Reduction In Rolling Resistance Research Articles

Tire tread rubber compound with high wet skid resistance and low rolling resistance

AbstractThe preparation of four types of epoxidized iron‐based comb butadiene‐isoprene rubber (EBIR) with different epoxidation degrees (4.7%, 6.4%, 10.2%, and 12.3%) was investigated for the first time in this study. The modification involved the use of hydrogen peroxide and formic acid as raw materials for the epoxidation process. Following this, silica/EBIR composites were prepared by mixing EBIR with silica nanoparticles, without the use of a silane coupling agent (SCA). The objective was to investigate the influence of the epoxidation degree on the structure and properties of the resulting silica/EBIR nanocomposites. The results indicated that the introduction of epoxy groups had a positive effect on the interfacial interaction between the rubber and filler, leading to improved dispersion of the silica nanoparticles in the rubber matrix. Consequently, the tensile properties, wet skid resistance, and abrasion resistance of the silica/EBIR composites were found to be superior to those of the un‐epoxidized silica/BIR composites. Furthermore, comparing the silica/EBIR‐12.3 nanocomposites with silica/BIR‐Si69 nanocomposites, it was revealed that silica/EBIR‐12.3 showed a 69.4% enhancement in wet skid resistance and an 8.0% reduction in rolling resistance. These findings demonstrate the potential of silica/EBIR composites for high‐performance tire tread rubber applications, offering environmental benefits and improved properties.

Exploring the reinforcement and conductivity mechanism of K2FeO4‐modified multiwalled carbon nanotubes in carbon black/natural rubber composites

AbstractThis study employs potassium ferrate (K2FeO4) for the oxidation treatment of multi‐walled carbon nanotubes (MWNTs) under neutral and acidic conditions. A wet flash evaporation process is utilized to prepare natural rubber/MWNTs/carbon black composites, enhancing the performance of rubber composites. The increased oxidation level of MWNTs enhances their hydrophilicity, increases the quantity of oxygen‐containing hydroxyl groups on the surface, promotes dispersion within the natural rubber matrix, and ultimately improves the performance of the rubber products. The effective dispersion of MWNTs reduces electron transport resistance, forming a favorable electron transport channel in natural rubber. Experimental results indicate that K2FeO4 achieves the highest oxidation degree and optimal performance in an acidic environment. Compared to untreated MWNTs rubber composites, the oxidized MWNTs rubber composites exhibit a 34.9% reduction in the Payne effect, a 15.7% decrease in wear, a 12.7% reduction in rolling resistance, and a two‐order‐of‐magnitude increase in conductivity. This study provides a novel approach for preparing water‐dispersible MWNTs and high‐performance rubber composites, holding potential applications in premium rubber products and conductive rubber fields.Highlights The wet flash refining process improved the dispersion of MWNTs. K2FeO4 oxidation of MWNTs was enhanced under acidic conditions. Oxidized MWNTs combined with CB to form a CB‐MWNTs‐CB filler network. Oxidized MWNTs and CB increased the “ball‐chain” arrangement in NR.

Advancing mechanical performance in sustainable engineering: Synergistic effects of graphene oxide/nano‐silica hybrid nanofiller via latex coagulation in natural rubber composites

