Modified and unmodified multiwalled carbon nanotubes in high performance solution-styrene-butadiene and butadiene rubber blends

The outstanding properties of carbon nanotubes have generated scientific and technical interests in the development of nanotube-reinforced polymer composites. Therefore, we investigated a novel mixing approach for achieving a good dispersion of multiwalled carbon nanotubes (CNTs) in a rubber blend. In this approach the CNTs were incorporated into a 50:50 blend of solution-styrene-butadiene rubber and butadiene rubber. First, the CNTs were predispersed in ethanol and then this CNT-alcohol suspension was mixed with the rubber blend at elevated temperature. The rubber nanocomposites prepared by such method exhibit significantly enhanced physical properties already at very low nanotube concentrations. Additionally, we have analysed the dielectric and thermal properties of the compound. The high aspect ratio of the carbon nanotubes enabled the formation of a conductive percolating network in these composites at concentrations below 2 wt.%. In contrast to the electrical conduction behaviour, the thermal conductivity of the composites has not been influenced significantly by the presence of carbon nanotubes. Dynamic mechanical analysis indicates that the incorporation of CNTs affects the glass transition behaviour by reducing the height of the tan δ peak considerably. Above the glass transition temperature the storage modulus has been increased after incorporation of a small amount of CNTs. Finally, the ‘Payne effect’, an indication of filler-filler interactions, was observed at very low concentrations of CNT in the rubber matrix.     

Elucidating the interactions between carbon nanotubes and carbon black with styrene butadiene rubber

The reinforcement mechanism of carbon nanotubes (CNT) on styrene butadiene rubber is studied through dynamic and swelling tests. Compounds containing carbon black (CB) and an unfilled one were prepared for comparison purposes. The dynamic properties are interpreted through the Maier-Göritz model to distinguish the contributions of stable and unstable crosslinks to the storage modulus, finding that the unstable ones become more relevant in samples containing a CNT concentration higher than 5 phr. In addition, the crosslinks density estimated by swelling and the stable contribution obtained with dynamical properties present the same tendency with the CNT amount. The former presents lower values, which can be explained considering that only stable crosslinks remain in the equilibrium-swollen state, while in the second one both stable and unstable are considered. In addition, differences in the filler-polymer interaction mechanisms are observed according to the morphology and aspect ratio of CNT in contrast to CB.     

High-performance sodium polyacrylate nanocomposites developed by using ionic liquid covalently modified multiwalled carbon nanotubes

Ionic liquids grafted with multiwalled-nanotubes (CNT Br/NTf₂), involving hydrophilic bromide salt and hydrophobic bis(trifluoromethanesulphonyl)imide salt, were prepared by amidation, followed by an easy solution-casting method of blending CNT Br/NTf₂ with sodium polyacrylate (PAA) as well as crosslinking agent (XR-100) to form PAA hybrid nanocomposites. The uniform dispersion of CNT Br/NTf₂ were analyzed by TEM. The defects and physical properties of fillers were characterized by Raman spectroscopy, Contact angle test, and TGA. Furthermore, microstructures of hybrid nanocomposites were characterized by SEM, from which it can be found that fillers were homogeneously distributed in the PAA matrix. CNT Br/NTf₂ significantly improved the mechanical properties and tensile fatigue resistance, as well as offered tunable swelling behavior of PAA nanocomposites without wasting too much of thermal stability. This study offers a simple approach to develop multifunctional materials based on ionic liquids covalently modified MWCNTs PAA nanocomposites.     

