Showing papers on "Styrene-butadiene published in 2016"

The filler–rubber interface and reinforcement in styrene butadiene rubber composites with graphene/silica hybrids: A quantitative correlation with the constrained region

Abstract: Silica/reduced graphene oxide (SiO 2 @rGO) hybrids were fabricated by an electrostatic assembly, and subsequently, SiO 2 @rGO was incorporated into styrene butadiene rubber (SBR) to fabricate SBR composites. The dispersion status of SiO 2 @rGO and the filler–rubber interfacial interaction were investigated. Likewise, the amount of constrained region was quantified and the findings suggested that the greater the volume fraction of constrained region has possessed, the stronger the interfacial interaction has had. Moreover, the contribution of constrained region to the performance of composites was quantitatively analyzed by the mechanical analysis and the tube model, and the results showed that it is the effect of constrained region, rather than the contents of SiO 2 @rGO, which controls the reinforcement of composites. Specifically, the higher the volume fraction of constrained region is, the better the mechanical properties of composites will be. Also, SiO 2 @rGO can be utilized as novel reinforcing filler for fabricating the green tire materials with high performance.

Design of “Zn2+ Salt-Bondings” Cross-Linked Carboxylated Styrene Butadiene Rubber with Reprocessing and Recycling Ability via Rearrangements of Ionic Cross-Linkings

Abstract: Constructing a reversible supramolecular network cross-linked by noncovalent bonds is an effective approach to realize self-healing as well as reprocessing and recycling for rubbers. Unfortunately, in most case the resultant noncovalent cross-linked rubbers cannot hold enough forces to meet the routine applications. In this paper, our strategy was based on a simple reaction between carboxy groups in carboxylated styrene butadiene rubber (XSBR) and zinc oxide (ZnO), where the formed Zn2+ salt bondings connect separate XSBR molecules. The further self-aggregation of ion pairs of Zn2+ salts resulted in an ionic cross-linked network, whose rearrangements brought XSBR excellent reprocessing/recycling ability. Additionally, the reclaimed XSBR exhibited valuable mechanical properties due to the compensation of additional formed new Zn2+ salt bondings during recycling. The fresh XSBR with 5 wt % zinc oxide showed a tensile strength of 6.7 MPa, and it was further increased to 10.3 MPa after 3 recycles, which was f...

A new approach to construct three dimensional segregated graphene structures in rubber composites for enhanced conductive, mechanical and barrier properties

Abstract: Styrene butadiene rubber/graphene (SBR3GE-DH) composites with a segregated graphene network, synchronously having high electrical conductivity, mechanical strength and gas barrier properties, were fabricated for the first time using a pre-construction strategy combined with static hot pressing. A “three dimensional graphene (3D-GE) network” with percolation conductive paths was efficiently constructed with an extremely low percolation threshold of 0.55 vol%. Remarkably, a conductivity of 0.033 S m−1 at a 3D-GE content of 1.66 vol% was 8 orders of magnitude higher than that of the sheet-like GE-based composites (SBRGE) prepared by conventional latex compounding. All those outstanding properties were attributable to the well-constructed “3D-GE segregated networks” in the SBR matrix and the strong interfacial adhesion between 3D-GE and the SBR matrix resulting from the geometric confinement of 3D-GE networks. Such performances make SBR3GE-DH composites very competitive for potential applications in high conductive sealing gaskets in the aerospace industry, sealed packages, and gas transport and storage devices.

Enhanced mechanical properties and thermal conductivity of styrene–butadiene rubber reinforced with polyvinylpyrrolidone-modified graphene oxide

Abstract: A facile non-covalent surface treatment method is reported in this paper to modify graphene oxide (GO) sheets with the assistance of polyvinylpyrrolidone (PVP). The PVP-modified GO (PGO) was further adopted to fabricate PGO/styrene–butadiene rubber (SBR) nano-composites through the latex compounding method. The properties of PGO were carefully investigated and interaction between GO and PVP molecules was confirmed. The mechanical properties, dynamic mechanical properties, thermal stability, thermal conductivity as well as swelling properties of the PGO/SBR nano-composites were thoroughly studied. It was confirmed that PVP molecules could have strong interaction with GO via hydrogen bond; thus, the PGO significantly improved the strength of SBR matrix, e.g., 517 and 387 % increase in tensile strength and tear strength, respectively, with the presence of only 5 phr (parts per hundred rubber) PGO in the nano-composite. The presence of PGO had also greatly reduced the glass transition temperature (T g) and enhanced the storage modulus of SBR matrix in the nano-composites. Meanwhile, the maximum heat decomposition temperature (T max) was increased by 23.6 °C; equilibrium solvent uptake in toluene was reduced by 41 % and thermal conductivity was increased by 30 %. All the observations indicated that PVP modification of GO can achieve excellent exfoliation and dispersion of GO in the SBR matrix. These findings were further supported by X-ray diffraction and scanning electron microscopy measurements.