AbstractThis research investigates the utilization of a hybrid nanofiller comprising graphene oxide (GO) and amine‐modified nano silica in natural rubber matrix via the latex stage coagulation method. The resulting novel composite materials were characterized comprehensively for their static and dynamic mechanical properties. The hybrid nanofiller exhibited excellent dispersion within the rubber latex, facilitating the formation of a well‐interconnected network structure. The formed network resulted in remarkable improvements in tensile strength, elongation at break, and modulus of the composites. Dynamic mechanical analysis revealed that the hybrid filler (GO/nano‐silica hybrid (GO/NS)) could effectively reinforce the rubber matrix by constraining the mobility of rubber chains, leading to increased stiffness and mechanical strength. In fact, the confinement effect of the nanofillers has been carefully evaluated from dynamic mechanical spectroscopy. The increased glass transition temperature of the rubber nanocomposites specifies the restricted segmental mobility of the rubber chains. Moreover, the hybrid composites displayed significantly low rolling resistance, particularly GO/NS 2 (31% reduction), indicating their potential application as tire treads for fuel‐efficient and green tire manufacturing. The mechanical and rolling resistance properties achieved in these composites can be attributed to the efficient dispersion of the GO/nano‐silica hybrid(GO/NS) nanofiller and the resulting network formation within the rubber matrix. Findings emphasized the composites' viability as sustainable and eco‐friendly tire materials, potential for enhanced fuel efficiency, and reduced environmental footprint in tire manufacturing technology.Highlights The hybrid nanofiller (GO/nano silica hybrid) exhibited excellent dispersion within the rubber latex, leading to the formation of a well‐interconnected network structure. The resulting network structure significantly improved the tensile strength, elongation at break, and modulus of the composite materials. Dynamic mechanical analysis demonstrated that the hybrid filler effectively reinforced the rubber matrix, increasing stiffness and mechanical strength by constraining the mobility of rubber chains. Our hybrid composites displayed a remarkable reduction in rolling resistance, particularly GO/NS2, with a 31% reduction, indicating their potential application as tire treads for fuel‐efficient and green tire manufacturing. The study emphasized the composites viability as sustainable and eco‐friendly tire materials, offering potential benefits for enhanced fuel efficiency and reduced environmental footprint in tire manufacturing technology.

Structure and performance of silica/functionalized solution-polymerized styrene butadiene rubber/epoxidized butadiene rubber nanocomposites

Functionalized solution-polymerized styrene butadiene rubber (FSSBR) is extensively used in “green tires” tread, so it is very important to improve the phase distribution of silica in FSSBR blends. In this work, the butadiene rubber (BR) is epoxidized (EBR) and blended with FSSBR. The effect of epoxidation degree on the structure and performance of the silica in combination with bis-(γ-triethoxysilylpropyl) disulfide (TESPD) filled FSSBR/EBR nanocomposites (S/FSSBR/EBR) is investigated. S/FSSBR/EBR3 nanocomposite with epoxidation degree of 3% achieves the best dispersion and phase distribution of silica by ring-opening reaction between epoxy group of EBR and silanol group of silica. Compared with silica in combination with TESPD filled FSSBR/BR nanocomposite (S/FSSBR/BR), S/FSSBR/EBR3 has better abrasion resistance, 13% improvement in wet-skid resistance and 15% reduction in rolling resistance, which provides an excellent solution for the preparation of high-performance “green tires".

Silane coupling agent 3‐aminopropyltriethoxysilane modified silica/epoxidized solution‐polymerized styrene butadiene rubber nanocomposites

AbstractIn this paper, epoxidized solution‐polymerized styrene butadiene rubber (ESSBR) as the matrix and silica as filler, a small quantity of 3‐aminopropyltriethoxysilane (APTES) is used to adjust the cross‐linking network of ESSBR/silica. The effect of two APTES addition methods (ESSBR/APTES/silica and ESSBR/silica/APTES) on the nanocomposite properties is investigated. The epoxy groups of ESSBR and the ethoxy groups of APTES can react with the hydroxyl groups on silica to improve dispersion. At the same time, the amino groups at another end of APTES can react with the epoxy groups of ESSBR to increase the cross‐linking density. Compared with bis(3‐triethoxysilylpropyl) disulfide (TESPD) modified SSBR/silica (SSBR/TESPD/silica), ESSBR/APTES/silica shows 133% improvement in wet‐skid resistance, 14% reduction in rolling resistance with less silane coupling agent and volatile organic compounds emissions. ESSBR/APTES/silica has excellent overall performance and offers a good prospect for the preparation of green tire tread.Highlights APTES modified silica/ESSBR nanocomposites are prepared. Epoxy groups and APTES react with silica to improve dispersion. APTES can increase the cross‐linking density. The nanocomposite has excellent comprehensive performance as green tire tread. The nanocomposite has less silane coupling agent and VOCs emission.