Preparation and characterization of carboxylated styrene butadiene rubber (XSBR)/multiwall carbon nanotubes (MWCNTs) nanocomposites

This study deals with the preparation of carboxylated styrene butadiene rubber (XSBR)/multiwall carbon nanotubes (MWCNTs) nanocomposites prepared in the latex form by means of a ball mill. Two types of CNTs, i.e., non-functionalized and OH-functionalized (CNT?COH) were used. The rheological properties, FTIR spectrums, SEM micrographs and stress relaxation experiments were exploited to evaluate the resulting nanocomposites. For a given frequency, both the viscosity and storage modulus increased as the concentration of CNT was augmented with the greatest value for the nanocomposites loaded with CNT?COH. The viscosity of nanocomposites exhibited a shear thinning behavior throughout applied frequency and indicated a power law index of about n?=?0.22. Nanocomposite ATR analyses revealed the presence of physical interaction of H-bonding type between hydroxyl group of CNT?COH and carboxyl group of XSBR for XSBR?CCNTOH nanocomposites. A mechanism based on the chemistry of medium was proposed to explain the development of H-bonding. SEM micrographs confirmed the uniformity of carbon nanotubes dispersion in the resulting microstructure. A two-step innovative stress relaxation experiment was performed on the prepared nanocomposites through which the resulting microstructure of nanocomposites was further explored. The relaxation behavior of nanocomposites (both in first and second steps) were modeled and well predicted using Prony series and the parameters of generalized Maxwell equation for stress relaxation, $ \tau_{i} $ and $ g_{i} $ were computed, as well.     

Synergistic effect of carbon nanofiber decorated with iron oxide in enhancing properties of styrene butadiene rubber nanocomposites

Elastomer nanocomposites reinforced with carbon nanofiber (CNF) decorated with metal nanoparticles exhibit excellent thermal, mechanical, and magnetic properties with low volume fraction of the reinforcement. Generally, metal nanoparticles are used to modify the surface of CNF, to improve their dispersion and contact resistance in the polymer matrix. In this study, Fe₂O₃ metal nanoparticles were decorated on CNF by electrostatic attraction via a green and facile solution‐based method. Interestingly, the CNF decorated with Fe₂O₃ (CNF‐Fe₂O₃)/elastomer improved both the tensile strength and the fatigue property of plain CNF/elastomer by as much as 57.2% and 27.2%, respectively. Moreover, the CNF‐Fe₂O₃/elastomer exhibited superior thermal conductivity, a twofold enhancement compared with carbon fibers. The elastomer nanocomposites consisting of CNF‐Fe₂O₃ also exhibited enhanced magnetic properties due to synergies between the Fe₂O₃ nanoparticles and the CNF. The elastomer nanocomposites prepared with CNF‐Fe₂O₃ will open significant new opportunities for preparing advanced elastomer nanocomposites for future engineering applications. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45376.     

固相法改性淀粉／炭黑／丁苯橡胶复合材料的制备与性能研究

采用固相法制备了淀粉接枝马来酸酐（MAH）和丙烯酸丁酯（BA）的共聚物Starch-gMAH／BA（SMB）。采用机械共混法用15phr的改性淀粉（SMB）代替等量的炭黑（CB）,制备了改性淀粉／炭黑／丁苯橡胶复合材料（SMt3／CB／SBR）,研究了复合材料的力学性能、热氧老化性能、动态力学性能以及微观形态。结果表明,SMB／CB／SBR复合材料的力学性能优于未改性淀粉／CB／SBR复合材料,拉伸强度及扯断伸长率等性能优于SBR／CB复合材料;且SMB／CB／SBR复合材料具有更好的耐热氧老化性能;与SBR／CB复合材料相比,SMB／CB／SBR复合材料具有更低的滚动阻力;微观形态显示,淀粉经改性后粒子尺寸减小,在SBR基体中的分散性得到改善,与SBR基体的相容性得到提高。     

Preparation and characterization of exfoliated graphite and its styrene butadiene rubber nanocomposites

