Styrene Butadiene Rubber Compounds Research Articles

Influence of the Polarity of the Plasticizer on the Mechanical Stability of the Filler Network by Simultaneous Mechanical and Dielectric Analysis.

Four styrene butadiene rubber (SBR) compounds were prepared to investigate the influence of the plasticizer polarity on the mechanical stability of the filler network using simultaneous mechanical and dielectric analysis. One compound was prepared without plasticizer and serves as a reference. The other three compounds were expanded with different plasticizers that have different polarities. Compared with an SBR sample without plasticizer, the conductivity of mechanically unloaded oil-extended SBR samples decreases by an order of magnitude. The polarity of the plasticizer shows hardly any influence because the plasticizers only affect the distribution of the filler clusters. Under static load, the dielectric properties seem to be oil-dependent. However, this behavior also results from the new distribution of the filler clusters caused by the mechanical damage and supported by the polarity grade of the plasticizer used. The Cole–Cole equation affirms these observations. The Cole–Cole relaxation time and thus, the position of maximal dielectric loss increases as the polarity of the plasticizer used is also increased. This, in turn, decreases the broadness parameter implying a broader response function.

The crosslinking and mechanical properties of SBR compounds with the addition of carburized pine nut cone ash

In this study, four different pulps were prepared by adding 0%, 5%, 10%, and 15% carburized pine nut cone ash to a reference rubber compound based on styrene butadiene rubber (SBR). After vulcanization, the hardness, density, tensile strength, percentage elongation, tearing strength, and crosslink density of the compound were measured. In addition, the effects of the crosslink density on the mechanical properties were examined. The properties of the carburized pine nut cone ash compounds were evaluated both among themselves and comparatively with the physical and mechanical properties of the reference compound. In addition, it increased the hardness as well as the crosslink density, and it was shown to provide advantages in terms of its density, tensile strength, tearing strength, and percentage elongation properties. Furthermore, the fracture surfaces of the compounds were characterized via scanning electron microscopy and energy dispersion spectroscopy to explain the change in mechanical properties.

Influence of benzyl esters of vegetable oils on curing, mechanical and dynamic properties of silica filled natural rubber and styrene-butadiene rubber compounds

Influence of benzyl esters of vegetable oils on curing, mechanical and dynamic properties of silica filled natural rubber and styrene-butadiene rubber compounds

Effect of mica powder-filled styrene-butadiene rubber compounds on crosslink density and mechanical properties

In this study, four different compounds were produced by adding different proportions of mica powder (0-5-10-20%) to styrene-butadiene rubber. After vulcanization, the crosslink density, hardness, density, tensile strength, elongation percentage, and tearing strength of the compounds were measured. In addition, the effects of crosslink density on mechanical properties were discussed. The physio-mechanical properties of the new compounds produced were compared both among them?selves and with the properties of the rubber being referenced. It was observed that increasing the crosslink density of mica powder provided an advantage in terms of hardness, tensile strength, tearing strength, and percentage elongation properties. To explain the changes in mechanical properties, the tensile fracture surfaces were determined by SEM and energy dispersive spectroscopy. In the light of the obtained results, it was determined that the use of carbon black could be reduced by using mica powder in the rubber industry.

Setting Relationships between Structure and Devulcanization of Ground Tire Rubber and Their Effect on Self-Healing Elastomers.

The use of devulcanized tire powder as an effective reinforcement in self-healing styrene-butadiene rubber (SBR) compounds has been investigated for the first time in this work. For this purpose, the evolution of the microstructure of the rubber from end-of-life tires (ELTs) was studied during granulation, grinding and devulcanization through an exhaustive characterization work in order to relate the final microstructure with the mechanical response of the repaired systems. Different morphologies (particle size distribution and specific surface area) obtained by cryogenic and water jet grinding processes, as well as different devulcanization techniques (thermo-mechanical, microwave, and thermo-chemical), were analyzed. The results demonstrated the key influence of the morphology of the ground tire rubber (GTR) on the obtained devulcanized products (dGTR). The predictions of the Horikx curves regarding the selectivity of the applied devulcanization processes were validated, thereby; a model of the microstructure of these materials was defined. This model made it possible to relate the morphology of GTR and dGTR with their activity as reinforcement in self-healing formulations. In this sense, higher specific surface area and percentage of free surface polymeric chains resulted in better mechanical performance and more effective healing. Such a strategy enabled an overall healing efficiency of more than 80% in terms of a real mechanical recovery (tensile strength and elongation at break), when adding 30 phr of dGTR. These results open a great opportunity to find the desired balance between the mechanical properties before and after self-repair, thus providing a high technological valorization to waste tires.

