Showing papers on "Natural rubber published in 2017"
TL;DR: Using a proper combination of AEO and K-MEPTS is a user-friendly approach for preparing silica/NR composites with excellent performance.
Abstract: The study of preparing silica/rubber composites used in tires with low rolling resistance in an energy-saving method is fast-growing. In this study, a novel strategy is proposed, in which silica was modified by combing alcohol polyoxyethylene ether (AEO) and 3-mercaptopropyltriethoxysilane (K-MEPTS) for preparing silica/natural rubber (NR) master batches. A thermal gravimetric analyzer and Raman spectroscopy results indicated that both AEO and K-MEPTS could be grafted on to the silica surface, and AEO has a chance to shield the mercaptopropyl group on K-MEPTS. Silica modified by AEO and K-MEPTS together was completely co-coagulated with the rubber in preparing silica/NR composites using the latex compounding method with the help of the interaction between AEO and K-MEPTS. The performance of composites prepared by silica/NR master batches was investigated by a rubber process analyzer (RPA), transmission electron microscopy (TEM) and a tensile tester. These results demonstrate that AEO forms a physical interface between silica and rubber, resulting in good silica dispersion in the matrix. K-MEPTS forms a chemical interface between silica and rubber, enhancing the reinforcing effect of silica and reducing the mutual friction between silica particles. In summary, using a proper combination of AEO and K-MEPTS is a user-friendly approach for preparing silica/NR composites with excellent performance.
394 citations
TL;DR: In this paper, the performance of concrete mixtures incorporating 5%, 7.5% and 10% of discarded tyre rubber as aggregate and cement replacements was evaluated. But the results were limited to two sets of concrete specimens.
244 citations
TL;DR: In this article, two surface treatment methods (NaOH, and Silane Coupling Agent) and three coating techniques (coated with normal cement, blended cement with silica fume, and blended cement plus sodium silicate) were used to improve rubber-cement bonding.
206 citations
TL;DR: It appeared that epoxy composites filled with DGTR have better mechanical properties than those filled with untreated GTR, which agrees with scanning electron microscopy observations which highlighted a better interface coherence between DGTR and epoxy.
175 citations
TL;DR: In this paper, the effects of roller compacted concrete (RCC) characteristics on their fracture behavior in both pure mode I and II are experimentally investigated, and the fracture toughness results revealed concrete mix specifications had a noticeable impact on the cracking initiation of RCC and the effect of substituting of waste materials with natural aggregates was found to be negative, although their behavior was still comparable to those obtained for control mixes.
144 citations
TL;DR: A review of thermoplastic vulcanizates (TPVs) can be found in this paper, where the authors focus on recent progresses in TPVs, and more specifically on the mechanisms of formation of the microstructure of TPVs; relationships between the micro-structure and properties; and future challenges on TPVs.
141 citations
TL;DR: In this article, the influence of inclusion of waste rubber tire fibres on some of the geotechnical properties of uncemented/cemented clay was investigated and the results revealed that the incorporation of rubber fibre reduces the unconfined compressive strength and split tensile strength of cement-stabilized clay but prosperously improves the rate of loss of post-peak strength and change the brittle failure behavior of cemented clay to ductile.
133 citations
TL;DR: In this article, the authors investigated the durability of rubberized concrete and concrete samples with NaOH-solution treated rubber particles and found that the added rubber particles improved the freeze-thaw resistance of concrete.
122 citations
TL;DR: The use of crumb rubber in concrete has been practiced for some years as discussed by the authors and it is an effective environmental approach to use to reduce the amount of scrap tyres in landfills around the world.