Synthesis of high-reinforcing-silica@nanodiamond nanohybrids as efficient particles for enhancement of mechanical, thermal, and rolling resistance of styrene-butadiene rubber

Present work illustrated that the performance of ultrafine silica (Si) particles was improved considerably by rational hybridization with nanodiamond (ND). For this, [email protected] hybrid particles synthesized by chemical hybridization were incorporated into styrene-butadiene rubber (SBR) up to 10 phr. Scanning electron microscopy revealed coarse flower-like clusters for [email protected] nanohybrids, while Si exhibited rigid agglomerates in SBR. Comparing with physical hybrid (Si&ND) and single Si particles, it was revealed that chemical hybrids synergistically improved tensile properties, like 100% and 135% improvements in tensile strength and elongation at break, respectively. Dynamic mechanical analysis of SBR/[email protected] revealed an increment of the wet skid (22%) compared with SBR and further reduction of rolling resistance, to ∼35%, with respect to SBR/Si due to better dispersion and improved polymer-filler interactions. Thermal conductivity of SBR increased considerably, i.e., ∼54%, by the inclusion of [email protected]%ND, which was explained based on the promotion of phonon pathways.

Vulcanizate Structures of SBR Compounds with Silica and Carbon Black Binary Filler Systems at Different Curing Temperatures.

The tire industry has shown an increasing demand for the reduction in rolling resistance. Efforts have been made to improve the viscoelastic properties of tire compounds and reduce the weight of tires through optimization of the vulcanizate structure, which has become extremely complex. In this study, vulcanizates using carbon black and silica as binary fillers were prepared at various curing temperatures. Vulcanizate structures with respect to curing temperature were classified according to the chemical crosslink density by sulfur, carbon black bound rubber (i.e., physical crosslink due to carbon black), and silica-silane–rubber network. All properties exhibited a decreasing trend under the application of high curing temperatures, and the decrease in the crosslink density per unit content of filler with an increase in curing temperature was shown to be greater in carbon black than in silica. Mechanical and viscoelastic properties were also measured to evaluate the impact that the compound variates have on tire tread performance. These results serve as a guideline for determining the content and filler type and for setting the cure condition during the design of actual compound formulations to increase the crosslink density of rubber while retaining the necessary mechanical and viscoelastic properties for practical application.

The Effects of Various Ratios of Hybrid Filler to Rubber Vulcanisates Properties Based on Passenger Car Tyre Tread Compounds

Solution styrene-butadiene rubber (SSBR) reinforced by hybrid fillers of carbon black (CB) and silica (PSi) was prepared with various CB/PSi ratios. Rheological and mechanical properties of rubber compounds and vulcanisates were investigated. Results of compounds demonstrate that, with increasing CB fraction, increases in the magnitude of the Payne effect and Mooney viscosity were found. On the contrary, with increased loading of PSi, increases in optimum cure time (tc90) and cure torque difference were evidenced. The results suggest superiority in filler dispersion level and cure efficiency in the systems filled with high PSi fraction due to the presence of Bis [3-(triethoxysilyl) propyl] tetrasulphide (TESPT or Si-69) as a silane coupling agent. As for vulcanisate properties, the systems with increased PSi fraction exhibit enhancement in mechanical strength and elastic contribution, which are in good agreement with rubber compound properties. Also, the decrease in loss factor at 60 °C was observed with increasing PSi fraction, suggesting the desirable reduction in rolling resistance of tyre tread.

Multi-chamber tyre designing for fuel economy

Rolling resistance plays a major role in tyre development due to its significant influence on energy consumption and environmental impact. Numerous efforts to minimise the tyre’s rolling resistance have met with no or minor success because of the tyre’s complexity and the involved compromises. This paper explores a novel design solution of the multi-chamber tyre, as a potential alternative, for low rolling resistance while meeting other driving requirements – a multi-purpose generalised solution (design-for-all). A novel multi-chamber design (base design) with a validated finite element model was used to create the different novel designs. Statistical analysis based on the design of experiment was conducted to identify the best cavity volumes and inflation settings. The ‘design-for-all’ solution offered a 28% reduction in rolling resistance, an enhanced cornering performance, a matching grip and a satisfactory cushioning.

Tire tread rubber compounds with ternary system filler based on carbon black, silica, and metakaolin: Contribution of silica/metakaolin content on the final properties

Carbon black and high performance silica have been widely employed as binary system filler in tire tread formulations. This study evaluated the total and partial substitution of silica by metakaolin (MK) on the properties of tread rubber composites. Dynamic mechanical thermal analysis and abrasion tests were conducted as typical assessments of tire tread performance: rolling resistance (fuel consumption), wet traction (safety), and abrasion (durability). Further the energy spent by the equipment during the processing of formulations was also analyzed, as well as rheological and mechanical properties. A significant reduction of rolling resistance was obtained with 75% and 100% of silica substitution by MK, which could lead to lower heat buildup in tire tread applications, without showing negative effects on wet traction, although abrasion showed undesired results. The substitution of silica by MK also lowered energy demanded for processing. No major changes were observed in vulcanization parameters and mechanical properties, which is interesting considering the fact that MK is nonreinforce filler.

