Neat Styrene-butadiene Rubber Research Articles

Impact of fiber coating with hydrophobic nanoparticles polymer on the physicomechanical properties of Pisum sativum L. fibers/ styrene butadiene rubber ecofriendly composites

Hydrophobic nanoparticle copolymers of vinyl acetate and different ratios of veova10 were used to coat Pisum sativum L. fibers (PSF). The impact of coating process on the reinforcement efficiency of PSF of styrene butadiene rubber (SBR) was investigated. The morphology study, indicated that, the coating with hydrophobic nanoparticle copolymers improved the interfacial adhesion between the PSF and SBR. The tensile strength (TS) of the composites containing coated fibers recorded the highest tensile properties, the lowest Mullins effect and the highest resistance to water absorption. The coating process improved the TS of PSF/SBR composite up to 35.3% after incorporation of 10 phr of coated PSF. The PSF/SBR composite containing 20 phr of coated fibers recorded water uptake of 14.18% compared to 23.24% for composites containing uncoated fibers. The PSF/SBR composites exhibited more biodegradation rate than that of neat SBR. The results indicated that the PSF coated with the prepared hydrophobic polymers had a beneficial impact on the physicomechanical properties of the PSF/SBR composites.

Preparation of natural bio-based Eucommia ulmoides gum/styrene-butadiene rubber composites and the evaluation of their damping and sound absorption properties

To achieve effective sound absorption in wide frequency bands under high pressures, Eucommia ulmoides gum (EUG) as one of the natural biopolymers was incorporated into styrene-butadiene rubber (SBR) to prepare sound absorption materials. The morphology, crystalline structure, and macro-performance (damping, sound absorption, and mechanical properties) of the as-produced composites were systemically investigated. When the EUG content was less than 30 phr, the EUG was dispersed in the SBR matrix as nanocrystallites primarily existed in the β-crystal form, which is demonstrated by wide-angle X-ray diffraction (WAXD) and polarizing microscope (POM). The dynamic mechanical thermal analyzer (DMA) results expressed that EUG had two dynamic mechanical loss peaks, i.e. the glass transition peak (Peak 1, -60–40°C) and melting transition peak (Peak 2, 30–60°C). Thus, the addition of EUG improved the damping performance of the composites in high-temperature areas to some extent. Moreover, in comparison to the neat SBR, the average sound absorption coefficient of SBR/EUG (70/30) composite increased by 24.23% in the frequency range of 3–8 kHz under 2.5 MPa, which show the excellent sound absorption properties. And since the EUG nanocrystallites played the role of physical crosslingking points, the SBR/EUG (70/30) composite also had outstanding comprehensive mechanical properties. The SBR/EUG composites may be applied to underwater sound absorption materials.

Improving Mechanical Properties and Thermal Conductivity of Styrene-Butadiene Rubber via Enhancing Interfacial Interaction Between Rubber and Graphene Oxide/Carbon Nanotubes Hybrid

To fully utilize the fascinating comprehensive properties of graphene oxide (GO) and carbon nanotubes (CNTs), GO was used to promote the dispersion of carboxylated multi-walled carbon nanotubes (CC) in rubber matrix. Additionally, carboxylated acrylonitrile butadiene rubber (xNBR) was used to enhance the interfacial interaction between the styrene-butadiene rubber (SBR) and the GO/CC hybrid fillers for the formation of hydrogen bonds between the oxygenated functional groups of GO/CC hybrid fillers and the carboxyl groups of xNBR. Moreover, the interfacial interaction was investigated by Fourier transform infrared spectroscopy and further proved by differential scanning calorimetry. As a result, the mechanical property and thermal conductivity of SBR composites were improved significantly compared with the neat SBR vulcanizate, which were much higher than those of the SBR composites without xNBR. In contrast to adding GO/CNTs directly to the rubber matrix, enhancing the interfacial interaction between GO/CC hybrid fillers and rubber matrix as demonstrated herein is a valuable strategy to prepare rubber composites with remarkable comprehensive properties.