Abstract: The use of crumb rubber in concrete has been practiced for some years. It is an effective environmental approach to use to reduce the amount of scrap tyres in landfills around the world. However, there are concerns about the mechanical properties of crumb rubber concrete (CRC) and its associated applications. The main purpose of this study is to provide a closer look at different mechanical properties of fibre reinforced polymer (FRP) confined and unconfined CRC with high rubber content. In this study, six concrete mixtures having 0%, 10%, 20%, 30%, 40%, and 50% rubber content replacement of sand volume were produced. Different mechanical properties including compressive strength, tensile strength, modulus of elasticity, unit weight, impact resistance, water absorption, temperature effect, stress-strain behaviour, and FRP-confinement effect were measured. The results indicated that the use of FRP to confine rubberized concrete effectively negates the decrease in strength, and retains the advantages of increased ductility that arise from rubberized concrete. In addition, increasing concrete rubber content from zero to 50% increased its impact resistance by approximately 3.5 times. This indicates promising potential for structural applications, particularly in seismic zones.
113 citations
TL;DR: It was found that CNT offered a strong strain dependent character in the regime 100% to 150% elongation, whereas, the carbon black filled natural rubber showed strong strain dependencies at 50% to 100% elongations strain.
Abstract: A detail study concerning the strain (tensile) dependent electrical conductivity of elastomeric composites is reported in this present paper. Multiwall carbon nanotubes (CNT), conducting carbon black (CB), and their combinations were considered as conducting filler in cross-linked natural rubber matrix. The loadings of the fillers were considered from 3 to 11 phr (filler concentration close to their percolation threshold). Without hindering the elastic nature of the composite (reversible stretchability up to several 100%), the change of relative resistance, ΔR/R0 (ΔR is the change in the resistance with respect to strain and R0 is the initial resistance of the sample) of the CB filled composites was found to be as much as ∼1300 at around 120% elongation. This value is much higher than any other reported values obtained from conducting polymeric composites. It was found that CNT offered a strong strain dependent character in the regime 100% to 150% elongation, whereas, the carbon black filled natural rubbe...
111 citations
TL;DR: In this article, an analysis of the mechanical and thermal properties of a sustainable concrete incorporating crumb rubber (CR) and steel or plastic fibres partially coated with rubber (FCR) is presented.
TL;DR: In this paper, a facile synthesis of conducting polymer nanocomposite by incorporating non-covalently functionalized Multi walled Carbon Nanotube (MWCNT) with ionic liquid into SBR matrix and achieve a shielding efficiency of ca.35.
TL;DR: In this paper, the rubber seed powder was extracted with hexane at room temperature to give rubber seed oil with the yield of 24% and the composition and key properties of the extracted oil were analyzed including fatty acid compositions, density, kinematic viscosity, flash point, water content and acid value.
TL;DR: In this article, the low temperature properties of crumb rubber modified binder (CRMB) are governed by the factors such as asphalt properties, crumbs rubber properties, mixing temperature, mixing time, mixing type and admixture.
TL;DR: In this article, the authors measured compressive strength, water absorption, ultrasonic pulse velocity in concrete modified with crumb rubber, and calculated structural performance indicators of concrete specimens, showing that higher content of rubber in the mix reduces the relative pore and capillary wall thickness and the spare pore space.
TL;DR: The results indicate that a synergistic effect between molecular interdiffusion and dynamic hydrogen bond supramolecular networks leads to the improved self-healing behavior.
Abstract: Cellulose nanocrystals represent a promising and environmentally friendly reinforcing nanofiller for polymers, especially for rubbers and elastomers. Here, a simple approach via latex mixing is used to fabricate biobased, healable rubber with high strength based on epoxidized natural rubber (ENR). Tunicate cellulose nanocrystals (t-CNs) isolated from marine biomass with a high aspect ratio are used to improve both mechanical properties and self-healing behavior of the material. By introducing dynamic hydrogen bond supramolecular networks between oxygenous groups of ENR and hydroxyl groups on the t-CN surface, together with chain interdiffusion in permanently but slightly cross-linked rubber, self-healing and mechanical properties are facilitated significantly in the resulting materials. Macroscopic tensile healing behavior and microscopic morphology analyses are carried out to evaluate the performance of the materials. Both t-CN content and healing time have significant influence on healing behavior. The results indicate that a synergistic effect between molecular interdiffusion and dynamic hydrogen bond supramolecular networks leads to the improved self-healing behavior.
