Mechanical Properties Of Styrene Butadiene Rubber Research Articles

Compressive mechanical properties of styrene-butadiene rubber under medium-low strain rates: Experiments and modeling

Styrene-butadiene rubber (SBR) is widely employed as a cushioning material in engineering applications to resist impact loadings due to its excellent mechanical properties and energy absorption capacity. This paper aims to investigate the compressive mechanical properties and constitutive model of SBR under medium–low strain rates both experimentally and theoretically. Firstly, quasi-static and dynamic compression tests of SBR were carried out under the strain rate up to 220 s−1 using an electronic universal testing machine and a drop-weight machine, respectively. Subsequently, the effect of loading rate on mechanical properties, strain rate sensitivity and energy absorption capacity was examined. The results indicate that SBR exhibits visco-hyperelastic characteristics with reversible compression deformation and strain rate dependency, ie., the yield stress, flow stress and dynamic increase factor (DIF) increase approximately exponentially with increasing logarithmic strain rate. In addition, the SBR exhibits excellent energy absorption capacity during compression, especially under higher strain rates and larger strain levels. Finally, a visco-hyperelastic constitutive model was proposed by replacing the nonlinear spring with a hyperelastic element in Zhu-Wang-Tang (ZWT) viscoelastic constitutive model to describe the nonlinear mechanical behaviors in SBR, and an acceptable agreement between experimental results and model predictions were observed. The findings of this research can provide a valuable guide for designing and optimizing the impact resistance of SBR structures.

The effect of POSS nanoparticles on crosslinking of styrene-butadiene rubber nanocomposites.

The effect of octaisobutyl-polyhedral oligomeric silsesquioxane (OIB-POSS) as a nanosized reinforcement on the cure kinetics, crosslinking density, and mechanical properties of styrene-butadiene rubber (SBR) nanocomposites was examined in this study. For this purpose, SBR compounds with various OIB-POSS nanoparticle loadings at 1, 3, and 5 phr were prepared and their results were compared with a reference compound without OIB-POSS. When 1 phr of OIB-POSS was added to the rubber matrix, the elongation at break values and tensile strength of the corresponding nanocomposite increased by 24.1% and 29.2% compared to the reference sample, respectively. The presence of OIB-POSS nanoparticles and their random distribution in the SBR matrix was confirmed by transmission electron microscopy. The crosslinking density of nanocomposites was calculated by the Flory-Rehner method and a decrease was observed with the addition of OIB-POSS nanoparticles. In addition, thermal aging process as 70 °C for 70 h was applied to vulcanized samples. It was noted that the mechanical properties of SBR/OIB-POSS nanocomposites remarkably improved, whereas their crosslinking densities gradually decreased after thermal aging.

Methacrylate-functionalized POSS influence on cross-linking and mechanical properties of styrene-butadiene rubber

The addition of methacrylate-functional polyhedral oligomeric silsesquioxane (MA-POSS) nanoparticles to styrene-butadiene rubber (SBR) composites was evaluated in terms of rheological, mechanical, and morphological properties. The aging process and cross-link density of rubber nanocomposites were examined in presence of MA-POSS. The MA-POSS could directly participate in the vulcanization reaction due to its methacrylate groups and its concentration affected the rheological and mechanical properties of rubber. The sulfur vulcanization characteristics of MA-POSS/SBR nanocomposites were determined by moving die rheometer. It was indicated that the addition of MA-POSS to SBR composites retarded the curing time and decreased the cross-link density. Due to an effective interaction between MA-POSS nanofiller and SBR matrix and excellent dispersion of POSS, the mechanical properties of nanocomposites were higher than those of the reference compound without MA-POSS. However, there was no significant change investigated in tensile retention in presence of MA-POSS. The presence and the random distribution of MA-POSS in SBR matrix was confirmed by TEM analysis. The cross-link densities of the composites, which were calculated using Flory–Rehner equation, decreased with increasing amount of POSS nanofiller. It was finally revealed that the thermal aging dramatically reduced the mechanical properties and cross-link density of MA-POSS/SBR nanocomposites.