Rational design of multifunctional properties for styrene-butadiene rubber reinforced by modified Kevlar nanofibers

In this work, a facile and effective approach is developed to obtain the water-dispersible Kevlar nanofibers (KNFs) by modifying KNFs with the assistance of epichlorohydrin (ECH). And the ECH-modified KNFs (m-KNFs) are firstly utilized to prepare styrene–butadiene rubber (SBR)/m-KNFs nanocomposites through latex co-coagulation method. The multifunctional properties of SBR/m-KNFs nanocomposites are thoroughly investigated. It is confirmed that m-KNFs have strong interactions with SBR via π-π stacking, which can generate huge enhancement on the performance of SBR nanocomposites. For example, the tensile strength, tear strength and the maximum decomposition temperature of SBR filled with 7 phr (parts per hundred rubber) m-KNFs are increased by 576%, 202% and 13.1 °C, respectively, compared with those of neat SBR. Meanwhile, the presence of m-KNFs has also improved the dielectric constant of SBR nanocomposites. This work provides a new insight into the fabrication of multifunctional KNFs-based rubber composites.

Stimuli‐responsive polymer nanocomposites based on styrene‐butadiene rubber and bacterial cellulose whiskers

Water‐induced mechanically adaptive rubber nanocomposites were prepared by mixing bacterial cellulose whiskers (BCWs) suspension with styrene‐butadiene rubber (SBR) latex, followed by evaporation method. The structure, morphology, dynamic mechanical properties, water stimuli‐responsive behavior, and biodegradability of SBR/BCWs nanocomposite films were investigated. The results showed that the hydrophilic whiskers had a significant reinforcement effect on the storage modulus of SBR matrix, which originated from the formation of a rigid three‐dimensional filler network within matrix by strong hydrogen bonding between whiskers. The SBR/BCWs nanocomposites showed pronounced water stimuli‐responsive behavior compared with neat SBR. The storage modulus of SBR/BCWs nanocomposite could be decreased by 99.2% after equilibrium water swelling. This remarkable water‐triggered modulus change is attributed to the disentanglement of BCWs network via competitive hydrogen bonding with water.

Impact of various oxidation degrees of graphene oxide on the performance of styrene–butadiene rubber nanocomposites

In this work, graphene oxide (GO) with various oxidation degrees were synthesized by adjusting the dosage of oxidation agent based on a modified Hummers' method, and were then used for the fabrication of the styrene–butadiene rubber (SBR)/GO nanocomposites through latex coagulation method, followed by a high‐temperature cure process. The vulcanization characteristics, thermal stability, mechanical properties, thermal conductivity as well as solvent resistance of SBR/GO nanocomposites were investigated. The results indicated that various surface structures of GO due to oxidation degrees may lead to different dispersion states of GO in the rubber matrix, and thus greatly influenced the cure rate, mechanical properties as well as thermal conductivity of SBR/GO nanocomposites. The optimal (moderate) oxidation degree of GO was achieved at the oxidation agent (KMnO4)/graphite weight ratio 9/5, for which case the tensile strength, tear strength, and thermal conductivity of SBR/GO nanocomposites increased by 271.3%, 112.3%, and 28.6%, respectively, compared with those of neat SBR. In addition, the mentioned nanocomposites also showed the best solvent resistance in toluene. POLYM. ENG. SCI., 58:1409–1418, 2018. © 2017 Society of Plastics Engineers

Improving thermal conductivity of styrene-butadiene rubber composites by incorporating mesoporous silica@solvothermal reduced graphene oxide hybrid nanosheets with low graphene content

Styrene-butadiene rubber (SBR) composites with enhanced thermal conductivity (TC) were prepared, by incorporating mesoporous silica@reduced graphene oxide (mSiO2@rGO) hybrid nanosheets. The mSiO2@rGO with sandwich structure is composed of rGO (0.50 wt%) coated with mSiO2. The sandwich and mesoporous features of mSiO2@rGO were clearly characterized. Compared to rGO and mSiO2, the mSiO2@rGO shows synergistic effects on TC enhancement. The incorporation of 3 per hundred rubber (phr) mSiO2@rGO increased the TC of SBR composites to 0.424 Wm−1K−1, which was about 183% of the TC of neat SBR (0.232 Wm−1K−1). Moreover, compared to the reported silica@graphene hybrid, mSiO2@rGO has mesoporous framework with pore sizes about 8.9 nm. The mSiO2 coating on rGO acts as functional block which could impede the aggregation of rGO, decrease the modulus mismatch between rGO and SBR, and increase the interface interaction between rGO and SBR.