Nanocomposites consisting of styrene butadiene rubber (SBR) reinforced with the modified-graphite and natural-graphite with concentrations of 5 wt% were fabricated. Processing techniques such as acid treatment, thermal shock, sonication were employed in the fabrication of modified-graphite.The graphite platelets oxidized using sulfuric and nitric acids were analyzed by the Raman scattering, Fourier transformed infrared spectroscopy (FT-IR) and X-ray diffraction (XRD). The FT-IR results indicate the presence of acid groups in the treated samples, and Raman spectroscopy of acid-graphite platelets further corroborate the formation of surface defect due to the introduction of functional groups. However, the structure of XRD peaks did not change irrespective of processing techniques.The SBR-based nanocomposites were characterized using the scanning electron microscopy (SEM), rheometer, Instron tensile machine, thermal and electrical analyser.The results showed that nanocomposites onto acid-graphite platelets enhanced mechanical properties and fatigue properties of nanocomposites compared to those containing natural-graphite due to the increase in the interaction between the polymer and the modified-graphite. And the dynamic properties of nanocomposites had no influence according to the processing techniques. Also, thermal and electrical properties of nanocomposites using acid-graphite platelets were enhanced due to the broadened specific surface by the acid treatment.     

Rheological behavior of nanocomposites of natural rubber and carboxylated styrene butadiene rubber latices and their blends

Flow behavior of latices is industrially important for the manufacturing of various latex goods. Rheology of latices having fillers can assist in the understanding and quantification of the matrix–filler interaction. The impact of layered silicates such as sodium bentonite and sodium fluorohectorite on the rheological behavior of natural rubber, carboxylated styrene butadiene rubber latices, and their blends was analyzed with special reference to shear rate, temperature, and filler loading. The layered silicates‐reinforced latex samples were characterized by X‐ray diffraction technique to analyze the extent of intercalation and exfoliation. In the presence of layered silicates, latex systems exhibited enhancement in viscosity due to the network formation. Because of the breaking of networks at higher temperature, the viscosity of all systems decreased with increase in temperature. Layered silicates‐reinforced latex systems showed pseudoplastic flow behavior and possesses enhanced zero shear viscosity and yield stress. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 2355–2362, 2006     

Physicomechanical properties of wollastonite (CaSiO3)/styrene butadiene rubber (SBR) nanocomposites

The purpose of this study was to investigate the effect of bare wollastonite (BW) and modified wollastonite (MW) nano‐rods into the styrene butadiene rubber (SBR). SBR nanocomposites were prepared by the incorporation of different wt % (0.3–4.5) of BW and MW nanorods. All nanocomposites were characterized by thermal gravimetric analyzer (TGA) and differential scanning calorimeter (DSC). The particle size and morphology of BW and MW nanorods were characterized by field‐emission scanning electron microscope (FE‐SEM), transmission electron microscope (TEM), and Fourier transform infrared (FTIR) spectrophotometer, while FE‐SEM and AFM analyses were performed for BW/SBR and MW/SBR nanocomposites. The obtained results revealed the existence of stronger interaction between the SBR and MW nanorods into MW/SBR as compared to BW/SBR nanocomposites. FE‐SEM and AFM images showed a perfect dispersion of the MW nanorods in SBR matrix at 3 wt % loading. Thermal stability of MW/SBR nanocomposites was also increased significantly by the addition of MW nanorods. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42811.     

Direct electrochemistry of guanosine on multi-walled carbon nanotubes modified carbon ionic liquid electrode

