Styrene-butadiene Rubber Rubber Research Articles

Characterization of recycled styrene butadiene rubber ground tire rubber: Combining X‐ray fluorescence, differential scanning calorimetry, and dynamical thermal analysis for quality control

ABSTRACTAppraisal of the main rubber characterization techniques for styrene butadiene rubber (SBR) was performed on standard SBR samples as well as recycled ground tire rubber (GTR) from an industrial tire recycling facility, containing a blend of SBR and natural rubber. The aim of the work was to provide additional information relevant to quality control in the field of rubber recycling. Benchmark characterization of industrial samples by inductively coupled plasma optical emission spectrometry, atomic absorption spectrometry, solid‐state proton nuclear magnetic resonance, and elemental (CHNS) analysis are reported. X‐ray fluorescence spectrometry is shown to be rapid and quantitative for determining the zinc content in an industrial context. Thermogravimetric analysis, already used to determine carbon black and inorganic material content in rubbers and GTR, is recommended for determination of monomer weight ratios of SBR sources not containing other rubbers, but not for GTR. Differential scanning calorimetry (DSC) measurements of the glass‐transition show that changes in monomer ratio affect glass‐transition temperature values, and therefore, DSC can be used to detect changes in rubber composition from batch to batch. These results show that DSC and X‐ray fluorescence spectroscopy characterization techniques can be used for GTR and may lead to more thorough and rapid quality control procedures of these complex samples. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42692.

Superhydrophobic and oleophobic surfaces obtained by graft copolymerization of perfluoroalkyl ethyl acrylate onto SBR rubber

Abstract Superhydrophobic and oleophobic rubbery coatings were prepared by spraying perfluoroalkyl ethyl acrylate (Zonyl TA-N) grafted styrene butadiene rubber (SBR) solution in toluene after addition of hydrophilic and hydrophobic fumed silica powders onto glass. Grafting onto SBR has been performed by free radical copolymerization in toluene using different Zonyl TA-N feed compositions. Molecular weights of the graft copolymers were determined by GPC and intrinsic viscosity measurements. Thin films of Zonyl TA-N grafted SBR copolymers were prepared by dip coating glass slides into toluene solutions of SBR- g -Zonyl TA-N with varying fluoromonomer contents and their surface free energies were determined by contact angle measurements. The increase in Zonyl TA-N content resulted in a considerable decrease of the total surface free energy of the grafted SBR film. Later, superhydrophobic and oleophobic surfaces were prepared by adding hydrophilic and hydrophobic fumed silica powders into graft copolymer solutions and spraying onto glass. The effect of the Zonyl TA-N content in the graft copolymer, type of silica and its weight concentration in the solution on the water and hexadecane contact angle values, on the surface morphology and mechanical durability of the coatings were investigated. The highest water contact angle of the SBR- g -Zonyl TA-N/SiO 2 hybrid coatings was determined to be 162° and hexadecane contact angle 147° after adjusting the silica type, solids content and fluoroacrylate/SBR composition of the graft copolymer spray solution.

Innovative neutron shielding materials composed of natural rubber-styrene butadiene rubber blends, boron oxide and iron(III) oxide

Optimized flexible and lightweight neutron shielding materials were designed using the Monte Carlo N-Particle (MCNP) code. Thicknesses of 10 mm and 100 mm were tested for neutron shielding performances. Simulation results indicated that the 10 mm shielding material of natural rubber (NR) and styrene butadiene rubber (SBR) blend (1:1) with 60 part per hundred rubber (phr) boron oxide (B2O3) and 100 mm shielding material with four alternating layers of NR with 100 phr iron (III) oxide (Fe2O3) and of NR and SBR blend (1:1) with 10 phr B2O3 were most suitable for thermal neutron shielding and all-energy neutron shielding, respectively. Experimental results verified the shielding efficiency of these optimal designs and ease of fabrication.

