent years, significant research has demonstrated that 6PPD-quinone (6PPD-Q), the transformation product of 6PPD, is a toxic substance that causes the acute death of coho salmon (Oncorhynchus kisutch). The toxicity of its aquatic organisms has attracted great attention of scholars, and 6PPD-Q has been regarded as the emerging contaminant. It has been reported that 6PPD diffuses from rubber debris into environmental media such as air, soil, and water after the tires wear. 6PPD and 6PPD-Q have been widespread in the environment, and they migrate into food through the environment and enter the human body through exposure routes such as dietary intake and drinking water, posing potential risks to human health. This paper reviewed the current reports on the toxicity and health risks of 6PPD and 6PPD-Q, and compares the advantages and disadvantages of sample pretreatment methods and detection technologies of 6PPD and 6PPD-Q in different food matrices, and provides a scientific basis for food safety risk assessment. Evidence indicated that 6PPD-Q exhibits not only acute aquatic toxicity but also cytotoxicity, hepatotoxicity, neurotoxicity, and genotoxicity. Epidemiological data suggest a significant association between elevated 6PPD-Q levels and increased risks of colorectal cancer and liver abnormalities. There remains an urgent need to develop comprehensive, standardized, and high-throughput analytical methodologies for the efficient screening of 6PPD and 6PPD-Q in food samples, along with expanded dietary exposure assessments, to fully characterize the impacts of 6PPD and 6PPD-Q on human health. Full article

Rubber is a crucial sealing material in the petroleum industry. Due to increasingly stringent industrial development, safety performance requirements are becoming extremely high, resulting in higher oil resistance requirements for rubber. HNBR exhibits good heat resistance, high tensile strength, tear strength, and excellent wear resistance. However, a certain degree of aging will also occur in the actual service process, which will affect the service life of rubber. In order to explore the factors affecting the aging behavior of HNBR vulcanizates in an oil–water environment at 150 °C, HNBR vulcanizates were aged in an independent environment. IR (Infrared) spectroscopy analysis (FTIR), crosslinking density analysis, dynamic mechanical analysis (DMA), and scanning electron microscopy (SEM) testing were used to characterize the microstructural and morphological changes in HNBR vulcanizates before and after aging. The aging mechanism of HNBR vulcanizates in different environments was obtained. Since factors such as rubber fillers remained constant throughout the experimental process, the influence of formulation variables on aging was disregarded. Full article

Rubber materials are widely used in industrial sectors such as petrochemicals and energy due to their excellent elasticity, flexibility, and sealing properties. However, in complex and demanding service environments, rubber is susceptible to swelling or dissolution caused by medium corrosion, leading to seal failure or structural damage and ultimately resulting in safety incidents. To systematically review research progress and trends in this field, this paper employs 729 literature samples from the Web of Science core database (2008–2025) and utilizes VOSviewer and Citespace knowledge mapping tools to conduct a bibliometric analysis of corrosion research on rubber materials. This reveals existing knowledge gaps, technological challenges, hot trends, and future demands. Findings indicate that China, the United States, and India lead in publication volume. Research spans multiple disciplines including multidisciplinary materials science, applied physics, and polymer science, reflecting a cross-disciplinary nature. Current rubber corrosion studies focus on three key areas: fundamental properties and performance of rubber materials, corrosion mechanisms, and protective/corrosion-resistant technologies. Key international challenges include unclear mechanisms of complex media interactions, insufficient multi-scale characterization and life prediction, and limited adaptability to service environments. Future development trends will concentrate on three aspects: systematic research on novel multi-media coupling effects, precision in micro-mechanism and life prediction, and highly reliable advancement in green modification and high-performance protection. Full article

In light of the increasing demand for improved thermal performance within the tire industry, research on thermally conductive rubber composites has become a significant focus of interest. This paper provides a comprehensive overview of the most recent research findings on thermally conductive rubber composites, specifically for tire heat-dissipation applications. First, the thermal-conductivity mechanism of rubber-based composites is elaborated in detail, and the influencing factors of heat dissipation and thermal conductivity in tire rubber are systematically analyzed. The role of various thermally conductive fillers in tire heat dissipation and their applications is highlighted, and the thermal conductivities of these fillers and their effects in practical tire applications are compared. In addition, the distribution of fillers is optimized by combining experimental studies with simulation methods (e.g., molecular dynamics simulation) to provide a scientific basis for tire design. Finally, this paper summarizes the main challenges currently faced by rubber composites in tire applications, including material costs, filler and matrix dispersion, and thermal resistance. It also proposes the potential future development direction of thermally conductive rubber composites in tire applications. Full article

Precise monitoring of rubber plantations is critical for effective management and ecological assessments, enabling optimal resource allocation, disease detection, and mitigation of environmental impacts. This study integrated multi-source remote sensing data—including Landsat 8, Sentinel-1/2, GaoFen-1 (GF-1) optical and SAR imagery, and DEM data of Hainan Island. The rubber plantation areas from 2021 to 2025 were extracted from the Google Earth Engine (GEE) platform by employing a multi-step threshold segmentation method, which utilized the Otsu algorithm to automatically determine optimal thresholds for distinguishing rubber plantations from other land covers. The overall accuracy of the extracted rubber plantations in this study was above 90%; the Kappa coefficient was greater than 0.85; and the F1-score surpassed 0.93. The resulting distribution maps reveal that rubber plantations on Hainan Island are predominantly concentrated in the northwestern and northern regions. The rubber plantation area of Hainan Island remained relatively stable from 2021 to 2023. During 2023–2024, the rubber plantation area experienced a decline. This reduction was particularly pronounced in 2024, when the area decreased by nearly 150 km² compared to the previous year. However, in 2025, this downward trend reversed sharply with an increase of approximately 300 km². These findings provide a critical scientific basis for sustainable rubber production, supporting informed decision-making in irrigation, pest control, and yield optimization. Furthermore, they offer valuable insights for strategic planning to balance economic returns with ecological conservation, thereby ensuring the long-term viability of the industry. Full article