Search Results (138)

Devulcanization has the potential to help meet circular economy goals by recovering end-of-life rubber. However, the adoption of devulcanized rubber by manufacturers remains low at the industry level. Devulcanization value chains are complex and involve multiple stakeholders, including waste collectors, sorters, recyclers, compounders, manufacturers and regulatory bodies. This study investigated the barriers compounders and manufacturers face when incorporating devulcanized rubber into new compounds and identified primary underlying causes. The research was conducted through in-depth interviews with compounders and manufacturers of tires and general rubber goods, focusing on the technical, market, institutional, and cultural factors related to incorporating recycled materials, specifically devulcanized rubber. From the results, we identified a number of barriers faced by the industry. A key barrier was the heterogeneity of devulcanized rubber, which made it more difficult to add to new rubber compounds with consistent quality. Other barriers included a lack of standardization and coordination, along with misaligned regulations that hamper the market adoption of devulcanized rubber. This implies that increasing the uptake of devulcanized rubber at the industry level will not be achieved through technological advancements alone or isolated market interventions; instead, it requires comprehensive, systemic solutions. Full article

Tire shape prediction presents significant engineering challenges due to the complex behavior of cord-rubber composites during manufacturing processes. Fabric cord components undergo thermal shrinkage and permanent deformation that substantially influence final tire dimensions, creating discrepancies between mold geometry and cured tire shape. While Post-Cure Inflation (PCI) helps control these dimensional changes, accurate prediction methods remain essential for reliable performance forecasting. This study addresses this challenge through a systematic experimental characterization of fabric cord behavior under manufacturing conditions. Thermal shrinkage and permanent set were quantified under various combinations of in-mold strain and PCI force, with distinct patterns identified for different cord materials (PET and nylon). Based on these experimental findings, a comprehensive finite element analysis methodology was developed to predict cured tire shape. Validation against 65 tire profiles demonstrated remarkable improvements over conventional approaches, with dimensional error reductions of 54.2% for the outer diameter and 49.5% for the section width. Profile and footprint predictions also showed significantly enhanced accuracy, particularly in capturing geometric features critical for tire–road contact characteristics. The proposed methodology enables more precise tire design optimization, improved performance prediction, and reduced prototype iterations, ultimately enhancing both product development efficiency and final tire performance. Full article

This work presents a novel fully automated computational framework for optimizing profile extrusion dies, aiming to achieve balanced flow at the die flow channel outlet while minimizing total pressure drop. The framework integrates non-isothermal, non-Newtonian flow modeling in OpenFOAM with a geometry parameterization routine in FreeCAD and a Bayesian optimization algorithm from Scikit-Optimize. A custom solver was developed to account for temperature-dependent viscosity using the Bird–Carreau–Arrhenius model, incorporating viscous dissipation and a novel boundary condition to replicate the thermal regulation used in the experimental process. For optimization, the die flow channel outlet cross-section is discretized into elemental sections, enabling localized flow analysis and establishing a convergence criterion based on the total objective function value. A case study on a tire tread die demonstrates the framework’s ability to iteratively refine internal geometry by adjusting key design parameters, resulting in significant improvements in outlet velocity uniformity and reduced pressure drop. Within the searching space, the results showed an optimal objective function of 0.2001 for the best configuration, compared to 0.7333 for the worst configuration, representing an enhancement of 72.7%. The results validate the effectiveness of the proposed framework in navigating complex design spaces with minimal manual input, offering a robust and generalizable approach to extrusion die optimization. This methodology enhances process efficiency, reduces development time, and improves final product quality, particularly for complex and asymmetric die geometries commonly found in the automotive and tire manufacturing industries. Full article

Natural rubber is a widely used biological polymer material because of its excellent comprehensive performance. Nevertheless, the performance of domestic natural rubber cannot meet the requirements for high-end products such as aviation tires, which has become a constraint on the innovation and upgrading of high-end manufacturing enterprises and the enhancement of global competitiveness in China. To solve the bottleneck problem of natural rubber processing technology, this study systematically analyzed the effects of different varieties of fresh latex ratios on the processing and dynamic properties of bio-coagulated natural rubber. By mixing PR107 and Reyan72059 fresh latex with Reyan73397 fresh latex according to proportion, the fresh latex was coagulated by enzyme-assisted microbials, and the effects of the fresh latex ratio on physical and chemical indexes, molecular weight distribution, vulcanization characteristics, processing properties, cross-link density and physical and mechanical properties of the natural rubber were analyzed. The results showed that the aging resistance of natural rubber coagulated with enzyme-assisted microbial decreased, and the aging resistance of natural rubber increased with the increase in the mixing ratio of PR107 and Reyan72059 fresh latex. The proportion of high molecular weight of the natural rubber coagulated with the enzyme-assisted microbial increased, and the fresh latex mixing had little effect on the molecular weight distribution curve. Under the carbon black formulation, the CRI of the enzyme-assisted microbial coagulated natural rubber compound was relatively larger. Under the same strain conditions, the H-3 compound (PR107:Reyan72059:Reyan73397 = 1:1:3) had the best viscoelasticity and the least internal resistance of rubber molecules. In addition, the cross-link density, tensile strength, elongation at break, and tear strength of H-3 vulcanized rubber were the largest, improved by 23.08%, 5.32%, 12.45% and 3.70% compared with the same H-2 vulcanized rubber. In addition, the heat generation performance was reduced by 11.86%, and the wear resistance improved. Full article

