Rubber Materials Research Articles

FUNDAMENTAL APPROACH TO PREDICT TIRE AIR PRESSURE LOSS OVER TIME

ABSTRACT Rubber material used in consumer products is vulcanized to improve its strength, viscoelasticity, and long and short-term durability. During the cure process, the morphology of the material evolves to form a highly crosslinked chain network, leading to a product that is less porous and less susceptible to air diffusivity. However, the formulation of the rubber compounds always create micropores or voids within them. Several laboratory tests are used to measure the material’s ability to resist the flow of air through it and to assess its porosity, especially under pressure. Residual-based integrated surface flux calculations are used to determine the evolution of air pressure as a function of time in an enclosed volume such as the cavity of an inflated tire. A finite element formulation was established for complex applications such as tires to predict the intracarcass pressure distribution. The capability of this simulation methodology was demonstrated for a tire with different inner liner compositions.

Research on rubber classification and recognition based on terahertz time-domain spectroscopy and improved honey badger algorithm

The identification of different rubber materials is crucial to ensuring the quality of rubber products. In order to quickly and effectively identify the types of rubber, reduce the impact of counterfeit rubber on the market. This study proposes a rubber identification method based on terahertz time-domain spectroscopy (THz-TDS), Chemometry, and Improved Honey Badger Algorithm (IHBA). Initially, the absorption spectra of eight types of rubber within the 0.2–1.6 THz range are obtained and calculated using THz-TDS. This is followed by data preprocessing using Savitzky-Golay and Principal component analysis(PCA). The optimization effects of genetic algorithm (GA), grid optimization algorithm (GRID), particle swarm optimization algorithm (PSO) and honey badger algorithm (HBA) on support vector machine (SVM) model parameters were compared respectively. The HBA-SVM model achieves 96.88 % recognition accuracy on the prediction set, which is higher than other models and shows excellent parameter optimization ability.To further improve accuracy, Bernoulli chaotic mapping, cosine density factor, and Cauchy mutation are introduced for improvement. Compared with the original model, the IHBA-SVM model improves the accuracy of rubber recognition from 96.88 % to 98.96 %. Furthermore, compared with other models, the IHBA-SVM model achieved the highest classification accuracy. In summary, this study provides technical support and reference for the rapid identification of rubber, which is of great significance for ensuring the quality of rubber products.

The Benefits of Using Rubber Material in Two Variances: The Rubberized Concrete and the Natural Rubber Sheet, to Strengthen Concrete Barriers for Crash Energy Absorption

The Benefits of Using Rubber Material in Two Variances: The Rubberized Concrete and the Natural Rubber Sheet, to Strengthen Concrete Barriers for Crash Energy Absorption

Granulated rubber in playgrounds and sports fields: A potential source of atmospheric plastic-related contaminants and plastic additives after runoff events

The use of “crumb rubber” coming from recycling materials in outdoor floors like playgrounds has been a frequent practice during the last years. However, these surfaces are object of abrasion and weathering being a potential source of micro and nanoplastics (MNPLs) to the atmosphere and a potential source of human exposure to them. Our main goal has been to expose different crumb rubber materials to summer weathering effects. The released inhalable fractions were sampled for two months with passive samplers and the composition of MNPLs and plastic additives (organic and inorganic) were evaluated. The ecotoxicological effects of leached materials emulating runoff events was evaluated in freshwater micro crustacean Daphnia magna and the green algae Chlorella vulgaris. The analysis of MNPLs showed the presence of polyethylene, polypropylene, polybutadiene, polysiloxanes and polybutylene at concentrations up to 30,426 ng/m3. In the same fraction, we also identified up to 56 plastic additives, including antioxidants, pigments, copolymers, flame retardants, fungicides, lubricants, plasticizers, UV filters and metal ions. Finally, runoff ecotoxicological effects on D. magna and C. vulgaris showed that leached compounds, either from virgin or aged material, would be toxicants for exposed organisms although at concentrations much higher than those expected to be released to the media.

Recent Advances in Fire-Retardant Silicone Rubber Composites.