TL;DR: In this paper, a bi-sheath buckled structure is designed containing buckled carbon nanotube sheets and buckled rubber on rubber fiber, which can be reversibly stretched to 600%, undergoing a linear resistance increase as large as 102% for 0-200% strain and 160% for 200-600% strain.
Abstract: Current research about resistive sensors is rarely focusing on improving the strain range and linearity of resistance–strain dependence. In this paper, a bi-sheath buckled structure is designed containing buckled carbon nanotube sheets and buckled rubber on rubber fiber. Strain decrease results in increasing buckle contact by the rubber interlayer and a large decrease in resistance. The resulting strain sensor can be reversibly stretched to 600%, undergoing a linear resistance increase as large as 102% for 0–200% strain and 160% for 200–600% strain. This strain sensor shows high linearity, fast response time, high resolution, excellent stability, and almost no hysteresis.
TL;DR: In this article, the results show that GE/NR nanocomposites feature the improved mechanical properties, dynamic properties and low internal heat rise, and the results also show that they are more robust to high temperature and high humidity.
Abstract: Owing to its striking electrical, mechanical, thermal and gas barrier properties, graphene has been considered as a most promising reinforcing filler for development of rubber nanocomposites. In the present work, we fabricate graphene/natural rubber (GE/NR) nanocomposites by direct mechanical mixing. The pristine graphite was first oxidized according to Hummers method to prepare graphene oxide (GO), and then graphene was obtained by chemical reduction of GO. The mechanical properties, dynamic properties and internal heat rise of GE/NR nanocomposites have been investigated in detail. The results show that GE/NR nanocomposites feature the improved mechanical properties, dynamic properties and low internal heat rise.
TL;DR: In this article, an overview of methods for improving the storage stability at high temperature of rubber modified bitumen is presented, where various types of modifiers are used to form the bonds between the components of these binders.
TL;DR: In this article, a detailed account of a set of material tests on rubberised concrete cylindrical samples, in which fine and coarse mineral aggregates are replaced in equal volumes by rubber particles with various sizes, is presented.
TL;DR: In this article, the authors characterize organic peroxides as curing agents and their decomposition mechanisms and characteristics and bring a detailed view to understand mechanisms between peroxide and different types of rubber matrices.
Abstract: Vulcanization or curing is one of the most important processes in rubber technologies. During this process, plastic rubber compounds by parallel and subsequent physical and mainly chemical reactions change into highly elastic products—vulcanizates. The fundamental goal of curing is forming chemical cross-links between rubber macromolecules, which leads to the formation of a three-dimensional network or rubber matrix. A number of curing systems have been introduced in cross-linking of elastomers; each system has its own characteristics and composition; therefore, vulcanizates with different properties also can be prepared. We characterize organic peroxides as curing agents and their decomposition mechanisms and characteristics and bring a detailed view to understanding mechanisms between peroxides and different types of rubber matrices. Then, we focus on the classification and characterization of co-agents used in peroxide cross-linking and explain the mutual interactions and reaction mechanisms b...
TL;DR: In this article, a solution-drop method was used to prepare a bifunctional cathode layer on the cathode current collector of a Li-S battery, which can capture a lithium polysulfide soluble in a liquid organic electrolyte by forming a C-Li-S bond during discharge.
Abstract: Vulcanized rubber products contain polymer backbones crosslinked with sulfur to improve mechanical strength. Burning of waste rubber products emits toxic gases, and recycling of rubber by breaking the C–S bond with costly reagents and heat is also haunted by environmental concerns. The crosslinked polymers can be extracted chemically at room temperature and, by a simple solution-drop method, used to prepare a bifunctional cathode layer on the cathode current collector of a Li–S battery. The C–S bond of the crosslinking sulfur can be broken reversibly in a discharge/recharge cycle to provide a sulfur source, and the broken carbon bond can capture a lithium polysulfide soluble in a liquid organic electrolyte by forming a C–Li–S bond during discharge. During charge, the Li is extracted and the C–S bond is reformed. However, added sulfur powder is also needed in the cathode of a Li–S battery. The data also provide a low-cost way to recycle waste rubber electrochemically.