Unravelling the effect of healing conditions and vulcanizing additives on the healing performance of rubber networks

Self-healing rubbers have steadily been growing during the last decades. Various strategies have been studied to transform the vulcanized rubber into a reversible cross-linked network with multiple repair cycles. However, a detailed description on how the chemical constituents of a rubber formulation affect the healing properties of the vulcanizate is unknown and has not been reported until now. In this research, the individual effects of both the curing agent (sulfur and peroxide) and the activating complex (zinc oxide and stearic acid) have been assessed on the healing capability of a styrene-butadiene rubber (SBR) compound. The analysis of different healing conditions revealed that pristine materials should be subjected to the same thermal treatment as the healed samples to obtain scientifically sound values of the healing efficiency. Results also showed that each component affected the healing at different time scales, with the activating complex being responsible for the initial physical healing stage. Meanwhile, sulfur would act at later stages as dynamic healing moiety, enabling disulfide exchange reactions. In conclusion, the mechanical recovery of a rubber network can be potentially tailored depending on the relation between the chemical components of the rubber formulation.

Combinations of dual-function azide-containing crosslinkers with C-H insertion capabilities for polymeric elastomers with improved adhesion properties

The utilization of the noncatalytic C-H insertion capability of the nitrene intermediate of azide-containing compounds is proposed in this study for the clean fabrication of polymer-inorganic functional hybrid materials with elasticity and adhesion capabilities. For this purpose, a combination of dual-function azide-based crosslinkers composed of azidosilane (6-azidosulfonylhexyltriethoxysilane, AS) and diazide-based crosslinkers [tri(ethylene glycol)diazidoformate, GDAF] is attempted. AS affords good adhesion capability of polymer materials to OH-containing inorganic substrate/fillers, while GDAF undergoes a simultaneous C-H insertion reaction with polymer chains in bulk, affording enough crosslinking sites to improve elasticity. Through adjustments of the compositions and curing conditions, the styrene butadiene rubber compound with the proposed combination of crosslinkers exhibits good mechanical properties and excellent elasticity, as demonstrated by the low tension set value. The compound also exhibits improved adhesion capability on OH-containing silica, quartz and polyimide films, providing functional hybrid materials with an ideal combination of elasticity and adhesion capabilities suitable possibly for cutting-edge applications.

The role of reduced graphene oxide as a secondary filler in improving the performance of silica-filled styrene-butadiene rubber compounds

The role of reduced graphene oxide as a secondary filler in improving the performance of silica-filled styrene-butadiene rubber compounds

Influence of the Silica Specific Surface Area and Ionic Liquids on the Curing Characteristics and Performance of Styrene-Butadiene Rubber Composites.

In this work, we present the effect of silica’s specific surface area (180 m2·g−1 and 380 m2·g−1, respectively) on the crosslinking of styrene–butadiene rubber (SBR) composites, as well as their crosslink density and functional properties, such as thermal stability, damping behavior, resistance to thermo-oxidative aging, and tensile properties. Ionic liquids (ILs) with a bromide anion and different cations, i.e., 1-butyl-3-methylimidazolium (Bmi), 1-butyl-3-methylpyrrolidinium (Bmpyr), and 1-butyl-3-methylpiperidinium (Bmpip), were used to enhance the cure characteristics of SBR compounds and the functional properties of SBR vulcanizates. It was proven that apart from the silica’s specific surface area, the filler–polymer and filler–filler physical interactions have a significant impact on the vulcanization kinetics of silica-filled SBR composites. Additionally, the performed studies have shown that ILs positively affected the dispersion of silica’s particles and reduced their ability to form agglomerates in the elastomer matrix, which enhanced the functional properties of the SBR vulcanizates.