Various stabilizers, such as jute, gypsum, rice-husk ash, fly ash, cement, lime, and discarded rubber tires, are commonly used to improve the shear strength and overall characteristics of clay subgrade soil. In this study, waste foundry sand (WFS) is utilized as a stabilizing material to enhance the properties of clay subgrade soil and strengthen the bond between clay subgrade soil and subbase material. The materials employed in this study include Type B subbase granular materials, clay subgrade soil, and 1100 Biaxial Geogrid for reinforcement. The clay subgrade soil was collected from the airport area in the Al-Muthanna region of Baghdad. To evaluate the effectiveness of WFS as a stabilizer, soil specimens were prepared with varying replacement levels of 0%, 5%, 10%, and 15%. This study conducted a Modified Proctor Test, a California Bearing Ratio test, and a large-scale direct shear test to determine key parameters, including the CBR value, maximum dry density, optimum moisture content, and the compressive strength of the soil mixture. A specially designed large-scale direct shear apparatus was manufactured and utilized for testing, which comprised an upper square box measuring 20 cm × 20 cm × 10 cm and a lower rectangular box with dimensions of 200 mm × 250 mm × 100 mm. The findings indicate that the interface shear strength and overall properties of the clay subgrade soil improve as the proportion of WFS increases. Full article

This review explores the evolving landscape of sustainable textile manufacturing, with a focus on rubber-based materials for various industrial applications. The textile and rubber industries are shifting towards eco-friendly practices, driven by environmental concerns and the need to reduce carbon footprints. The integration of sustainable textiles in rubber-based products, such as tires, conveyor belts, and defense products, is becoming increasingly prominent. This review discusses the adoption of natural fibers like flax, jute, and hemp, which offer biodegradability and improved mechanical properties. Additionally, it highlights sustainable elastomer sources, including natural rubber from Hevea brasiliensis and alternative plants like Guayule and Russian dandelion, as well as bio-based synthetic rubbers derived from terpenes and biomass. The review also covers sustainable additives, such as silica fillers, nanoclay, and bio-based plasticizers, which enhance performance while reducing environmental impact. Textile–rubber composites offer a cost-effective alternative to traditional fiber-reinforced polymers when high flexibility and impact resistance are needed. Rubber matrices enhance fatigue life under cyclic loading, and sustainable textiles like jute can reduce environmental impact. The manufacturing process involves rubber preparation, composite assembly, consolidation/curing, and post-processing, with precise control over temperature and pressure during curing being critical. These composites are versatile and robust, finding applications in tires, conveyor belts, insulation, and more. The review also highlights the advantages of textile–rubber composites, innovative recycling and upcycling initiatives, addressing current challenges and outlining future perspectives for achieving a circular economy in the textile and rubber sectors. Full article

The cement industry contributes approximately 7% of global anthropogenic CO₂ emissions, primarily through energy-intensive clinker production. This study evaluates the thermal behavior and gas emissions of seven waste materials (sawdust, pecan nutshell, wind blade waste, industrial hose waste, tire-derived fuel, plastic waste, and automotive shredder residue) as alternative fuels for cement manufacturing, motivated by the limited information available regarding their performance and environmental impact, with bituminous coal used as a reference. Thermogravimetric analysis and differential scanning calorimetry (TGA-DSC) were used to quantify mass loss and energy changes, while TGA coupled with mass spectrometry (TGA-MS) was used to identify volatile compounds released during thermal degradation. Both TGA-DSC and TGA-MS were conducted under oxidative conditions. The analysis revealed that these waste materials can generate up to 70% of coal’s energy, with combustion primarily occurring between 200 °C and 600 °C. The thermal profiles demonstrated that these materials can effectively replace fossil fuels without releasing harmful toxic gases like HCl, dioxins, or furans. Combustion predominantly emitted CO₂ and H₂O, with only trace volatile organic compounds such as C₃H₃ and COOH. The findings highlight the potential of alternative fuels to provide substantial energy for cement production while addressing waste management challenges and reducing the industry’s environmental impact through innovative resource valorization. Full article