Proper use of rice straw black liquor: lignin/silica derivatives as efficient green antioxidants for SBR rubber

Purpose – The purpose of this paper is to study the efficiency of lignin/silica and calcium lignate/calcium silicate as natural antioxidants in styrene-butadiene rubber (SBR) vulcanizates. Design/methodology/approach – It has been found that thermal aging data of the aged sample revealed that SBR vulcanizate undergoes crosslink reactions that lead to embrittlement and ultimately failure. Incorporation of lignin/silica or calcium lignate/calcium silicate, however, resulted in significant improvement of the degradation profile of the vulcanizates at 90±1°C. Loss of tensile strength and flexibility during aging of the SBR compounds with 8 phr lignin/silica or calcium lignate/calcium silicate was mild relative to unfilled polymer, indicating a restricted degradation due to the presence of the investigated compounds. The results obtained revealed that the investigated compounds are good antioxidant, and the evaluation was confirmed by physico-mechanical properties of the vulcanizates, FT-IR spectroscopy, transmission (TEM) and scanning (SEM) electron microscope. Findings – It was noticed that SBR vulcanizates having 8 phr of lignin/silica or calcium lignate/calcium silicate exhibited the best mechanical properties in comparison with other concentrations (1, 2, 4, 6 and 10 phr). Also, results revealed that the lignin/silica derivatives are efficient antioxidants in SBR vulcanizates compared to vulcanizates containing conventional antioxidants used in rubber industry, namely polymerized 2,2,4-trimethyl-1, 2-dihydroquinoline (TMQ), and N-isopropyl-N'-phenyl-P-phenylenediamine (IPPD). Research limitations/implications – All these results indicated that lignin/silica and calcium lignate/calcium silicate in SBR had good heat resistance and aging resistance, calcium lignate/calcium silicate has an application limitation as not all vulcanizates need to use CaCO3/calcium salts. Practical implications – Lignin is usually seen as a waste product of pulp and paper industry and is often used as fuel for the energy balance of the pulping process. It is simple isolation along with silica from rice straw and using it as an antioxidant added further practical utility for this waste. Originality/value – The importance of lignin/silica derivatives is arisen from their biodegradability and their ease availability from rice straw black liquor.

The influence of the arrangement of styrene in methyl methacrylate/butadiene/styrene on the properties of PMMA/SAN/MBS blends

A series of methyl methacrylate-butadiene-styrene (MBS) core–shell impact modifiers were prepared by grafting styrene (St) and methyl methacrylate (MMA) onto polybutadiene (PB) or styrene-butadiene rubber (SBR) seed latex in emulsion polymerization. All the MBS modifiers were designed to have the same total chemical composition, and Bd/St/MMA equaled 39/31/30, which was a prerequisite for producing transparent blends with poly(MMA)/styrene-acrylonitrile (PMMA/SAN) matrix copolymers. Under this composition, different ways of arrangement for styrene in MBS led to the different structure of MBS modifier. The concentration of PB or SBR rubber of MBS in PMMA/SAN/MBS blends was kept at a constant value of 15 wt.%. The effects of arrangement of St in MBS on the mechanical and optical properties of PMMA/SAN/MBS blends were investigated. The results indicated that Izod impact strength of PMMMA/SAN/MBS blend with the amount of St grafted on core in MBS was higher than that of blend with the amount of St copolymerized with Bd in core of MBS, while the transparency of blend is opposite. From transmission electron microscopy, it was found that the arrangement of St in MBS influenced the dispersion of blend, which led to different toughness. Copyright © 2013 John Wiley & Sons, Ltd.

Effect of SBR Rubber Particle Size Distribution on Its Thermo-Mechano-Chemical Regeneration

Recycled Styrene-Butadiene Rubber (SBR) from ground tire rubber (GTR) was sieved into four granulometric fractions between 125 and 500 microns to determine the effect of particle size on its thermo-mechano-chemical regeneration in an internal batch mixer. Different temperatures (140-180°C) and rotor speeds (40-120 rpm) were imposed with and without the addition of a regeneration aid (aromatic oil). The results show that partial regeneration (lower crosslinking degree) is possible under specific thermo-mechanical conditions, but the addition of the aromatic oil has limited efficiency towards this regeneration.

Cure and mechanical properties and abrasive wear behavior of natural rubber, styrene–butadiene rubber and their blends reinforced with silica hybrid fillers