Silicone rubber (SR), as one kind of highly valuable rubber material, has been widely used in many fields, e.g., construction, transportation, the electronics industry, automobiles, aviation, and biology, owing to its attractive properties, including high- and low-temperature resistance, weathering resistance, chemical stability, and electrical isolation, as well as transparency. Unfortunately, the inherent flammability of SR largely restricts its practical application in many fields that have high standard requirements for flame retardancy. Throughout the last decade, a series of flame-retardant strategies have been adopted which enhance the flame retardancy of SR and even enhance its other key properties, such as mechanical properties and thermal stability. This comprehensive review systematically reviewed the recent research advances in flame-retarded SR materials and summarized and introduced the up-to-date design of different types of flame retardants and their effects on flame-retardant properties and other performances of SR. In addition, the related flame-retardant mechanisms of the as-prepared flame-retardant SR materials are analyzed and presented. Moreover, key challenges associated with these various types of FRs are discussed, and future development directions are also proposed.

An overview of patents of noise reduction in buildings

Noise is an unwanted sound in urban areas. Natural and or recycled acoustic absorbing or insulation materials are invented to reduce air and or impact sounds in buildings. Yet, they are not widely and commercially available. This review presented an overview of relevant studies on natural materials particularly on cotton and rubber using Scopus search engine and of the patents registered and granted using Espacenet and Google Patents search engines on noise reduction in buildings from the years 1996 to 2023. The 18% and 68% (out of 32 articles) relevant articles, respectively, were written on cotton and rubber and other recycled natural material e.g., consumed teabags, rubber crumb, indicating a clear vision for experimentation and modeling of natural materials e.g., to investigate their sound absorption coefficients at lower frequencies (below 250 Hz) for (recycled) cotton sound absorbing materials and for producing ultralight density with high sound absorption materials (0.56) using recycled rubber material. There were found 31 patents registered and granted, in total. Natural materials, namely, cotton, rubber, glass wool and rock wool were applied in 29% of patents registered and granted from 1996 to 2022. Yet, 93% of patents registered and granted lacked data on sound absorption index of materials they invented. LDA models estimated 29% of Espacenet and Google Patents patents registered and granted having an increased trend of patent innovations for example, in method, structure and building materials in the last decade.

Structural Improvement in Crane Boom Rest

Crane boom rests are critical components that endure both static and dynamic loads, leading to deformation and a shortened lifespan. This paper addresses these issues by proposing a redesigned model with enhanced stiffness and load-bearing capacity. The new design incorporates gussets and Styrene-Butadiene Rubber (SBR) sheets. A series of trials were conducted to analyze various stiffener configurations, with results showing a significant reduction in deformation. The optimal configuration, consisting of three L-shaped stiffeners placed at specific intervals, reduced deformation from 17.2 mm to 2.2 mm. Additionally , the integration of SBR rubber sheets further minimized deformation to 0.15 mm. These modifications demonstrate the effectiveness of the proposed improvements in enhancing the durability and performance of crane boom rests. The findings provide a robust solution for extending the operational life of crane boom rests under dynamic loading conditions. Future research can explore different rubber materials and stiffener designs to further enhance structural integrity and load-bearing capacity.

Structural Improvement in Crane Boom Rest

Crane boom rests are critical components that endure both static and dynamic loads, leading to deformation and a shortened lifespan. This paper addresses these issues by proposing a redesigned model with enhanced stiffness and load-bearing capacity. The new design incorporates gussets and Styrene-Butadiene Rubber (SBR) sheets. A series of trials were conducted to analyze various stiffener configurations, with results showing a significant reduction in deformation. The optimal configuration, consisting of three L-shaped stiffeners placed at specific intervals, reduced deformation from 17.2 mm to 2.2 mm. Additionally , the integration of SBR rubber sheets further minimized deformation to 0.15 mm. These modifications demonstrate the effectiveness of the proposed improvements in enhancing the durability and performance of crane boom rests. The findings provide a robust solution for extending the operational life of crane boom rests under dynamic loading conditions. Future research can explore different rubber materials and stiffener designs to further enhance structural integrity and load-bearing capacity.