Zinc Complexes with 1,3-Diketones as Activators for Sulfur Vulcanization of Styrene-Butadiene Elastomer Filled with Carbon Black.

Zinc oxide nanoparticles (N-ZnO) and zinc complexes with 1,3-diketones of different structures were applied instead of microsized zinc oxide (M-ZnO) to activate the sulfur vulcanization of styrene-butadiene rubber (SBR). The influence of vulcanization activators on the cure characteristics of rubber compounds, as well as crosslink density and functional properties of SBR vulcanizates, such as tensile properties, hardness, damping behavior, thermal stability and resistance to thermo-oxidative aging was explored. Applying N-ZnO allowed to reduce the content of zinc by 40% compared to M-ZnO without detrimental influence on the cure characteristic and performance of SBR composites. The activity of zinc complexes in vulcanization seems to strongly depend on their structure, i.e., availability of zinc to react with curatives. The lower the steric hindrance of the substituents and thus the better the availability of zinc ions, the greater was the activity of the zinc complex and consequently the higher the crosslink density of the vulcanizates. Zinc complexes had no detrimental effect on the time and temperature of SBR vulcanization. Despite lower crosslink density, most vulcanizates with zinc complexes demonstrated similar or improved functional properties in comparison with SBR containing M-ZnO. Most importantly, zinc complexes allowed the content of zinc in SBR compounds to be reduced by approximately 90% compared to M-ZnO.

Highly epoxidized soybean oil in replacement of mineral oil for high performance on silica-filled tread rubber compounds

The potential replacement of a treated residual aromatic extract mineral oil (TRAE) by a highly epoxidized soybean oil (ESO) into a silica-filled styrene-butadiene rubber compound was investigated. In order to determine if ESO compounds performance are suitable for tread tire applications, processing properties cure and characteristics were evaluated. The impact of ESO amount on the silica dispersion was confirmed by Payne Effect. The presence of chemical or physical interactions between ESO and silica improves the filler dispersion, enabling the compound processability and affecting the cure kinetic rate. An adjusted rubber compound with 2 phr of ESO and 2 phr of sulfur presented the higher stiffness and strength values with lower weight loss from a wear test compared with TRAE compound at an equal amount of oil and curing package. Furthermore, wet grip and rolling resistance predictors of both compounds gave comparable results, maintaining a better performance and reducing the dependence of mineral oil for tire tread compounds.

Compressive Fatigue Behavior of Gum and Filled SBR Vulcanizates.

The influence of carbon black on physical mechanical properties, compressive fatigue life, and the temperature changes during compression fatigue process of styrene-butadiene rubber (SBR) vulcanizates were explored. A series of unfilled and filled SBR compounds were prepared, and the compressive fatigue behaviors of the vulcanizates were performed on a mechanical testing and simulation (MTS) machine. The top surfaces of the filled SBR were imaged using scanning electron microscopy (SEM) after 105 cycles of compressive fatigue. The filled SBR shows greater compressive fatigue resistance than the unfilled SBR. The incorporation of carbon black into SBR improves the creep resistance. The best compressive fatigue resistance for the filled SBR was achieved by the addition of 30 phr carbon black. With the increase of carbon black content, the energy dissipation and the heat build-up increase simultaneously. Furthermore, SEM images of the vulcanizates suggest that the crack propagation mechanism of the unfilled and the filled SBR was different. For the unfilled SBR, due to periodical compressive stress, the polymer chains can be destroyed, and the cracks can be easily initiated and propagated, showing serious damage on the top surfaces of the specimen. However, for the filled SBR, the carbon black agglomeration around the cracks can greatly delay the generation of the cracks, decrease the fatigue damage, and ultimately improve the fatigue resistance.