Developing highly conducting and mechanically durable styrene butadiene rubber composites with tailored microstructural properties by a green approach using ionic liquid modified MWCNTs

Abstract: We report the effect of surface modification of multi-walled carbon nanotubes (MWCNTs) by an ionic liquid, 1-ethyl-2,3-dimethylimidazolium bis(trifluoromethylsulfonyl). An apparent physical (cation–π/π–π) interaction between the ionic liquid and MWCNTs was revealed by Raman and UV-visible spectroscopies. The composite loaded with 10 phr MWCNTs exhibits impressive enhancements in tensile strength (381% increase), hardness (34% increase), and abrasion resistance. High electrical conductivity was also achieved at MWCNT loading levels beyond 3 phr loading, with a low percolation threshold (0.023 vol%) for the composites. The microstructural development of conductive networks and uniform dispersion of MWCNTs in the presence of ionic liquid were analysed by TEM and AFM. The experimentally observed mechanical and electrical properties have been compared with theoretical predictions, and confirm that the dramatic improvement in mechanics and electrical conductivity is the outcome of the extremely fine dispersion, the strong secondary network of MWCNTs and improved interaction at the interface via thermodynamically-induced adsorption and physical interlocking of polymer chains in the nanoscopic MWCNT structure. This study demonstrates a simplified and eco-friendly approach to develop multifunctional advanced materials based on ionic liquid modified MWCNT elastomer composites with a much better balance among mechanical properties, conductivity and filler content.

Birchwood biochar as partial carbon black replacement in styrene–butadiene rubber composites:

Abstract: Birchwood feedstock was used to make slow pyrolysis biochar that contained 89% carbon and <2% ash. This biochar was blended with carbon black (CB) as filler for styrene–butadiene rubber (SBR). Comp...

Comparative role of Interface in reinforcing mechanisms of Nano silica modified by Silanes and liquid rubber in SBR composites

Abstract: The objective of the present study is to discuss the role of silica-rubber interfacial interactions on vulcanization kinetics, morphology, mechanical and viscoelastic behavior of silica filled styrene butadiene rubber (SBR) composites. Three types of modifiers, namely mono- and bi-functional silanes as well as hydroxyl-terminated poly butadiene (HTPB) liquid rubber were grafted to silica surface, and composites prepared by these fillers were characterized. Results showed that modified silica, especially grafted by bi-functional silane and liquid rubber, accelerated vulcanization reactions, while pristine silica slowed down vulcanization kinetics of SBR. Morphological studies indicated that all modifications improved dispersion of silica, but HTPB-grafted silica was dispersed to a greater extent in SBR. The observed differences in mechanical and dynamic-mechanical properties of vulcanizates were correlated to the significant differences in silica-rubber and silica-silica interactions. Type of interfacial interactions, i.e. rigid covalent bonds in the bi-functional silane, flexible polymeric bonds in the liquid rubber, and weak energetic bonds in the mono-functional silane, could explain the observed differences. Although all modifications reduced filler networking, rigid covalent bonding by bi-functional silane significantly improved mechanical properties and stabilized the filler network. The mono-functional silane lacks these mechanisms. The soft and flexible interphase of HTPB could create bonds and transfer stresses between the rubber matrix and silica to some extent, however it could not improve the mechanical properties and reduce the Payne effect as much as the bi-functional silane did.