Concurrently improved dispersion and interfacial interaction in rubber/nanosilica composites via efficient hydrosilane functionalization

Surface modification of fillers has a profound influence on the dispersion of filler and interfacial adhesion, and thus the final performance of polymer-based composites. In this contribution, the modification of silica by polymethylhydrosiloxane (PMHS) is conducted via an efficient and fast tris(pentafluorophenyl)borane-catalyzed functionalization, which can be completed within a few minutes at room temperature. A highly hydrophobic surface and an uncompromised reactivity are concurrently observed in the modified silica. By comparison between the composites filled with pristine and modified silica, it is revealed that such PMHS modification can not only improve the dispersibility of silica by lowering the surface energy, but also enhance the interfacial interaction in virtue of the reactivity of the residual SiH bonds. With a PMHS grafting content as low as 1.5 wt%, the modified composite exhibits tremendous improvements in mechanical properties (116% increase in modulus) and dynamic performances (116% increase in wet traction and 26% reduction in rolling resistance). Considering the superior overall performance of the modified composites, together with the simplicity and rapidity of the modification process, we envision that the hydrosilane-modified silica has great potential in the fabrication of high-performance polymer composites such as energy-saving tire treads.

Modeling fuel efficiency for heavy duty vehicles (HDVs) in India

Transport sector accounts for almost 70% consumption of diesel in India. With increased dependency on road transportation for freight transport, there is a need to develop fuel-efficiency standards for the heavy duty vehicles (HDVs). This study models the fuel efficiency of the existing fleet of HDVs and compares it with the world’s best practices. The model uses the technical details of the existing HDV fleet and the prescribed driving cycles to assess fuel efficiency. The results of the model are validated with the actual test results of fuel efficiency observed for HDVs in India. The model presents a fuel economy of 2.65 km/l for truck and bus model of given specification. The validated model is then used for evaluating the potential of different strategies to improve fuel efficiency. The models estimate a potential of about 36% improvement in the fuel efficiency in the HDVs in India through improvements in thermal efficiency, reduction in rolling resistance, and reduction in vehicle weight. The study provides a direction for the possible fuel efficiency improvements in HDV sector in India.

Evaluation method of pavement surface characteristics for rolling resistance

Pavement technology intended to reduce tyre-pavement rolling resistance is a new technology for establishing the future low-carbon society. Reduction of rolling resistance leads to reduce vehicle CO2 emission and to improve fuel efficiency. However, the relation between rolling resistance and pavement surface characteristics is complex and there are some issues to be solved including clarifying the evaluation methods. The evaluation method for rolling resistance generally involves measuring the rolling resistance coefficient directly; however this direct measurement requires special measurement devices. Indirect evaluation methods will make measurements easier and help put low-rolling resistance pavement technologies to practical use. This paper reports the results on determining the contact pressure distribution between tyre and pavement surfaces using a pressure measurement film to evaluate the rolling resistance indirectly. The results of analyses the relations between the rolling resistance and pavement surface characteristics, it were revealed that the contour map of contact pressure distribution were fully different depending on the pavement surface texture and it would be useful to evaluate the negative texture that lead to the low-rolling resistance pavement surface.

Tyre rolling resistance and its influence on fuel consumption

Rolling resistance of tyres is one of the major resistive forces acting on any wheeled vehicle. Unfortunately, it is also one of the forces very difficult to measure. It is estimated that in certain traffic conditions (like for example constant speed driving with slow or moderate speed) so called Rolling Resistance Impact Factor may be as high as 0.3. This means that reduction of rolling resistance by 50% would lead to 15% of energy savings. The paper presents road measuring method of tyre rolling resistance and unique equipment used by the Technical University of Gdańsk designed to perform measurements of passenger car tyres. It also discusses road pavement, tyre and environmental conditions influence on rolling resistance. Also selected data describing current situation related to rolling resistance on different road pavements and rolling resistance of modern passenger car tyres including tyres specially designed for electric and hybrid vehicles are presented.