Hydrogen permeation behavior and mechanisms in nitrile butadiene rubber composites for hydrogen sealing

As the most widely used sealing component in hydrogen systems, rubber seals are affected by hydrogen over long-term service. Hydrogen molecules can dissolve into rubber materials and diffuse through the material. Studies have shown that adding fillers can enhance rubber's performance, improve its compatibility with hydrogen, and reduce the damage caused by hydrogen diffusion. Therefore, this study integrates experimental hydrogen permeation research with finite element modeling for nitrile butadiene rubber (NBR). The aim is to investigate the influence of filler properties on the microstructure, hydrogen permeation behavior, and hydrogen concentration distribution within NBR. Ultimately, the study elucidates the mechanisms governing hydrogen distribution evolution and permeation in NBR under hydrogen environments. The results indicate that the crosslink density of NBR filled with carbon black (NBR-CB) and silica (NBR-SC) is directly proportional to the filler content. NBR with higher filler content exhibits a lower hydrogen permeation coefficient and superior hydrogen barrier properties. In contrast to silica fillers, carbon black fillers demonstrate strong adsorption and a more pronounced barrier effect against hydrogen molecules, thereby enhancing the hydrogen barrier efficiency. The increase in carbon black's hydrogen solubility (from 2.2 × 10-4 to 16.9 × 10-4 cc(STP)·cm-3(polymer)·cmHg-1) effectively reduces the hydrogen permeation coefficient. In contrast, the rise in carbon black's hydrogen diffusion coefficient (from 0.1 × 10-6 to 4.1 × 10-6 cm2·s-1) exacerbates the overall hydrogen permeation coefficient of NBR-CB, thereby intensifying the hydrogen permeation process.

Aging assessment of silicone rubber materials under corona discharge accompanied by humidity and UV radiation

Abstract High voltage (HV) outdoor insulators are subjected to both electrical and environmental stresses, which may lead to their failure. Among the causes, corona discharge, humidity and UV radiation are considered to be the most damaging factors. Efforts are therefore underway to investigate new materials for improving the performance of insulating systems. In this research work, silicone-based room temperature vulcanized samples filled with alumina trihydrate (ATH), silicon dioxide and magnesium hydroxide (MH) were prepared and exposed to AC corona discharge for a duration of 110 h. The electric discharge was also accompanied by UV radiation and two different humidity levels. Following aging of the test samples, diagnosis was conducted to assess their integrity. Measurements based on determining the static contact angle demonstrated the loss of hydrophobicity of all the materials, while hydrophobicity recovery phenomena revealed that ATH-doped materials demonstrated a comparatively higher increase in the contact angle than in samples filled with silicone dioxide (silica) and MH. Scanning electron microscopy analysis revealed deep cracks and block-like structures on their surfaces. Similarly, energy-dispersive X-ray analysis indicated the signs of surface oxidation of the aged samples. However, the data of elemental composition exhibited the loss of filler contents as well as that of carbon from the base matrix. The overall assessment showed that resistance to suppress aging is influenced by both the filler type and its concentration in the investigated composites. The ATH-filled composites exhibited outstanding performance when exposed to the rigors of corona discharge and other environmental stresses. This research contributes to materials science and HV engineering by addressing the development of composites for enhanced insulator performance, with future aspects lying in the utilization of nano-composites for advanced functionality and durability.

Fatigue Life Prediction of a Rubber Mount Considering the Self-Heating by the Hysteresis Loss of the Rubber Material Subjected to Cyclic Loadings

Failure analysis and fatigue life prediction are important steps in the design procedure of industrial products to assure the safety and reliability of their components. A model to calculate the heat generation by the hysteresis loss in natural rubber subjected to cyclic loads in a uniaxial direction was introduced and the fatigue life prediction model of the rubber was established based on the theory of continuum damage mechanics (CDM). Dynamic mechanical analysis (DMA) was used to measure the viscoelasticity of the rubber material. The heat generation in the rubber material was calculated using a subroutine with the programming software C++ and the temperature rise in the rubber material was analyzed by a thermal finite element analysis (FEA) method. Then static mechanical FEA models of a rubber mount were established and the strain contours of the rubber mounts at various loads were calculated. The total principal strain was used as the fatigue parameter to predict the fatigue life of the rubber mount. Finally, the fatigue lives of the rubber mounts at various loads were measured on a test rig to validate the accuracy of the prediction method. The test results indicated that the fatigue lives predicted considering the temperature rise agreed better with the test results compared with those not considering the temperature rise and we suggest our fatigue prediction method should be applicable to both rubber and other types of components.

Modulation of Mechanical Properties of Silica-Filled Silicone Rubber by Cross-Linked Network Structure.