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.

Ionic liquid functionalized graphene oxide for enhancement of styrene‐butadiene rubber nanocomposites

Ionic liquid 1‐allyl‐3‐methyl‐imidazolium chloride (AMICl) is used to fine‐tune the surface properties of graphene oxide (GO) sheets for fabricating ionic liquid functionalized GO (GO‐IL)/styrene‐butadiene rubber (SBR) nanocomposites. The morphology and structure of GO‐IL are characterized using atomic force microscope, X‐ray diffraction, differential scanning calorimetry, X‐ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, UV‐vis spectra and Raman spectra. The interaction between GO and AMICl molecules as well as the effects of GO‐IL on the mechanical properties, thermal conductivity and solvent resistance of SBR are thoroughly studied. It is found that AMICl molecules can interact with GO via the combination of hydrogen bond and cation–π interaction. GO‐IL can be well‐dispersed in the SBR matrix, as confirmed by X‐ray diffraction and scanning electron microscope. Therefore, the SBR nanocomposites incorporating GO‐IL exhibit greatly enhanced performance. The tensile strength, tear strength, thermal conductivity and solvent resistance of GO‐IL/SBR nanocomposite with 5 parts per hundred rubber GO‐IL are increased by 505, 362, 34 and 31%, respectively, compared with neat SBR. This method provides a new insight into the fabrication of multifunctional GO‐based rubber composites. Copyright © 2016 John Wiley & Sons, Ltd.

Constructing a segregated graphene network in rubber composites towards improved electrically conductive and barrier properties

A simple and effective approach, i.e. pre-construction method, was developed to fabricate a three-dimensional segregated graphene network (IL-3DGE) in a styrene butadiene rubber (SBR) matrix. Such segregated 3D-GE network dramatically enhanced the electrical conductivity, mechanical properties and gas barrier property of SBR composites. With the incorporation of 1.66 vol% IL-3DGE, the electrical conductivity of the composites was significantly enhanced by 10 orders of magnitude, the tensile strength was increased by 516%, and gas permeability was effectively reduced by 75.5%, as compared with those of neat SBR. Specifically, SBR/IL-3DGE with a segregated morphology showed a much low electrical percolation threshold (0.39 vol%), which is approximately 9-fold lower than that of the non-segregated SBR/IL-GE (3.78 vol%). The excellent properties of the composites were attributed to the construction of a 3D segregated conductive structure and strong interfacial interactions. This work provides a new insight into the fabrication of high-performance rubber composites for versatile practical applications.

Scalable fabrication of thermally conductive elastomer/boron nitride nanosheets composites by slurry compounding

So far, most of the preparation methods for polymer/boron nitride nanosheets (BNNSs) composites are not suitable for mass production. Here, cost-effective and environmentally friendly water/ethanol were selected as the solvents to prepare BNNSs slurry on large scale by liquid exfoliation/solvent exchange. The slurry was then compounded with styrene-butadiene rubber (SBR) to form the rubber/BNNSs composites via conventional two-roll milling. The sulfide-containing silane was introduced to modify the interface between BNNSs and the rubber. The silane modified BNNSs (Si-BNNSs) has been characterized by FTIR, XPS and TGA. It is found that, with in situ modification of the silane, the rubber/BNNSs composites exhibited significantly improved thermal conductivity. With 10.5 vol% Si-BNNSs incorporated, the thermal conductivity of the composites is increased by 253%, comparing to the neat SBR. Meanwhile, the mechanical properties of the composites are simultaneously largely enhanced. The scalable yet environmentally-friendly slurry approach paves the way for industrial-scale utilization of BNNSs in thermally conductive polymer composites.