Mechanical and thermal performances of rubber/graphite-derivatives: facile synthesis, characterization and formulation

A larger scale production of graphene oxide (GO), reduced graphene oxide (rGO) and reduced GO decorated with SiO2 (rGO@SiO2) as graphite-derivatives are reported. The pristine graphite (Gt), synthesized rGO and rGO@SiO2 were dispersed in dioctyl phthalate (DOP) assisted using sonication technique. styrene butadiene rubber (SBR)-based elastomer was first formulated and the homogenized samples are loaded into the SBR polymer matrix using a Bunbury-type kneader. Common industrial-grade materials were used to synthesize additives and compound formulations, and loading the additives into the polymer was mechanically performed. From an economic point of view, it means this product could be easily commercialized. Fourier-transform infrared spectroscopy (FTIR) spectrum index bands of prepared GO and rGO@SiO2 were appeared at about 1725 and 1064 cm-1, respectively. X-ray diffraction (XRD) was used to study the crystal structure of the synthesized materials. Surface morphology of the synthesized materials and separation of pristine graphite compressed layers were verified with Transmission Electron Microscopy (TEM) images. Mechanical testes of the compounded products were showed good tensile stress, virtually two folds greater than blank rubber. Thermogravimetric analyses investigation showed that a clear improvement of thermal stability of composites increased with adding the synthesized carbon-based additives. The prepared rGO/SBR and rGO@SiO2/SBR composites exhibited higher oxidative-induction time (13.84 and 9.39 min, respectively) compared with blank SBR compound.

Mechanical and dynamic properties of composite rubber (RSS and SBR) with waste rubber crumb and copper fiber

Waste rubber tire is difficult to decompose by nature, but it can be reused as a part of composite rubber materials. In this research, waste rubber crumb was mixed into Ribbed Smoked Sheets (RSS) and Styrene-Butadiene Rubber (SBR) compound to form a composite rubber. The aim of this research is to investigate the mechanical and dynamic properties of RSS and SBR compounds with waste rubber crumb and copper fibber. For this purpose, another composite material in the form of copper fiber is also added which is expected to increase the damping properties of the rubber even though the mechanical properties of the rubber will decrease. RSS and SBR rubber compounds consist of 25-phr and 50-phr waste rubber crumb. Waste rubber crumb is taken from used vehicle tires with the granular size passes through the mesh sieve number # 100. 5-phr, 10-phr, 20-phr, and 30-phr of copper fibers were added into 25-phr and 50-phr respectively. The copper fiber used is 0.3 ± 0.05 mm in diameter and length to diameter ratio is 40. The results of this study indicate that the addition of waste rubber 25-phr and 50-phr decreases the tensile strength, elastic modulus, and shear modulus but increases the damping properties. The addition of copper fiber 5-phr until 30-phr decreses the tensile strength and elastic modulus but increases the shear modulus and the damping properties.

Road to Increased Tire Sustainability: Carbon Black Replacement in Styrene Butadiene Rubber Compounds using Eco-Friendly Fillers

Road to Increased Tire Sustainability: Carbon Black Replacement in Styrene Butadiene Rubber Compounds using Eco-Friendly Fillers

The Carbon Black-Loaded Styrene-Butadiene Rubber in The Addition of Palmitamide: The Cure Characterization

This study investigated the influences of palmitamide on the cure characterization of carbon black (CB)-loaded styrene-butadiene rubber (SBR). The SBR was loaded with CB at a fixed loading (thirty phr) and the palmitamide was loaded into the CB-loaded SBR compounds with varied doses from two to eight phr. The palmitamide was prepared from the chemical reaction between urea and palmitic acid at an appropriate condition of reaction. The influences of palmitamide additions on the scorch time, cure time and cure rate index/CRI of CB-loaded SBR were investigated. It was examined that the palmitamide caused an enhancement in the rate of the cure process on the SBR compounds. The palmitamide decreased both the times to scorch and cure times but increased the CRI. The bigger the palmitamide doses caused in the lower were the scorch and cure times but caused in the higher was the CRI. The enhancement in CRI was attributed to the role of palmitamide as the supplementary accelerator for the CB-loaded SBR compounds. The amine content of palmitamide enhanced the CRI.