The Effect of Network Structure on Compressive Fatigue Behavior of Unfilled Styrene-Butadiene Rubber

The effect of network structure on dynamic compressive fatigue behavior and static compressive mechanical properties of styrene-butadiene rubber (SBR) were investigated. A series of SBR compounds with different amounts of sulfur and dicumyl peroxide (DCP) were prepared, and their crosslinking densities were calculated using the Flory–Rehner equation. Compressive fatigue resistance and creep behavior of the vulcanizates were performed on a mechanical testing and simulation (MTS) machine. The fatigue damage surface of SBR vulcanizates before and after a dynamic compressive fatigue test was observed with a scanning electron microscopy (SEM). The results suggested that the surface of the samples was badly damaged as the number of compressive cycles increased. By comparison, compressive fatigue caused less surface damage to sulfur-cured SBR than to peroxide-cured SBR. The peroxide-cured SBR samples showed higher energy dissipation than sulfur-cured SBR during cyclic compression. The peroxide-cured SBR showed lower creep strain and compression set than the sulfur-cured SBR. The -Sx- linkages provided by the sulfur curing system allow dynamic compressive deformation but suffer from poor static compressive resistance. However, the carbon-carbon linkages from DCP are irreversible and provide higher resistance to static compressive stress, but they do not show obvious dynamic compressive fatigue resistance.

Mechanical, acoustical and flammability properties of SBR and SBR-PU foam layered structure

In this work a layer structure from styrene butadiene rubber (SBR) composites and PU foam with improved flame retardancy property and high sound absorption coefficient at frequency range (200–500 Hz). Different types of flame retardants; iron (acrylic-co-acrylamide) as metal chelate (MC), magnesium hydroxide (MOH) and sodium tripolyphosphate (STP) were blended with SBR. The type and loading level of flame retardant had a great effect on filler dispersion and consequently on mechanical properties of SBR. MOH exhibited the best dispersion as indicated from scanning electron microscope (SEM), and SBR/MOH samples had almost the highest crosslink density (16.04*10−5 g−1 mol) and the best mechanical properties where the tensile strength was improved by 32.7% at 40 phr MOH. Horizontal burning rate of SBR composites indicated that MC and MOH reduced the rate of burning of SBR at all loading levels. TGA data presented that the addition of flame retardants to SBR increased the maximum decomposition temperature in all composites. A double and triple layer structures of SBR composite and PU foam was designed. The effect of 2.5 cm air cavity on the sound absorption coefficient of SBR-PU foam layered structure was studied. The presence of air cavity behind the layered structure improved the sound absorption in the range of (200–500 Hz) better than the existence of it between the layers. The triple-layer structure gave higher sound absorption coefficient at lower frequencies than that obtained with the double-layer structure where it reached to ≥0.98 at 315 Hz.

Effect of Titanium Carbide as a Filler on the Mechanical Properties of Styrene Butadiene Rubber

For a few decades now, Styrene Butadiene Rubber (SBR) has been one of the highest volume general-purpose rubber owing to is low cost and better abrasion resistance compared to Natural Rubber. However, in recent times, some drawbacks have emerged and there has been a constant effort to improve its properties. The basic aim of this work is to study the effect of Titanium Carbide filler in powder form on the mechanical properties of SBR. The TiC amount is gradually varied as 0, 1, 2, 5, and finally 10 parts by weight per hundred parts of rubber [phr]. A practical study has been done on the physical and mechanical properties of SBR before and after addition of calculated amounts of TiC. The results obtained show that curing time continues to decrease with addition of TiC, while overall density continues to increase. Hardness, tensile strength and elastic modulus values showed an increase until 2% TiC, and then a subsequent reduction. Correspondingly, the % elongation decreased up to 2% TiC, and then increased slightly. Interestingly, it was observed that even small amounts TiC caused a significant increase (225% increase) in Tear strength, but there was no significant dependence on the amount of TiC. So, this work proves that by using 2% TiC, the mechanical properties can be increased up to greater extent at a reduced curing time.

A low-cost and high-value reinforcing filler for styrene butadiene rubber fabricated by a pneumatic separation technique from coal gasification fine slag

A novel filler for rubber was prepared by deep processing of coal gasification fine slag (CGFS) using an airflow sorter. Five processed CGFS samples with different sizes and carbon contents were obtained. The effects of particle size, unburned carbon, and surface properties of CGFS on the comprehensive properties of filled styrene butadiene rubber (SBR) were investigated. The mechanical properties were improved with decreasing CGFS size, and the curing and mechanical properties exhibited better performance owing to the unburned carbon. Unburned carbon can improve the dispersion properties of the filler and the compatibility between the matrix and filler. The best values for the curing characteristics and mechanical properties of SBR appeared when CGFS-S2 and CGFS-S3 were used as the fillers, respectively. Heavy calcium carbonate (CaCO3) particles were used as a comparative filler, and the results demonstrated that CGFS particles have the potential to replace CaCO3 in rubber. A novel method for preparing coal gasification fine slag (CGFS) samples utilized as a reinforcing filler for the SBR matrix through an efficient pneumatic separation technique has been demonstrated. The superior filler–rubber interfacial interaction can contribute to significant reinforcement in the comprehensive performances of composites by the addition of CGFS series fillers into the SBR matrix. CGFS particles have great potential for application in rubber composites, and a new strategy of using CGFS as fillers has been established.