Targeted Efficiency Optimisation for Gasoline Engines

The European Union’s mandatory CO2 standards for new passenger cars in 2009 set a 2015 target of 130 g/km for the fleet average of all manufacturers combined, which was met in 2013, with average EU fleet emissions amounting to 129 g/km. Individual manufacturers are allowed a higher CO2 emission value, depending on the average vehicle weight of their fleet. The heavier the average weight of the cars sold by a manufacturer, the higher the CO2 level allowed. Figure 1 shows that in order to meet the future EU emissions regulations, significant increases in gasoline engine efficiency will have to be realised. Open image in new window FIGURE 1 European CO2 targets and the derived average fuel consumptions resulting from efficiency improvements for the C- and D- vehicle segments for European passenger car markets for the intervals 2015-2021 and 2021-2025 (© FEV) Based on two representative vehicles from the C- and D-segment, which meet the present day CO2 targets, it can be demonstrated that there is a need to improve efficiency for the intervals 2015 to 2021 and 2021 to 2025. The CO2 targets of the two vehicles have been converted to specific fuel consumption targets for each of comparison. The common reduction measures — reduction in vehicle mass, reduction of rolling resistance — and electrification of the powertrain (Micro-HEV, Mild-HEV, HEV) are already considered. — In a C-Segment vehicle, the engine is allowed a maximum average fuel consumption of 256 g/kWh in 2021 and for 2025 it should be 223 g/kWh (Micro-HEV). — In a D-Segment vehicle, the engine is allowed a maximum average fuel consumption of 238 g/kWh in 2021 and for 2025 it should be 213 g/kWh (Micro-HEV). The specification of such an average fuel consumption map is readily comparable across different driving cycles and therefore provides a simple way of evaluating the various technologies in a wide scope. In contradiction, the use of micro-hybridisation to advance electrification of the gasoline engine, allows a slight increase in the maximum allowable average Brake Specific Fuel Consumption (BSFC); but the Micro-HEV must be increasingly used in the new fleet of vehicles [3]. In the analysis presented here, a three-cylinder and a four-cylinder gasoline engine are considered: — 1.0-l three-cylinder turbocharged gasoline engine with direct injection, capable of 200 Nm and 90 kW — 1.6-l four-cylinder turbocharged gasoline engine with direct injection, capable of 250 Nm and 115 kW. Both engines are turbocharged and equipped with direct fuel injection and have intake and exhaust cam phasers. Figure 2 shows the full engine operating range of the 1.0-l- and 1.6-l engines with focus on fuel consumption in the New European Drive Cycle (NEDC) and Worldwide Harmonized Light-Duty Vehicles Test Procedure (WLTP) driving cycles for the C- and D-segment vehicles. Open image in new window FIGURE 2 Engine operating range of the 1.0-l and 1.6-l engines with focus on fuel consumption (marked with red/gray outline) on the NEDC and WLTP driving cycles for the C- and D-segment vehicles (© FEV) Comparing the individual engine maps in Figure 2, it is clear to see that the average fuel consumption would be highly influenced by the different driving cycles and target vehicles. Especially when considering the high load WLTP-H (WLTP with highest vehicle mass) cycle, extended areas of the engine map will also need to be optimised. Technologies with efficacy in broad regions of the engine map will definitively have an advantage. To this effect, the next section will analyse the effectiveness of the individual fuel consumption reduction technologies.

A model for investigating the influence of road surface texture and tyre tread pattern on rolling resistance

The reduction of rolling resistance is essential for a more environmentally friendly road transportation sector. Both tyre and road design can be utilised to reduce rolling resistance.In both cases a reliable simulation tool is needed which is able to quantify the influence of design parameters on the rolling resistance of a tyre rolling on a specific road surface. In this work a previously developed tyre/road interaction model is extended to account for different tread patterns and for losses due to small-scale tread deformation. Calculated contact forces and tyre vibrations for tyre/road interaction under steady-state rolling are used to predict rolling losses in the tyre. Rolling resistance is calculated for a series of different tyre/road combinations. Results are compared with rolling resistance measurements. The agreement between simulations and measurements is generally very good. It is found that both the tyre structure and small-scale tread deformations contribute to the rolling losses. The small-scale contribution depends mainly on the road roughness profile. The mean profile depth of the road surface is identified to correlate very well with the rolling resistance. Additional calculations are performed for non-traditional rubberised road surfaces, however, with mixed results. This possibly indicates the existence of additional loss mechanisms for these surfaces.