Associating molecular structure and mechanical properties is important for silicone rubber design. Although silicone rubbers are widely used due to their odourless, non-toxic, and high- and low-temperature resistance advantages, their application and development are still limited by their poor mechanical properties. The mechanical properties of silicone rubbers can be regulated by designing the cross-link density and cross-linking structure, and altering the molar contents of vinyl in the side groups of methyl vinyl silicone rubber (MVQ) leads to different cross-linking structures and cross-linking densities in the vulcanized rubber. Therefore, this study investigated the differences in molecular parameters and molecular chain structures of unprocessed MVQ rubbers with different vinyl contents. The results showed that MVQ rubbers with high vinyl contents were branched polymers, better facilitating the cross-linking reaction than MVQ rubbers with low vinyl contents. In addition, silicone rubbers with different vinyl contents were co-cross-linked to introduce an inhomogeneous cross-linked network in the silicone rubber to improve its mechanical properties. The cross-linked network properties were analysed by the Flory-Rehner model and Mooney-Rivlin plots, and it was found that the long chains in the sparsely cross-linked domains of the network favoured high elongation at break and the short chains in the densely cross-linked domains contributed to high modulus, which could satisfy the functions of reinforcing and toughening the rubber materials at the same time. It was also found by analysing the filler network and aggregate morphology that the inhomogeneous cross-linked network led to an improvement in the dispersion of silica in the rubber and a significant improvement in the mechanical properties of silicone rubber.

KAJI NUMERIK GROUND PAD SHOE KENDARAAN TEMPUR DENGAN MODEL MATERIAL HYPERELASTIC

One of the important components on a combat vehicle is the ground pad shoe (GPS) or track pad. GPS that has been developed at this time mostly uses rubber material. Rubber raw materials themselves are found in Indonesia in large amount. Indonesia left 3 million tonnes of natural rubber unprocessed in 2018. On the other hand, natural rubber research is quite expensive and takes a long time to become a product. To make rubber products is needed special molds and tests. To solve the high costs and long time involved in rubber research, it is necessary to carry out numerical research. In this study, a numerical study of GPS rubber for combat vehicles was carried out with a hyperelastic material model. The research was conducted experimentally and numerically. Tensile testing is carried out on imported GPS samples which are then used as comparison data for numerical studies. The Mooney-Rivlin, Neo-Hookean, Yeoh, and Ogden hyperelastic models were varied to get the stress and strain values ​​closest to the experimental test. The results of the numerical study show that the best hyperelastic model for the imported GPS rubber model is the Neo-Hookean model. The tensile strength of GPS according to the experimental tensile test results is 16.93 MPa, while the result of the finite element method (FEM) is 16.75 MPa. The GPS modulus 200% according to the experimental tensile test results is 14.7 mm/mm, while the FEM result is 15.3 mm/mm. The difference between the FEM and experimental test values ​​for tensile strength and modulus 200% are below 5%. Maximum stress on GPS is 4,4 MPa and safety factor 3,8.

Contrastive loss with dynamic margin for rubber-recipe physical-property prediction

Predicting the physical properties of rubber presents difficulties because of the intricate and nonlinear relationships between its constituent elements. The laborious nature of rubber manufacture results in restricted data sets, hence exacerbating this difficulty. To achieve successful training of a neural network with a smaller amount of data, it is crucial to use an appropriate weight initialization approach and carefully construct the network architecture to avoid overfitting. This study presents a novel approach to representation learning that uses a contrastive loss with dynamic margin loss function. The approach is specifically designed to capture semantic similarities in rubber material quantities and physical-property recipes. In addition, a novel neural network architecture is proposed that uses latent vectors for assigning initial weights. The proposed approach, validated using data from a rubber manufacturing company, showed a significant improvement of up to 30% in predictive accuracy for physical properties with a restricted amount of data.

Numerical Study of Tangential Traction Mechanism between Pattern Blocks of Agricultural Radial Tires and Soft Soil.