Utilization of chrome-tanned leather wastes in natural rubber and styrene-butadiene rubber blends

Nowadays, the amount of chrome-tanned leather scraps from the leather industry is increasing rapidly due to diminishing interest in their utility in related areas. These kinds of wastes cause considerable negative, environmental effects, and therefore, producers should find new methods of recycling and/or disposal. It is speculated that leather scraps may be a valuable additive in rubber-based materials thanks to their similar elastic properties. In this study, chrome-tanned leather wastes have been incorporated into natural rubber and styrene-butadiene rubber and their blends in various ratios by using a Banbury mixer and two-roll mill, subsequently. Effects of the wastes on rheological, thermal, mechanical, aging, and morphological properties of the blends were investigated. Different penetration ability and distinct cure rates of the two rubbers caused interesting rheological characteristics. Original mechanical properties of styrene-butadiene rubber and its blends were retained after waste incorporation. Furthermore, thermal aging resistance of natural rubber matrix could be improved. The most significant effect of leather particles is the enhancement of the tear strength of all the vulcanizates by shifting the tear mechanism towards the tortuous fracture pathway.

Carbon nanotube/reduced graphene oxide hybrid for simultaneously enhancing the thermal conductivity and mechanical properties of styrene -butadiene rubber

A novel hybrid of polymer functionalized-carbon nanotube @ reduced graphene oxide (PCNT@RGO) was prepared by reversible addition-fragmentation chain transfer polymerization, esterification reaction and reduction process. PCNT@RGO hybrid as a filler can effectively enhance the thermal conductivity and mechanical properties of styrene-butadiene rubber (SBR) vulcanizate. Remarkably, the tensile strength and stress at 200% extension of the SBR vulcanizate reached as high as 8.8 and 7.7 MPa at PCNT@RGO loading of 3 wt%, increasing by approaching 203% and 450% compared with neat SBR. Furthermore, the vulcanizate also exhibited high thermal conductivity (0.45 W/m K), which is 2.0-fold higher than that of SBR. The improvement in properties could be attributed to the synergetic effect of PCNT and RGO in PCNT@RGO hybrid, strong interfacial between PCNT@RGO and SBR matrix, the large constrained regions and continuous filler networks. Such good performances render the SBR/PCNR@RGO composite appealing for the use in various engineering practices.

Experimental thermal transport evolution of silane activated nano-clay reinforced styrene butadiene elastomeric nanocomposites

In this study, silane activated nanoclay was reinforced in styrene butadiene rubber (SBR) to enhance the thermal resistance/stability and mechanical properties of SBR. silane activated nanoclay with variant concentrations was impregnated in the rubber matrix to fabricate polymer nanocomposites under control processing conditions. Experimental thermal transport, thermal oxidation, phase transition study, and mechanical properties of the nanocomposite specimens were carried out. Thermal insulation, thermal stability, and heat flow response were remarkably enhanced with the addition of nanokaolinite in the polymer matrix. Phase transition temperatures, their corresponding enthalpies, tensile strength, elastic modulus, elongation at break and hardness of the rubber composites were positively influenced with the filler incorporation into the host matrix. The Even dispersion of nanoreinforcements, morphological and compositional analyses of the thermal transport tested specimens were performed using scanning electron microscopy and energy dispersive spectroscopy, respectively.

Microbial desulfurization for ground tire rubber by mixed consortium-Sphingomonas sp. and Gordonia sp.

Sphingomonas sp., Gordonia sp. and their mixed consortium were used to desulfurize ground tire rubber (GTR), respectively. The microorganisms' growth characteristic was studied and desulfurization effect on GTR was evaluated systematically by measuring the water contact angle, swelling values, crosslink density and element content of rubber samples. Besides, the mechanical properties of SBR (styrene butadiene rubber) composite filled with GTR and DGTR (desulfurized ground tire rubber) were studied and the morphology of tensile fracture surface was observed. The results showed that the biomass of the mixed bacteria was higher than any single bacteria during co-culture desulfurization process, which indicated that these two kinds of bacteria can promote each other and grow together. After desulfurized by the mixed bacteria, the crosslink density of DGTR decreased by 9.5% and sulfur content on surface decreased by 32.4%, which changed more obvious than DGTR treated by single strain. Besides, the mechanical properties of SBR/DGTR composites were higher than those of SBR/GTR composites, and among all these SBR composites, the one filled with DGTR treated by the mixed bacteria had best mechanical properties. The interface coherence between DGTR and SBR matrix was enhanced, too. It indicated that these two kinds of bacteria can promote each other to grow together and get better desulfurization effect.