Auxetic Nanocomposite based on Styrene Butadiene Rubber (SBR) Foam with Varying Nano-carbon Loading

Styrene-butadiene rubber (SBR) is a synthetically produced general-purpose rubber which is fabricated by copolymerization of styrene and butadiene. It is widely used in automobile tires owing to its good abrasion-resistance, enhanced crack resistance, and improved aging properties. Strength of SBR is improved by reinforcing it using fillers such as carbon black. Presence of gaseous phase in foamed structure of SBR increases volume along with improvement in various matrix characteristics. SBR matrix was transformed into foamy product during curing in the presence of chemical blowing agents. This paper presents preparation and characterization of SBR foam with varying nano-carbon loading causing development of a variety of foamy structures; processes like compounding and vulcanization altered the mechanical properties to a great extent. Mechanical characterization revealed that incorporation of 20% carbon in the SBR caused 140% rise in tensile strength and 90% increase in hardness with a corresponding decrease in elongation to about 35%, compared with neat SBR. The 'cure rate index' increased to 200% with 20% carbon concentration, whereas 'loss modulus' and 'tan δ' increased to 135% and 80%, respectively, as determined at maximum viscosity. Overall a significant improvement in mechanical properties and damping characteristics was observed.

Maleated high oleic sunflower oil‐treated cellulose fiber‐based styrene butadiene rubber composites

Surface treatment of cellulose fibers was performed with maleated high oleic sunflower oil (MSOHO). The MSOHO‐treated cellulose fibers and unmodified cellulose fibers were dispersed in styrene butadiene rubber (SBR) using a two roll mill. Vapor grown carbon nanofibers (VGCNF) were also incorporated at only one parts per hundred rubber (phr) in unmodified cellulose fibers/SBR composites. The curing characteristics, mechanical properties, and water absorption of the resulting composites were determined. MSOHO‐treated fibers completed curing at much slower rate and also decreased the cure density of composites, compared to unmodified fibers. In contrast, the combination of VGCNF and unmodified cellulose fibers accelerated the SBR curing process, but reduced the cure density. MSOHO treatment improved the dispersion of the fibers in the SBR, which resulted in improved mechanical properties of composites. The composite incorporating 1 phr VGCNF and 15 phr unmodified cellulose fibers showed the greatest increase in tensile strength as compared with neat SBR. POLYM. COMPOS. 37:1113–1121, 2016. © 2014 Society of Plastics Engineers

Water-Responsive Mechanically Adaptive Nanocomposites Based on Styrene–Butadiene Rubber and Cellulose Nanocrystals—Processing Matters

Biomimetic, stimuli-responsive polymer nanocomposites based on a hydrophobic styrene-butadiene rubber (SBR) matrix and rigid, rod-like cellulose nanocrystals (CNCs) isolated from cotton were prepared by three different approaches, and their properties were studied and related to the composition, processing history, and exposure to water as a stimulus. The first processing approach involved mixing an aqueous SBR latex with aqueous CNC dispersions, and films were subsequently formed by solution-casting. The second method utilized the first protocol, but films were additionally compression-molded. The third method involved the formation of a CNC organogel via a solvent exchange with acetone, followed by infusing this gel, in which the CNCs form a percolating network with solutions of SBR in tetrahydrofuran. The thermomechanical properties of the materials were established by dynamic mechanical thermal analysis (DMTA). In the dry state, all nanocomposites show much higher tensile storage moduli, E', than the neat SBR or the SBR latex. E' increases with the CNC content and depends strongly on the processing method, which appears to influence the morphology of the SBR nanocomposites produced. The highest E' values were observed for the solution cast samples involving an SBR latex, where E' increased from 3 MPa for the neat SBR to ca. 740 MPa for the nanocomposite containing 20% v/v CNCs. Upon submersion in deionized water, a dramatic reduction of E' was observed, for example from 740 to 5 MPa for the solution-cast nanocomposite containing 20% v/v CNCs. This change is interpreted as a disengagement of the percolating CNC network, on account of modest aqueous swelling and competitive hydrogen bonding of water molecules with the CNCs. It is shown that the method of preparation also influenced the swelling behavior and kinetics of modulus switching, consistent with different arrangements of the CNCs, which serve as channels for water absorption and transport within the hydrophobic SBR matrix.