With the increasing requirements of agricultural machinery, the study of the contact relationship between the tire-soil interface and the improvement of traction efficiency has gradually become a main concern. In this study, the pattern on the agricultural tire was simplified into single-pitch pattern blocks. The pattern blocks were made of rubber material that was highly resistant to abrasion and bending. The experiment was carried out by pressing the three types of patterned block construction into the soil and the pure sliding under the soil. The simulation used the Coupled Eulerian-Lagrangian Method (CEL) to verify the experimental results. We found that the herringbone pattern block was subjected to the highest stress for the same depth of downward pressure. The horizontal force generated by the pure sliding was also the highest. The results showed that the numerically simulated and experimentally measured data exhibited similar trends and average values. In addition, the increase in the contact area between the tire and the soil reduced the compaction and sinking of the soil. The herringbone pattern structure not only had a large contact area but also produced the most significant shear force on the soil. Thus, it may generate greater traction in actual operations.

Grafting photochromic spiropyran polymer brushes on natural rubber surface via surface-initiated ring-opening metathesis polymerization

The modification of stereoregulated functionalized polymers on the surface of natural rubber (NR) is a challenging task. This work provided a practicable grafting method to design photochromic polymer brushes on the NR surfaces using surface-initiated ring-opening metathesis polymerization (SI-ROMP). The designed photochromic polymer brushes were based on norbornenes with spiropyrin (SP) pendents, and grew from the surface of NR films in the presence of Grubbs 2nd catalyst. The results showed that the grafting rate of polymer brushes with photoisomerization structure reached up to 44.91 %. The modified natural rubber (NR-SP) films exhibited rapid coloring/decolorization property under UV irradiation and visible light. This photochromic property initiated by the light-induced isomerisation of the spiropyran structure and the increased surface energy under light stimuli. NR-SP films exhibited stable photochromic characteristics and outstanding anti-fatigue properties after exposing to over six cycles of consecutive UV/Vis irradiation. A simple and practical strategy for the preparation of highly sensitive photochromic natural rubber materials is proposed and provides a potential application in the fields of information storage and anti-counterfeiting.

Development of a Multi-Material 3D Printer for Functional Anatomic Models.

Anatomic models are important in medical education and pre-operative planning as they help students or doctors prepare for real scenarios in a risk-free way. Several experimental anatomic models were made with additive manufacturing techniques to improve geometric, radiological, or mechanical realism. However, reproducing the mechanical behavior of soft tissues remains a challenge. To solve this problem, multi-material structuring of soft and hard materials was proposed in this study, and a three-dimensional (3D) printer was built to make such structuring possible. The printer relies on extrusion to deposit certain thermoplastic and silicone rubber materials. Various objects were successfully printed for testing the feasibility of geometric features such as thin walls, infill structuring, overhangs, and multi-material interfaces. Finally, a small medical image-based ribcage model was printed as a proof of concept for anatomic model printing. The features enabled by this printer offer a promising outlook on mimicking the mechanical properties of various soft tissues.

Commodity Rubber Material with Reversible Cross-linking Ability: Application of Boroxine Cross-links to Ethylene-Propylene Rubber

Commodity Rubber Material with Reversible Cross-linking Ability: Application of Boroxine Cross-links to Ethylene-Propylene Rubber

A numerical study of the influence of the choice of rubber material behavior on the static response of tires

A numerical study of the influence of the choice of rubber material behavior on the static response of tires

Simulation of flow characteristics in open channels with inflatable dam

Abstract Inflatable dams are structure cylindrical inflatable and deflated bile structures made of rubberized material placed on top of a rigid base and inflatable by air, water, or a combination of both. The present paper aims to measure the water surface elevation, and depth of flow in Shatt Al Ibrahim and comparison with design depth and study the flow state according to design discharge and also according to scarce discharge. The study effect of the height of the dam filled with water on upstream and downstream water depth and analyzed numerically by using HEC-RAS program one–one-dimensional flow in two states, steady flow and unsteady flow under different variables such as changing of discharge. Good results were obtained in two flow states. The results show that the proper solution for maintaining the required water levels is to construct inflatable dams, due to lower construction and maintenance costs, easy and simple of operation, simple and easy to inflate and deflate quickly to prevent upstream flooding. The results of the current study indicated an increase in the water surface height (WS) and water depth (Wd) across the channel after the implementation of inflatable dams compared to natural conditions. Specifically, the data indicate a significant increase in (WS) and (Wd) at “station 52”, where (WS) increased by 0.45 m with a 0.5 m dam and 1.43 m with a 1.5 m dam compared to the basic scenario. This confirms the adaptability of inflatable dams in adapting water levels to real-time requirements, underscoring their potential as a cost-effective solution to mitigate upstream floods and improve water resource management practices.