Tailoring Silica Surface Properties by Plasma Polymerization for Elastomer Applications

The surface properties of reinforcing fillers are a crucial factor for dispersion and filler–polymer interaction in rubber compounds, as they strongly influence the final vulcanized properties of the rubber article. Silica is gaining more and more importance as reinforcing filler for rubbers, as it allows for a reduction of rolling resistance and thus energy losses in tires, compared to the use of carbon black as filler. However, silica and common elastomers differ greatly in polarity and, therefore, are difficult to mix and thus have little interaction. In the present study plasma-coating of silica-filler with acetylene, thiophene and pyrrole is applied, and the surface-treated silicas are blended with S-SBR rubber, in an attempt to enhance the compatibility between the two. The dispersion and reinforcing effects of the modified silicas are investigated and compared with untreated and silanized silica. The relative rankings of the various coatings in reduction of filler–filler interaction, improved dispersion, enhanced polymer–filler interaction, apparent crosslink density and tensile mechanical properties are mutually different. Where the best silica dispersion and largest reduction in filler–filler interaction are obtained with polyacetylene coating and the worst with polythiophene coating, but the tensile properties achieved with the polythiophene coating are far better than all others. Apparently, the sulfur contained in the thiophene-moiety enhances the filler–polymer interaction and contributes to the degree of crosslinking. Unmodified silica performs worst in all aspects, also because its acidic nature harms the preferably alkaline vulcanization process. Silane treatment of silica has a positive effect on reduction of filler–filler interaction and improved dispersion, but has little effect on polymer–filler interaction in the still unvulcanized state. Its tensile properties after vulcanization are comparable with polyacetylene- or polypyrrole-coated silica. This investigation shows that the compatibility and interaction of silica with a polymer can be controlled by tailoring the surface energy of the filler by coating with plasma polymers. An appropriate monomer for the plasma polymerization process allows to improve the cured rubber properties.

低燃費タイヤを指向した末端変性溶液重合ＳＢＲに関する研究

In recent, the reduction of rolling resistance of tires has become more significant in the tire industry, because it has close relation to the fuel consumption efficiency and CO2 emission of motor vehicles. Rolling resistance of tire is closely related to hysteresis loss properties of tire tread compounds. Dispersibility of filler is considered to affect hysteresis loss. Some styrene-butadiene rubbers with functional groups at chain ends have been developed by solution polymerization system (S-SBRs) to achieve good interaction with silica filler. They showed significant reduction in the hysteresis loss of silica reinforced compounds. Especially, the modified S-SBR with both primary amino group and alkoxysilyl group exhibited excellently lower hysteresis loss properties. In order to observe the dispersibility of silica in compounds with this modified S-SBR directly, the measurements of transmission electron microscopy (TEM) and ultra small angle X-ray scattering (USAXS) were carried out. As the results, the excellent dispersion states of silica in the compounds with this modified S-SBR was observed, and we found that smaller size of silica aggregates could reduce the hysteresis loss to much lower level. This result coincided with those obtained by dynamic viscoelstic measurement.

環境・衛生関連 タイヤにおける環境対応型新材料技術

Environment protection is and will be the most important aspect of the tire development. A study of tire's life cycle assessment (LCA) was conducted under Japan Rubber Manufacturers Association, and revealed that the usage stage accounts for more than 85% of total CO2 emission in an entire life cycle of a common tire. From this standpoint, reduction of rolling resistance (RR) is the most important requirement, followed by extension of service life, which contributes to all other stages. Following the development of silica-filled tread compound, further reduction of hysteresis loss had been achieved by development of new materials for silica system, such as dispersion additive and novel modified polymers. In addition, recent implementation of non-linear viscoelastic properties in the Finite Element Analysis has greatly improved the precision of tire RR prediction. This will allow efficient application of low hysteresis materials in tire design.

Tyre Design Technology for Reduction of Rolling Resistance

Tyre Design Technology for Reduction of Rolling Resistance