This work investigated the mechanical properties of natural rubber (NR), styrene–butadiene rubber (SBR) and NR/SBR blends filled with silica hybrid filler, and their abrasive wear behavior against different counterface materials. The silica hybrid filler included bagasse ash silica (BASi) and precipitated silica (PSi). The BASi content used was 0, 5, 10 and 15 phr, which was incorporated into rubber compounds filled with 20 phr PSi. The wear behaviors of NR, SBR and their blends were examined using an in-house built abrader in a pin-on-plate (POP) configuration; they were tested against various counterface materials, including steel, concrete, and fabric materials under dry and wet conditions. The results suggested that BASi could be used as co-reinforcing filler with PSi for SBR and NR/SBR compounds, resulting in an improvement in the dispersive and distributive properties of PSi agglomerates in the rubber matrix, as indicated by an increase in tensile strength and elongation at break. However, this was not the case for the NR system. The BASi/rubber composites demonstrated greater abrasive wear resistance against a fabric counterface than against steel and concrete counterfaces, respectively. In the case of a fabric counterface, the addition of BASi tended to greatly increase the specific wear rate of the rubbers due to the detachment of fabric and BASi particles acting as three-body abrasive wear. In addition, all rubber composites abraded against steel, concrete and fabric under wet conditions showed less wear than composites under dry condition, except for SBR rubber composites on a concrete counterface.

Effect of Modified Nano-Silica on the Reinforcement of Styrene Butadiene Rubber Composites

The performance of styrene butadiene rubber (SBR) composites filled with nano-silica has been improved by surface modification of the nano-silica using silane coupling agents. The dispersion of nano-silica in SBR rubber and the bonding force of nano-silica with SBR were significantly improved, and the physical and mechanical properties of the vulcanized rubber were greatly improved. The results showed Si69 (bis-(γ- triethoxysilylpropyl)-tetrasulfide) was the best modifier among the six silane coupling agents used in the experiments, and its optimum amount was 12% (wt) of nano-silica.

Migration of low molecular weight moiety at rubber–polyurethane interface: An ATR-IR spectroscopy study

In this study, a novel approach based on ATR-IR spectroscopy consisting in the combined use of two prisms of different nature and refraction index (germanium—about 1 μm depth and zinc selenide—about 3 μm depth) was proposed to study the polyurethane–rubber interface. More precisely, the migration of paraffin wax additive in as-received and MEK cleaned vulcanized styrene–butadiene rubber (SBR)–polyurethane coating interface was monitored. Polyurethane coating with thickness of about 2 μm was applied on the SBR rubber surface and the ATR-IR spectra were recorded in the polyurethane coating. Thus, the ATR-IR spectrum obtained with Ge prism analyzed only the polyurethane coating whereas the ATR-IR spectrum obtained with ZnSe analyzed both the polyurethane coating and the near surface SBR. The results obtained showed that the paraffin wax migrated from the SBR rubber bulk to the rubber–polyurethane interface, then diffused into the polyurethane and finally migrated to the polyurethane surface.

Synergic effect of N‐benzylimine aminothioformamide secondary accelerator during sulfur vulcanization of a styrene‐butadiene‐natural rubber blend

AbstractIn this study we reported synergic activity of a novel secondary accelerator N‐Benzylimine aminothioformamide (BIAT) along with tetramethylthiuram disulfide (TMTD) in improving cure and mechanical properties of gum and filled mixes of Styrene‐Butadiene Rubber (SBR). The feasibility of application of BIAT in sulfur vulcanization of an ideal blend of SBR and natural rubber (NR) has also been investigated. The mechanical properties like tensile strength, tear resistance, hardness, compression set, and abrasion loss were measured. Swelling values were also determined as a measure of crosslink densities of the vulcanizates. The binary accelerator system BIAT‐TMTD was found very effective in improving cure properties of the mixes of pure SBR and a 50/50 blend of SBR and NR.There was also found simultaneous improvement in mechanical properties of vulcanizates of both pure and blend. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

Aqueous chloramine diffusion into elastomers

AbstractAqueous chloramine diffusion into styrene butadiene rubber (SBR) and natural rubber was analyzed using approximate analytical and numerical solutions of Fick's second law of diffusion to develop long‐term mass intake prediction curves. Diffusion coefficients were calculated for 1 mg/L chloramine concentration at three temperatures (23, 45, and 70°C) and also for 23°C at three chloramine concentrations (1, 30, and 60 mg/L). The reasonableness of using increased temperature and/or chloramine concentration to accelerate the diffusion process to obtain long‐term information was discussed. For 1 mg/L chloramine concentration, the activation energy for the diffusion of chloramines into SBR and natural rubber were computed to be 51.13 and 77.29 kJ/mol, respectively. Also, concentration profiles were developed to understand the extent of penetration through the elastomer thickness over time and temperature. Considering the reports of elastomeric compound failure in chloramine disinfectant water distribution systems because of swelling, this study will be helpful in understanding the performance of the elastomeric compounds in the system. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010