The incorporations of palmitamide as a rubber chemical into carbon black-loaded styrene-butadiene rubber: cure rate index and torque properties

This study studied the effect of palmitamide as a new rubber chemical on the index of healing rate and torsion properties of carbon black (CB) (CB) charged styrene-butadiene rubber compounds. SBR was loaded with CB at a fixed load (thirty phr) and palmitamide was added to the CB-loaded SBR compound at doses varying from two to eight phr. The effect of palmitamide addition on the healing rate index and torsional properties of SBR CB loads were investigated. It was revealed that palmitamide caused an increase in the speed of the healing process in SBR containing CB. The greater the palmitamide dose, the higher the CRI. The increase in CRI is associated with the role of palmitamide as an additional accelerator for CB-loading SBR. The amine content of palmitamide increases CRI. It was also revealed that palmitamide lowers the minimum torque but increases the maximum torque as well as the torque difference by up to six palmitamide additions. The minimum torque reduction is due to the plasticizing effect of palmitamide. The increase in maximum torque and difference in torque is due to the increased intercalation process due to the action of palmitamide as an acting agent which increases CB dispersion.

Effect of Sulfur Variation on the Vulcanizate Structure of Silica-Filled Styrene-Butadiene Rubber Compounds with a Sulfide-Silane Coupling Agent.

The vulcanizate structure of filled compounds is affected by filler–rubber interactions (FRI) and the chemical crosslink density (CCD) of the matrix rubber. In particular, in filled compounds using a silica–silane system, FRIs due to silica–rubber coupling are a major influencing factor for the vulcanizate structure and physical properties. In this study, the effect of sulfur variation on the vulcanizate structure of silica-filled solution styrene–butadiene rubber compounds using a sulfide–silane coupling agent was studied. The vulcanizate structure according to sulfur variation was quantitatively analyzed using the swelling test and Flory–Rehner and Kraus equations. As the sulfur content increased, both FRI and the CCD increased, and it was confirmed that sulfur variation influenced the silica–rubber coupling efficiency through increased FRI. In addition, field emission scanning electron microscope images showed that increased FRI contributed to improvements in silica dispersion, abrasion resistance, and energy loss characteristics.

Insights into the Payne Effect of Carbon Black Filled Styrene-butadiene Rubber Compounds

As a widely used reinforcing filler of rubber, carbon black (CB) often enhances the nonlinear Payne effect and its mechanism still remains controversial. We adopt simultaneous measurement of rheological and electrical behaviors for styrene-butadiene rubber (SBR)/CB compounds and CB gel (CBG) during large deformation/recovery to investigate the contribution of conductive CB network evolution to the Payne effect of the compounds. In the highly filled compounds, the frequency dependence of their strain softening behavior is much more remarkable than that of their CB network breakdown during loading, while during unloading the unrecoverable filler network hardly affects the complete recovery of modulus, both revealing that their Payne effect should be dominated by the disentanglement of SBR matrix. Furthermore, the bound rubber adjacent to CB particles can accelerate the reconstruction of continuous CB network and improve the reversibility of Payne effect. This may provide new insights into the effect of filler network, bound rubber, and free rubber on the Payne effect of CB filled SBR compounds.

Enhancing the Properties of Styrene-Butadiene Rubber by Adding Borax Particles of Different Sizes

In this research study, borax particles with different average sizes (1.25, 0.75, 0.60 μ m) were added to a styrene-butadiene rubber compound for reinforcement. This rubber has low mechanical, thermal and surface properties, as well as a low resistance to organic solvents. A laboratory two-roll mill was used at room temperature to add the borax particles to the synthetic rubber, then the rheometer characteristics such as torque, scorch time and cure time were limited at a temperature of 150°C. The results showed that the torque and CRI (curing rate index) improved by 160% for torque and 600% for CRI respectively, dependent on reducing the particle size from 1.25 μm to 0.6 μm. The surface properties shown by FE-SEM, AFM images, and FTIR analysis indicated a good dispersion of borax particles with an absence of the aggregates when a low borax particle size of 0.6 μm was used. Furthermore, the properties of tensile strength, elongation at break, and the hardness of the rubber compound were improved by 220% for tensile strength, 37% for hardness, and the reduction in elongation at break improved by 25% depending on the reduction in particle size. On the other hand, the resistance of the rubber compound to flame improved, besides the improvement of the thermal conductivity with decreasing particle sizes. The resistance of the rubber compound to organic solvents, such as toluene, was also improved, which was represented by the properties of swelling, the percentage of swelling index, and the cross-link density with 1.07% for swelling index and 1.3×10-3 mole/cm3 for cross-link density.