PREPARATION AND PROPERTIES OF STYRENE-BUTADIENE RUBBER/CLAY NANOCOMPOSITES BY USING LIQUID RUBBER/CLAY MASTER BATCHES

ABSTRACT Rubber/clay nanocomposites (RCNs) have many applications because of their improved properties. The dispersion of clay in a rubber matrix, which plays an important role in the properties of RCNs, is a challenge. In this article, a solvent-free approach to produce the styrene butadiene rubber (SBR)/clay nanocomposites by using liquid rubber/clay master batches was introduced. The liquid/rubber master batches were first prepared using a high-speed centrifugal mixer and then compounded with neat SBR using conventional rubber compounding equipment. Compared with the composites prepared by melt mixing, this approach resulted in a better dispersion of the clay in the rubber matrix and improvements in tensile strength (4.98 MPa at 10 phr clay loading) and elongation at break (>1000% at 10 phr clay loading). The improved dispersion was confirmed by X-ray diffraction. The effect of clay loading on the tensile properties, dynamic mechanical properties, and the Payne effect was also investigated. The increase in clay loading resulted in a steady increase in the tensile properties up to a loading of 15 phr. The reinforcement in the RCN modulus using clay was compared with five models, including the Guth and Halpin-Tsai equations. This solvent-free approach offers benefits in dispersion of clay for industrial applications of rubber nanocomposites.

Correlation between (nano)-mechanical and chemical changes occurring during photo-oxidation of filled vulcanised styrene butadiene rubber (SBR)

Photo-oxidation at λ > 290 nm was performed on vulcanised styrene butadiene rubber (SBR) designed for flooring applications. The effect of the presence of coated titanium dioxide (TiO2), used as a pigment, was evaluated. The chemical and nano-mechanical changes occurring at the surface during irradiation were studied by micro-FTIR spectroscopy and atomic force microscopy (AFM). Both techniques were used to obtain the oxidation profiles in the depth of the composites (in the absence and presence of TiO2) to characterise the oxidative layer formation. The nano-mechanical and chemical profiles were superimposed for both composites (SBR and SBR/TiO2) suggesting a correlation between both properties. Indeed, the increase of the DMT modulus determined by AFM reflects the crosslinking reactions which occur simultaneously with the formation of oxidised photo-products.Moreover, during irradiation, the mechanical properties were followed at low and high degree of deformation by means of dynamic mechanical analysis (DMA) and tensile test until break, respectively. We demonstrate that the physico-chemical properties of the oxidised layer which represents 20 μm of the 600 μm of the material can explain the loss of mechanical properties for both composites based on vulcanised SBR and SBR/TiO2 during irradiation at λ > 290 nm. We also demonstrate a different mechanical behaviour in presence of TiO2 compared to neat SBR that could be due to a competition between formation of photo-products and the filler-rubber debonding during photo-oxidation.

Synthesis and characterization of styrene butadiene rubber—Bentonite clay nanocomposites