Effect of treatment of Bis(3‐triethoxysilyl propyl)tetrasulfane on physical property of in situ sodium activated and organomodified bentonite clay – SBR rubber nanocomposite

AbstractThis study describes the effect of treatment of Bis(3‐triethoxysilyl propyl)tetrasulfane (silane coupling agent, Si69, TESPT) on in situ sodium activated, organo modified bentonite clay – styrene butadiene rubber (SBR) nanocomposite. transmission electron microscopy and Wide angle X‐ray diffraction indicated the intercalation as well as partial exfoliation in both the organoclay and silane treated organoclay compound. It was found that about 5% of silane with respect to clay was the optimum dose for the treatment. Around 15% improvement in tensile and tear strength was observed due to silane treatment. Silane treated organoclay exhibited substantial improvement of the fatigue life, compression set, and rebound property. A detailed study of physical property was carried out. A comparison with low and high structure carbon black filled compound was also carried out. It revealed that the silane treatment helped organoclay to achieve comparable property of the compound having equivalent carbon black loading. Probable mechanism of interaction of silane with clay has also been proposed. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010

Study of the properties of in-situ sodium activated and organomodified bentonite clay – SBR rubber nanocomposites – Part I: Characterization and rheometric properties

This paper presents a detailed characterization and rheometric property study of in-situ sodium activated, organomodified bentonite clay – styrene-butadiene rubber (SBR) nanocomposite. It was found that around 10 phr loading was the optimum level for maximum effect of the organo clay. The WAXD data indicated that at higher loading there was formation of agglomerations in the matrix. It was found that organo clay compound exhibited lower maximum torque in comparison to equivalent amount of carbon black loaded compound. The nanocomposites were also used for partial replacement of N330 carbon black in a highly black loaded compound. Part replacement of the carbon black with nano-clay reduced the maximum rheometric torque in comparison to the control compound. Detail study revealed that with slight modification of the curing package, similar rheometric properties can be obtained.

On the influence of CB loading on the creep and relaxation behavior of SBR and NBR rubber vulcanizates

It is well known that the time dependence behavior (creep and relaxation) of crosslinked rubber systems are influenced by the incorporation of particulate fillers. The influence of carbon black (CB) loading on the creep and relaxation behavior of styrene butadiene rubber (SBR) and nitrile-butadiene rubber (NBR) has been studied. Creep test is carried out at 3 different stress levels while the relaxation test is carried out at 100% strain. The obtained results of five different compositions for SBR and NBR with 0, 20, 30, 50 and 70 phr of CB were compared. It can be found that creep resistance increases as CB loading increases and stress level decreases, while as CB loading increases the relative modulus ( E( t)/ E(0)) and initial relaxation speed decrease.

Properties of Activated Carbon Blacks Filled SBR Rubber Composites

Rubber reinforcing carbon black N330 was treated by physical activation under CO2 to different degrees of burn-off. The mechanical properties indicating the reinforcement of SBR (Styrene-Butadiene Rubber) vulcanizates filled by activated carbon blacks, such as tensile strength, modulus at 300% strain and elongation at break were determined. During CO2 activation of fresh carbon blacks, the development of microporous structure caused an increase of extremely large specific surface area and the porosity turned out to be an increasing function of the degree of burn-off. The tensile strength and modulus at 300% of activated carbon blacks filled rubber composites were improved at lower loading ratios of 20 and 30 phr, but decreased drastically after 30 phr, which is considered that it might be difficult to get a fully dispersed rubber mixture at higher loading ratios for fillers having very large specific surface areas. However, the Electromagnetic Interference (EMI) shielding effectiveness of SBR rubber composites having activated carbon black at 74% yield were improved at a large extent when compared to those having raw carbon black and increased significantly as a function of increasing loading ratio. Keywords : Carbon black, CO2 activation, Rubber reinforcement, EMI shielding effectiveness

The influence of CB loading on thermal aging resistance of SBR and NBR rubber compounds under different aging temperature

Aging temperatures play important role in changing the mechanical behavior of rubber, so thermal aging test under different temperatures was carried out to investigate the effect of aging temperatures on the tension, compression and hardness properties of styrene butadiene rubber (SBR) and nitrile butadiene rubber (NBR) compounds filled with different carbon black (CB) loading. The obtained results of five different compositions for SBR and NBR with 0, 20, 30, 50 and 70 phr of CB were compared. The dependences of the mechanical properties on aging temperature and CB loading were found.