Modification of membrane formulation for stabilization of emulsion liquid membrane for extraction of phenol from aqueous solutions

Abstract: In this study, the removal of phenol from aqueous solutions by a stabilized emulsion liquid membrane (ELM) has been investigated. The emulsion formulation was modified by the addition of a rubbery polymer (Styrene Butadiene Rubber, SBR) and then the resultant emulsion was dispersed in the external phase. The effect of various parameters such as pH of the external phase, internal phase reagent concentration, phase ratio, temperature and intensity of dispersion was studied. A stable emulsion liquid membrane system was obtained by the addition of 3 wt.% of SBR to the membrane phase at 30 °C with an agitation speed of 210 rpm. The addition of SBR to the membrane phase increased the stability of the emulsion liquid membrane from 5 to 35 min, which is ideal for ELM operations. In general, the results showed that by increasing the volume ratio of emulsion phase to feed phase (R ew ), internal phase reagent concentration and decreasing feed pH, the extraction efficiency increases. The best extraction efficiency was obtained at the internal phase reagent concentration of 5000 mg/L, pH F = 1.0, R ew = 0.2, agitation speed of 210 rpm, initial phenol concentration of 100 mg/L and at 30 °C while the emulsion was contained at 3 wt.% of the SBR polymer. In this condition, the maximum extraction efficiency of 90.1% was obtained within less than 35 min.

Synergistic Effect of Clay Platelets and Carbon Nanotubes in Styrene–Butadiene Rubber Nanocomposites

Abstract: Nanoscale materials have provided a big advantage for enhancing the performance of rubber composites through leading the synergy effects in the physical and chemical properties. Here, the authors prepare hybrid fillers using a simple solution-based method, based on electrostatic interactive assembly, of hydroxyl-functionalized exfoliated montmorillonite (FE-MMT) and cetyl trimethylammonium bromide-modified multiwall nanotube (MWNT). The driving force of hybridization is due to specific interaction between the positive charge on the MWNT and the negative charge of hydroxyl group on MMT. To improve their dispersion, the obtained hybrid fillers are then co-coagulated with styrene–butadiene rubber (SBR) latex to prepare elastomeric composites. Homogenous dispersion of the hybrid nanofillers in the SBR matrix results in a remarkable improvement in mechanical properties such as modulus (0.31 MPa) and tensile strength (75 MPa) at low loadings. Moreover, the prepared composite of hybrid nanofillers and rubber in the SBR matrix exhibits outstanding thermal (0.3779 W m−1 K−1) and electrical conductivities (15 kΩ) and gas barrier performance (9.16 × 10−45 m4 s−1 N−1). The synergistic reinforcement of SBR achieved by the combined incorporation of MWNT and MMT makes it ideal for use in conscious tires. This research opens up a wealth of new opportunities to prepare high performance rubber composites for future engineering applications.

Mechanical properties and thermal aging behaviour of polyisoprene/polybutadiene/styrene-butadiene rubber ternary blend reinforced with carbon black

Abstract: The goal of this work was to study thermal aging of sulfur cured ternary blends based on polyisoprene (NR), polybutadiene (BR) and styrene butadiene rubber (SBR) (NR/BR/SBR = (25/25/50) reinforced with different loading carbon black (CB) nanoparticles (0–100 phr). The specimens were subjected to thermo-oxidative aging at 100 °C, for two times: at 72 h and 168 h, respectively, and then mechanically stretched to fracture by tension with a Zwick 1425 universal tensile testing machine. Rheological and mechanical properties were used as characterization of the ternary rubber blends. The reinforcing performance of the filler was investigated using rheometric, mechanical and swelling measurements, thermogravimetric analysis (TGA), scanning electron microscopy (SEM) and Fourier Transform Infrared Spectroscopy with Attenuated Total Reflectance (FTIR-ATR). Tensile and swelling properties were determined before and after thermal aging. The rheological properties optimum cure time (t c90 ), scorch time (t s2 ) and the cure rate index (CRI) are decrease in NR/BR/SBR/CB = (25/25/50) ternary rubber blend with 60 phr of filler loading. The movement absorption band from 1451 cm −1 –1455 cm −1 the interaction between rubber blend and CB filler is confirmed.

Surface modification of novel rice bran carbon functionalized with (3-Mercaptopropyl) trimethoxysilane and its influence on the properties of styrene-butadiene rubber composites

Abstract: In the present study, surface modification of novel environment-friendly Rice Bran Carbon was carried out by mixed acid treatment followed by reaction with multifunctional silane, (3-Mercaptopropyl...

The Synergy of Double Cross-linking Agents on the Properties of Styrene Butadiene Rubber Foams.