AbstractIn the present study, naturally occurring unfractionated bentonite clay was used to prepare styrene butadiene rubber/bentonite clay nanocomposite by latex stage blending. The bentonite clay was organo‐modified by in situ resol formation by the reaction of resorcinol and formaldehyde. The latex clay mixture was co‐coagulated with acid. The resulting clay masterbatch was compounded and evaluated by Fourier Transform Infrared spectroscopy, X‐ray diffraction (XRD), Transmission Electron Microscopy (TEM), Energy Dispersive X‐ray spectroscopy (EDS), Scanning Electron Microscopy, Thermogravimetric analysis, and Differential Scanning Calorimetry. XRD showed that the interplanar distance of the in situ resol‐modified bentonite clay increased from 1.23 to 1.41 nm for the unmodified bentonite. TEM analysis indicated partial exfoliation and/or intercalation. EDS (Si and Al mapping) of the clay revealed the nature of the dispersion in the nanocomposites vis‐à‐vis the conventional styrene‐butadiene rubber (SBR)/bentonite clay composite. Thermogravimetric analysis was used to compare the decomposition trends of the SBR/clay nanocomposites with the SBR/clay composite. The glass transition temperature of SBR/clay nanocomposites increased as compared with that of neat SBR. Substantial improvement in most of the other mechanical properties was also observed in case of the nanocomposites. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers

Influence of Nanogels on Mechanical, Dynamic Mechanical, and Thermal Properties of Elastomers

Use of sulfur crosslinked nanogels to improve various properties of virgin elastomers was investigated for the first time. Natural rubber (NR) and styrene butadiene rubber (SBR) nanogels were prepared by prevulcanization of the respective rubber lattices. These nanogels were characterized by dynamic light scattering, atomic force microscopy (AFM), solvent swelling, mechanical, and dynamic mechanical property measurements. Intermixing of gel and matrix at various ratios was carried out. Addition of NR gels greatly improved the green strength of SBR, whereas presence of SBR nanogels induced greater thermal stability in NR. For example, addition of 16 phr of NR gel increased the maximum tensile stress value of neat SBR by more than 48%. Noticeable increase in glass transition temperature of the gel filled systems was also observed. Morphology of these gel filled elastomers was studied by a combination of energy dispersive X-ray mapping, transmission electron microscopy, and AFM techniques. Particulate filler composite reinforcement models were used to understand the reinforcement mechanism of these nanogels.

Rheological behavior of gel‐filled raw natural rubber and styrene‐butadiene rubber with reference to gel‐matrix intermixing

AbstractNatural rubber (NR) and styrene‐butadiene rubber (SBR) latex gels were prepared by sulfur prevulcanization technique with varying amounts of curing agent and accelerator systems to generate gradient in crosslink density. These gels were characterized by solvent swelling, dynamic light scattering, atomic force microscopy, and mechanical properties. Crosslinked NR gels were intermixed with neat SBR matrix and vice versa. Rheological behavior of chemically crosslinked gel‐filled NR and SBR was studied by capillary rheometry. Intermixing of crosslinked gels in the rubber matrices resulted in a considerable reduction in apparent shear viscosity and die swell values. This behavior was found to be dependent on several factors like gel concentration in the matrix, crosslink density of the gels, their size, and distribution. The effect of temperature on viscosity was studied extensively following the Arrhenious‐Eyring model. A shear rate‐temperature superposition mastercurve was constructed to predict the melt viscosities of the systems as a function of temperature. The change in die swell values was related to the change in first normal stress difference. The scanning electron photomicrographs of the extrudates revealed that presence of gels markedly improved the surface roughness of the raw rubbers. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers

Preparation and properties of powder styrene–butadiene rubber composites filled with carbon black and carbon nanotubes

Carbon nanotubes (CNTs) and carbon black (CB) filled powder styrene–butadiene rubber (SBR) composites were prepared by spray drying of the suspension of CNTs and CB in SBR latex. The powders were sphere like and fine with uniform diameters of 10–15 μm. Experimental results showed that the introduction of CNTs into the matrix was beneficial to improve the security of the vulcanization of the rubber composites, and the dynamic and basic mechanical properties of the CNTs/SBR composites were better than those of CB/SBR and neat SBR composites. Observations on the microstructure of the composites indicated that CNTs were well dispersed in the matrix. Morphology of the fracture confirmed that the bonding between CNTs and rubber matrix was strong and load can be transferred to CNTs efficiently during the mechanical property tests. Moreover, the powder SBR composites containing well-dispersed CNTs could be perfect candidate as additives for other polymers.