TL;DR: The present study provides a simple method to fabricate a new self-healing NR with tailorable mechanical properties that may have more potential applications.
Abstract: In most cases, the strength of self-healing supramolecular rubber based on noncovalent bonds is in the order of KPa, which is a challenge for their further applications. Incorporation of conventional fillers can effectively enhance the strength of rubbers, but usually accompanied by a sacrifice of self-healing capability due to that the filler system is independent of the reversible supramolecular network. In the present work, in situ reaction of methacrylic acid (MAA) and excess zinc oxide (ZnO) was realized in natural rubber (NR). Ionic cross-links in NR matrix were obtained by limiting the covalent cross-linking of NR molecules and allowing the in situ polymerization of MAA/ZnO. Because of the natural affinity between Zn2+ ion-rich domains and ZnO, the residual nano ZnO participated in formation of a reversible ionic supramolecular hybrid network, thus having little obstructions on the reconstruction of ionic cross-links. Meanwhile, the well dispersed residual ZnO could tailor the mechanical properties...
TL;DR: In this article, a high reactive sulfocompound, sulfur monochloride, was chemically supported onto the surface of silica by the reaction between chloric atom and silanol hydroxyl to obtain a novel vulcanizing agent, silica-s-S2Cl2.
TL;DR: In this paper, a novel hybrid of polymer functionalized-carbon nanotube and reduced graphene oxide (PCNT@RGO) was prepared by reversible addition-fragmentation chain transfer polymerization, esterification reaction and reduction process.
TL;DR: Extracting the free chains (oligomers) from the silicone elastomers is shown to make the work of adhesion independent of the number of contacts, and carbon black filled hydrogenated nitrile butadiene rubber compounds reveal that strain softening at the crack tip may play an important role in determining the workof adhesion.
Abstract: Adhesion between silica glass or acrylic balls and silicone elastomers and various industrial rubbers is investigated. The work of adhesion during pull-off is found to strongly vary depending on the system, which we attribute to the two opposite effects: (1) viscoelastic energy dissipation close to an opening crack tip and (2) surface roughness. Introducing surface roughness on the glass ball is found to increase the work of adhesion for soft elastomers, while for the stiffer elastomers it results in a strong reduction in the work of adhesion. For the soft silicone elastomers a strong increase in the work of adhesion with increasing pull-off velocity is observed, which may result from the non-adiabatic processes associated with molecular chain pull-out. In general, the work of adhesion is decreased after repeated contacts due to the transfer of molecules from the elastomers to the glass ball. Thus, extracting the free chains (oligomers) from the silicone elastomers is shown to make the work of adhesion independent of the number of contacts. The viscoelastic properties (linear and nonlinear) of all of the rubber compounds are measured, and the velocity dependent crack opening propagation energy at the interface is calculated. Silicone elastomers show a good agreement between the measured work of adhesion and the predicted results, but carbon black filled hydrogenated nitrile butadiene rubber compounds reveal that strain softening at the crack tip may play an important role in determining the work of adhesion. Additionally, adhesion measurement under submerged conditions in distilled water and water + soap solutions are also performed: a strong reduction in the work of adhesion is measured for the silicone elastomers submerged in water, and a complete elimination of adhesion is found for the water + soap solution attributed to an osmotic repulsion between the negatively charged surface of the glass and the elastomer.
TL;DR: In this paper, a variety of technological tools were employed to characterise the pyrolysis of natural and synthetic rubbers, which included three tyres (natural rubber tyre, pneumatic tyre and synthetic rubber mat) and one natural rubber mat.
TL;DR: In this paper, the effect of partial replacement of fine aggregate by waste rubber fiber on the properties of concrete subjected to elevated temperature has been evaluated in a systematic experimental investigation, and the results of experimental studies available for rubberized concrete provide a strong recommendation for the use of this waste where strength is not a major concern.
TL;DR: In this article, a thermogravimetric analyzer combined with a mass spectrometer (MS) was used to investigate waste tyre pyrolysis characteristic, and the functional groups at the surface of residue char were also characterized by a Fourier transform infrared (FTIR) spectrometers.