Effect of Composition on Adhesive Blends Consisting of Neoprene and Phenol-Cardanol-Formaldehyde Copolymer

This study is concerned with the adhesive properties of blends consisting of a copolymer phenolic resin and neoprene rubber. The phenolic resin is the condensation product of formaldehyde and a mixture of phenol and cardanol, a substituted phenol. Cardanol is the main ingredient of cashew nut shell liquid, a renewable resource and a cheap agro-by-product. The specific objective of the study is to arrive at optimum stoichiometric ratios between total phenol and formaldehyde (P/F ratio) so that the best peel and shear properties are obtained for aluminum-aluminum (Al–Al), styrene butadiene rubber-styrene butadiene rubber (SBR–SBR), and Al–SBR specimens. In general, the composition of the resin (represented by the P/F ratio) has only limited influence over the shear properties. Peel strength, on the other hand, is influenced by the P/F ratio. It is found to be a maximum for a P/F ratio of 1:1.5–1:1.7 for all cases. The results also prove that cardanol, a cheap renewable resource, can be a useful starting material for adhesive formulations.

A New Approach to Improved Properties of Rubber Vulcanizates Containing White Molybdates

ABSTRACT Incorporation of fillers in rubber results in a profound effect on rheological and mechanical properties of the formed composites. Fillers are customarily classified into organic and inorganic. The latter class includes calcium carbonate, talc, barium sulfate, kaolin, silica, etc. Molybdates are inorganic, nontoxic white pigments combined with reasonable pricing range and controlled solubility. The purpose of this study was to employ white molybdates and study their role as reinforcing fillers that can replace traditional carbon black, or semi-reinforcing furnance black (SRF), with both natural rubber (NR) and a blend of natural rubber-styrene butadiene rubber (NR-SBR), to show the modification of rheometric characteristics, tensile strength, strain at break, hardness, Young's modulus, swelling in toluene, thermal oxidative aging, and calculation of the rubber-filler interaction after the addition of such fillers.

Mechanical and flame‐retarding properties of styrene–butadiene rubber filled with nano‐CaCO3 as a filler and linseed oil as an extender

AbstractA nanosize CaCO3 filler was synthesized by an in situ deposition technique, and its size was confirmed by X‐ray diffraction. CaCO3 was prepared in three different sizes (21, 15, and 9 nm). Styrene–butadiene rubber (SBR) was filled with 2–10 wt % nano‐CaCO3 with 2% linseed oil as an extender. Nano‐CaCO3–SBR rubber composites were compounded on a two‐roll mill and molded on a compression‐molding machine. Properties such as the specific gravity, swelling index, hardness, tensile strength, abrasion resistance, modulus at 300% elongation, flame retardancy, and elongation at break were measured. Because of the reduction in the nanosize of CaCO3, drastic improvements in the mechanical properties were found. The size of 9 nm showed the highest increase in the tensile strength (3.89 MPa) in comparison with commercial CaCO3 and the two other sizes of nano‐CaCO3 up to an 8 wt % loading in SBR. The elongation at break also increased up to 824% for the 9‐nm size in comparison with commercial CaCO3 and the two other sizes of nano‐CaCO3. Also, these results were compared with nano‐CaCO3‐filled SBR without linseed oil as an extender. The modulus at 300% elongation, hardness, specific gravity, and flame‐retarding properties increased with a reduction in the nanosize with linseed oil as an extender, which helped with the uniform dispersion of nano‐CaCO3 in the rubber matrix. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 2563–2571, 2005

Adhesion strength study between plasma treated polyester fibres and a rubber matrix

In this work, the adhesion strength between poly(ethylene terephthalate) (PET) fibres and styrene-butadiene rubber (SBR) was studied. The effects of atmospheric plasma treatment, used to increase adhesion strength between PET fibres and the rubber matrix, were investigated and compared. It was confirmed that lubricants on the fibres caused a decrease in adhesion strength between the plasma treated reinforcing PET fibres and the SBR rubber matrix. These lubricants can be removed by acetone. When washed and treated in plasma, a substantial improvement in adhesion strength was observed. No ageing in air before combination with the rubber matrix was observed. This confirmed that the plasma streamers caused the creation of a new, relatively stable chemical species on the polymer surface. It suggests that the surface modification of PET fibres by plasma treatment at atmospheric gas pressure is a suitable and technologically applicable method for the improvement of adhesion strength of polyester reinforcing materials to rubber.