The adhesion between rubber compounds and textile cords plays a critical role in determining the overall performance and durability of rubber-based composites, particularly in tire applications. Despite extensive research on adhesion mechanisms, optimizing adhesion through systematic modeling remains challenging due to the complex interactions between rubber formulations, textile treatment, and processing conditions. This study presents an integrated experimental and predictive modeling approach to investigate and optimize the adhesion performance of nylon 6.6 textile cords in rubber compounds. Initially, the effects of different accelerator types—including diphenyl guanidine (DPG), 2,2′-Dithiobis(benzothiazole) (MBTS), N-tert-butyl-2-benzothiazole sulfenamide (TBBS), and N-cyclohexyl-2-benzothiazole sulfenamide (CBS)—on adhesion properties were systematically evaluated. Key parameters such as cure characteristics, Mooney viscosity, and mechanical properties of the rubber compounds were analyzed using a moving die rheometer (MDR), Mooney viscometer, and tensometer. To enhance adhesion performance, a statistical optimization approach based on the Box–Behnken design was employed, focusing on the influence of accelerator, curing agent, and resin contents. The results indicate that an optimized rubber formulation comprising 1.6 phr curing agent, 0.3 phr resin (HMMM), and 0.5 phr accelerator (MBTS) yields the highest adhesion strength. This study provides the first systematic modeling of adhesion between nylon 6.6 textile cords and rubber compounds using response surface methodology (RSM), offering valuable insights into the material design for improved interfacial bonding in tire manufacturing. Full article

The aim of this study is to investigate the potential of wood composites as sustainable acoustic materials and to explore their integration with advanced manufacturing techniques for improved performance. Using a comprehensive review methodology, the paper analyzes recent innovations in wood composites, focusing on the combination with other sustainable materials such as expanded polystyrene (EPS) and natural fibers. The results show that wood composites can achieve sound absorption coefficients (α) of up to 0.9, with oak panels showing transmission losses of up to 11 dB. In addition, advanced designs, including biodegradable panels and lightweight honeycomb structures, significantly improve sound transmission loss, with an average sound transmission loss (TLeq) of up to 28.3 dB reported for composite panels made from waste tire rubber. In addition, the study highlights the environmental benefits achieved through the use of agricultural byproducts and industrial waste in the development of these materials, confirming the role of wood composites as a carbon-neutral alternative in the quest for green building solutions. This study provides valuable insights into the transformative potential of wood composites for sustainable acoustic applications. Full article

The aim of the article was to test new types of rubber-containing particleboards created from waste materials, which positively contributes to environmental protection, saving primary resources and reducing production costs. This article focuses on the study of three-layer particleboards made from wood particles (spruce non-treated beams) and waste rubber granulates (tires, mixture of seals and carpets, internal flammable cables, external non-flammable cables). Urea–formaldehyde glue, melamine–formaldehyde glue, paraffin emulsion, and ammonium nitrate were used as a binders and excipients in the manufacturing of particleboards. In the core layer of each particleboard, 10% of the weight was made up of rubber granulate. Physical properties (density, water absorption, thickness swelling) and mechanical properties (internal bonding strength, modulus of rupture, modulus of elasticity, screw driving torque) were assessed from this perspective using current EN technical standards. According to the findings, the average densities of all particleboards were comparable to each other in a range from 0.692 to 0.704 g·cm⁻³. The lowest average water absorption and thickness swelling reached particleboards containing 10% of waste internal flammable cables, namely 32.79% for water absorption and 13.21% for thickness swelling. The highest average internal bonding strength reached particleboards without rubber filler and particleboards containing 10% of waste external non-flammable cables, namely 0.52 MPa for both types. The highest average modulus of rupture reached particleboards without rubber filler, namely 12.44 MPa. The highest average modulus of elasticity reached particleboards containing 10% of waste internal flammable cables, namely 2206.29 MPa, and the highest screw driving torque reached particleboards without rubber filler, namely 0.46 N·m for seating torque and 1.44 N·m for stripping torque. The results show that particleboards containing waste external non-flammable cables and particleboards containing waste internal flammable cables achieved comparable results to particleboards without rubber filler, which provides a good basis for a new way of utilizing this type of waste in the form of producing new wood–rubber composites. Full article