Preparation of silica-reinforced styrene–butadiene rubber via co-coagulation process

Styrene–butadiene rubber (SBR) was reinforced with silica (SiO2) by co-coagulating process. This study investigated the SiO2 amount, stirring time and pH value affecting the SiO2 content, curing characteristics and mechanical properties of SBR. Results showed that SiO2 content and reinforcing behavior were greatly influenced by the amount of SiO2 and pH value. The torque, tensile strength and elongation at break were optimal when the mass fraction of SiO2 was 21.5 wt%, stirring time was 6 h and pH value was 6.57. The utilized efficiency of SiO2 decreased with the increasing amount of SiO2 but increased with the increasing stirring time. The optimum cure time decreased with the increasing amount of SiO2. Both tensile strength and elongation at break decreased with the increasing pH value. Scanning electron microscopy observations showed that the SiO2 nanoparticles were distributed evenly in the SBR.

Processibility and Mechanical Properties of Mullite-Filled Styrene Butadiene Rubber Composites

Mullite (3A12O3·2SiO2) is an aluminosilicate ceramic of great technological importance. We investigated its potential as fillers in rubber. Mullites untreated or treated with 3% γ-mecapto-propyltrimethoxysilane (A-189) were added into styrene-butadiene rubber (SBR) materials on a laboratory-sized two-roll mill. For comparison, commercial precipitated silica was also used. The effect of these fillers on the cure characteristics, processibility and mechanical properties of SBR at various loadings, ranging from 0 to 50 phr was investigated. The results showed that mullite was a semi-reinforcing filler for SBR materials and exhibits better overall cure properties, lower Mooney viscosity, lower tensile set, better resilience as compared to precipitated silica, while it is inferior to precipitated silica especially with regard to tensile strength, tear strength and abrasion resistance. The presence of the silane coupling agent can enhance mechanical properties of filled SBR vulcanizates to some extent.

Effect of Fillers on Mechanical Properties of Dynamically Crosslinked Styrene Butadiene Rubber/High Density Polyethylene Blends

The effect of fillers on the mechanical properties such as stress— strain behavior, tensile strength, percentage strain at-break, Young's modulus and tear strength have been investigated. Different filled crosslinked thermoplastic elastomers of styrene butadiene rubber (SBR)/high density polyethylene blends (HDPE) blends were prepared using silica, HAF-carbon black, china clay and TiO2. The extent of polymer-filler interaction has been analyzed by Kraus as well as Cunneen—Russell equation. The reinforcement ability of the filler was increased in the order of silica>HAF-black>clay>TiO 2. The nature of the filler and filler loading has a dramatic effect on the mechanical properties of SBR/ HDPE blends. Filled blends showed improved mechanical properties such as enhanced of strain at-break, when fillers are incorporated. The initial trend of properties for all filled system is the enhancement of properties. When HAF-black is used as the filler, at higher loading strain at- break is found to decrease due to the stiffness of the matrix. In the case of clay, there is a deterioration of properties occurs on higher loading, which is attributed to dilution effect and all TiO 2 filled system have lower elongation at break than the base polymer. Theoretical models namely Guith's and Kerner's model have been compared with the experimental values of Young's modulus of filled system. The experimental values of modulus are found to be higher than the theoretical values indicating strong interaction between the filler and the matrix. SEM studies of the tensile and tear fractured surfaces of the filled blends have been carried out. The variation in properties was correlated with the morphology of the system.

The Effect of Silica Filler and Aging on Breakdown Voltage and Some Mechanical Properties of Styrene-Butadiene Rubber(SBR)/Silica

The Effect of Silica Filler and Aging on Breakdown Voltage and Some Mechanical Properties of Styrene-Butadiene Rubber(SBR)/Silica

Effect of new additives on the ultrasonic attenuation and mechanical properties of styrene–butadiene rubber

AbstractThe change in attenuation of longitudinal ultrasonic waves has been measured as a function of frequency and temperature for styrene–butadiene‐rubber (SBR) mixed with Ismacorr 141 as plasticizer and antioxidant. Analysis of the results showed relaxation processes and the activation energies for these processes were calculated and found to be related to the plasticization of samples. Also the velocity of the ultrasonic longitudinal waves through different samples was measured. The effect of Ismacorr 141 on the physical and mechanical properties of SBR was also studied.