Abstract: Sulfur (S) cross-linking styrene butadiene rubber (SBR) foams show high shrinkage due to the cure reversion, leading to reduced yield and increased processing cost. In this paper, double cross-linking system by S and dicumyl peroxide (DCP) was used to decrease the shrinkage of SBR foams. Most importantly, the synergy of double cross-linking agents was reported for the first time to our knowledge. The cell size and its distribution of SBR foams were investigated by FESEM images, which show the effect of DCP content on the cell structure of the SBR foams. The relationships between shrinkage and crystalline of SBR foams were analyzed by the synergy of double cross-linking agents, which were demonstrated by FTIR, Raman spectra, XRD, DSC and TGA. When the DCP content was 0.6 phr, the SBR foams exhibit excellent physical and mechanical properties such as low density (0.223 g/cm3), reduced shrinkage (2.25%) and compression set (10.96%), as well as elevated elongation at break (1.78 × 103%) and tear strength (54.63 N/mm). The results show that these properties are related to the double cross-linking system of SBR foams. Moreover, the double cross-linking SBR foams present high electromagnetic interference (EMI) shielding properties compared with the S cross-linking SBR foams.

Effects of silanization temperature and silica type on properties of silica-filled solution styrene butadiene rubber (SSBR) for passenger car tire tread compounds

Abstract: Influence of silanization temperature on properties of silica-filled solution polymerized styrene butadiene rubber was investigated. Two types of silica, i.e., highly dispersible silica (HDSi) and conventional silica (CSi), were compared. Results show that the increased silanization temperature leads to the enhanced rubber–filler interaction, filler dispersion, and cross-link density giving rise to the improvement in vulcanizate properties such as modulus, heat build-up (HBU), and dynamic set, as well as tire performance, e.g., wet grip (WG), rolling resistance (RR), and abrasion resistance. Great care, however, must be taken to avoid the scorching phenomenon during the mixing process at too high temperature. Taken as a whole, the balanced properties are found at the silanization temperature of 140°C. Surprisingly, HDSi provides insignificant differences in degree of filler dispersion, WG, and RR, compared to CSi, despite its claimed greater dispersability. Probably, the relatively long mixing time used in this experiment may override the influence of silica type. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43342.

High-temperature functional analysis of bitumen modified with composite of nano-SiO2 and styrene butadiene styrene polymer

Abstract: Most parts of Iran have completely different climates in different seasons of year. In other words, in summer it is very warm and in winter it becomes very cold. Achieving modified bitumen that could function adequately in both high and low temperature has always been under attention of researchers. One of bitumen modifiers is styrene butadiene styrene polymer. Because bitumen modified by styrene butadiene styrene does not show expected field function in both high and low temperatures, largely due to phase separation of bitumen and polymer, in the present study it has been tried to analyze the low-temperature function of bitumen modified by combining nano-SiO2 and styrene butadiene styrene polymer. The study reveals that adding nano-SiO2 by 3% and 4% of bitumen weight to the double combination of bitumen and styrene butadiene styrene polymer has improved its function in low temperature. This study has innovation as it deals with the analysis of low temperature function of nano-SiO2 and SBS in modi...

Rheological properties of styrene butadiene rubber modified bitumen binder

Abstract: The study investigates the rheological properties of bitumen of 60-70 penetration grade modified with Styrene Butadiene Rubber (SBR). SBR is an elastomer which is an important sort of synthetic rubber. It is a copolymer whose molecular structure primarily consists of organic compound styrene and butadiene chain. Bitumen is visco-elastic in nature. The rate of load application and temperature has a great influence on its performance. Various fundamental properties of bitumen were evaluated, namely complex shear modulus (G*), short-term ageing, long-term ageing, viscosity, penetration and softening point by using Dynamic Shear Rheometer (DSR), Rolling Thin Film Oven Test (RTFOT), Pressure Aging Vessel (PAV), Rotational Viscometer (RV), Penetrometer and Ring and Ball Test, respectively. The binders were mixed with varying percentage of SBR i.e. 0, 1, 2, 3, 4, and 5% by the weight of bitumen binder. The use of SBR has played an active role in improving the viscoelastic properties of bitumen. The use of SBR modifier changes the rheological behavior of bitumen by increasing its complex shear modulus (G*) and the resistance of mixture against permanent deformation (rutting). It was also found that increasing the content of SBR led to the increase in viscosity of modified bitumen, which helps in elevating the mixing and compaction temperature of asphalt mixtures.