In recent years, non-pneumatic tires have been gaining popularity, which can be seen in the increase in research results and proposals from world-class tire manufacturers (mainly as technology demonstrators). The possibility of eliminating the need to maintain compressed air is a major factor in the development of non-pneumatic tires and their usage in vehicles. Articles and patents were reviewed in relation to the load transfer mechanism, the design of non-pneumatic tire components, and recommendations for materials. Non-pneumatic tire top loaders are a desirable type of this type of wheel compared to bottom loaders, because they transfer loads over a larger part of the wheel, which increases their load capacity. Most non-pneumatic tires consist of a rim, an elastic structure, and a shear beam/band with a tread. The rim is used to secure the elastic structure and can be fitted with vibration dampers in the form of circumferential rubber rings. The gradient elastic structure, in comparison with the homogeneous structure (same thickness or dimensions of the elements), allows the range of axle displacements to be adjusted to the desired level without the need to increase the size of the wheel, and also influences the change in the location of the maximum stresses. The shear beam/ band mimics the properties of compressed air used in pneumatic tires. The shear beam/ band made as a webbing geometry ensures uniform pressure in the contact patch. The reinforced composite shear beam/ band ensures adequate bending strength with low energy losses and a small thickness of the beam/ band. Materials commonly used in the tire industry are used as reinforcement for the shear beam/ band, which was illustrated by the results of our own research. Full article

In the tire manufacturing process, rubber compounds are vulcanized in volcanic presses. The vulcanization technology is carried out at temperatures above 150 °C, i.e., at a temperature potential that causes heat losses if the containers are not sufficiently insulated. The paper describes the mathematical model developed to detect the heat fluxes from the container walls to the surroundings. The calculation is carried out strictly in the SI system. With the help of the developed model, the back-relations of heat losses through the vertical and horizontal walls of the container enclosure were obtained as a function of the thickness of the insulation without and with a radiation shield on the inside of the enclosure. Numerical modeling using the finite volume method was used to verify the results obtained. In the numerical simulation, a 2D and a 3D model were created, and the same input conditions as in the mathematical model were simulated. Using the obtained results, an energy-energy balance of the tire vulcanization technology was performed by comparing the heat loss fraction as a function of the external temperature of the container cover and as a function of the insulation thickness. Full article

Tire puncturing is one of the main causes of accidents and/or traffic interruptions, leading to unsafe and unsustainable mobility scenarios. Insert-supporting Run-Flat systems can be a strategic technology to improve tire performance, but further developments are needed to improve system reliability, modularity, and efficiency. A novel Run-Flat system was proposed in the present study to address specific features. The concept was developed by exploiting numerical simulation tools, enabling a comprehensive system assessment. In addition, a technological demonstrator was manufactured employing rapid prototyping techniques based on 3D printing processes. Full article

A demand to replace an easily combustible wood with wood–plastic–rubber composite with better thermal performance than wood is at its peak globally. Wood-based composite materials in the form of wood–polymer composite (WPC) have emerged as new materials that can replace wood to produce wood products for various use. The use of recycled polymers as biodegradable polymer blended with fiber particles, waste tire powder, and other substances to manufacture new products known as wood–rubber–plastics composite (WRPC) for building construction and other different applications, has piqued the interest of numerous researchers. High flammability and weak combustibility parameters are a setback for many wood-based composites because of the flammability of these composites. Fabricated WRPC based on non-toxic fire retardants and other additives used to modify the flame-resistant quality of these composites, the fabrication techniques, and mechanical characteristics are herein reviewed. It is hoped that better composite in the form of WRPC can be used as building materials for informal and formal dwellings. Full article

Currently, the disposal of waste tires is considered one of the priority environmental and public health problems worldwide. Every year, more than 1.4 billion unused tires are placed in landfills. Population growth, economic development, and a strong demand for vehicle production in the automotive industry increase this problem. In Mexico, nearly 36 million unused tires are deposited in landfills or clandestine deposits, the vast majority being burned or accumulated in the open air. The lack of regulations in the handling, disposal, and recycling of tires creates a worrying panorama for environmental care and the problems that this entails. The objective of this work is to propose a viable alternative for the final disposal and recycling of waste tires through the implementation of a company for the manufacture of products based on recycled rubber in the state of Tamaulipas, Mexico, reducing environmental pollution by these wastes and generating sources of employment through a sustainable company. For this purpose, a study was carried out in Tamaulipas, Mexico, through surveys to determine the number of tires that can be obtained and determine the feasibility of the business; subsequently, a prediction was made using simulation software to design and estimate the expected production in the manufacture of parking bumpers using two scenarios with two and four workers. Likewise, specialized software was used to optimize waste tire collection routes from the different tire stores to the company’s location. The results show that with an optimal design of the tire collection routes, up to 483 tons of waste tires can be recovered per year, representing 10% of the total unused tires in Tamaulipas. Because it is an environmental and social problem, installing a company manufacturing products based on recycled rubber is feasible and has a high probability of success for the region studied. According to the simulation, employing four workers increases productivity and decreases manufacturing costs. Through the simulation, three tire collection routes were determined considering the total number of tire stores in the city where the company is located. Full article