A multi-walled carbon nanotubes (MWCNTs) modified carbon ionic liquid electrode (CILE) was fabricated and used to investigate the electrochemical behavior of guanosine. CILE was prepared by mixing hydrophilic ionic liquid 1-ethyl-3-methylimidazolium tetrafluoroborate (EMIMBF₄), graphite powder and liquid paraffin together. The fabricated MWCNTs/CILE showed great electrocatalytic ability to the oxidation of guanosine and an irreversible oxidation peak appeared at 1.067 V (vs. SCE) with improved peak current. The electrochemical behavior of guanosine on the MWCNTs/CILE was carefully studied by cyclic voltammetry and the electrochemical parameters such as the charge transfer coefficient (α) and the electrode reaction standard rate constant (k_s) were calculated with the result as 0.66 and 2.94 × 10⁻⁴ s⁻¹, respectively. By using differential pulse voltammetry (DPV) as the detection method, a linear relationship was obtained between the oxidation peak current and the guanosine concentration in the range from 1.0 × 10⁻⁷ to 4.0 × 10⁻⁵ mol/L with the detection limit as 7.8 × 10⁻⁸ mol/L (3σ). The common coexisting substances showed no interferences to the guanosine detection and the modified electrode showed good ability to distinguish the electrochemical response of guanosine and adenosine.     

Effect of carbon nanotubes with different lengths on mechanical and electrical properties of silica-filled styrene butadiene rubber compounds

Carbon nanotubes (CNTs) having three different lengths of 5, 30, and 100 μm were added to silica-filled styrene butadiene rubber (SBR) compounds in order to investigate the effect of the CNT addition on the dynamic and electrical properties. The amounts of CNTs were 1, 2, 4, and 7 phr, while the amount of silica was set high at 80 phr to clearly demonstrate the performance of the CNTs as fillers. The effect of CNTs on the silica-filled SBR compounds on the tensile properties is not significant, but the addition of longer CNTs with high loading severely deteriorated the dynamic properties, but considerably enhanced electrical conductivity. The medium loading of CNTs in silica-filled SBR compounds is suitable for the improvement of the electrical conductivity without severely sacrificing the dynamic properties.     

离子液体改性石墨烯在橡胶中的应用进展

综述了离子液体改性石墨烯的改性方法,及离子液体改性石墨烯在改善橡胶力学性能、热稳定性、导电性能、导热性能及气体阻隔性能等方面的应用现状及进展.     

接枝改性淀粉/丁苯橡胶复合材料的制备与性能研究

采用固相法制备了玉米淀粉接枝马来酸酐(MAH)、甲基丙烯酸甲酯(MMA)和丙烯酸丁酯(BA)的共聚物Starch-g-MAH/MMA/BA(SMMB)。采用机械共混法制备了接枝改性淀粉/丁苯橡胶(SMMB/SBR)复合材料,研究了复合材料的力学性能、动态力学性能以及微观形态。结果表明,SMMB/SBR复合材料的力学性能优于未改性淀粉/SBR复合材料和纯SBR。与纯SBR硫化胶相比,SMMB/SBR复合材料的玻璃化转变温度(Tg)升高。微观形态分析显示,淀粉经改性后粒子尺寸减小,在SBR中的分散性得到了改善,与SBR基体的相容性得到了提高。     

丁苯橡胶改性沥青的高性能化和稳定化

在丁苯橡胶(SBR)改性沥青时加入稳定剂，运用反应共混方法研制出了高性能、高温贮存稳定的SBR改性沥青。利用动态力学性能分析和相形态观察分别比较了加入稳定剂对SBR改性沥青的动态力学性能和体系相形态在高温下的影响。结果表明，与未加稳定剂时相比，加入稳定剂的SBR改性沥青除能保持良好的低温性能之外，其高温物理机械性能有了明显的改善，且在高温下贮存数天后仍稳定。稳定剂的加入使得改性沥青体系内形成了弹性交联网络结构，显著改善了SBR改性沥青的高温贮存稳定性能和高温物理机械性能。     

Wear characteristics of styrene butadiene rubber/natural rubber blends with varying carbon blacks by DIN abrader and mining rock surfaces

In this study, nine rubber compounds were produced by varying the proportions of natural rubber (NR), styrene butadiene rubber (SBR), and four different carbon blacks. Tensile and tear properties are enhanced by the addition of intermediate super abrasion furnace (ISAF) N231, and modulus increases for the compounds containing N234 carbon blacks. The wear behavior of the prepared rubber vulcanizates against various rocks, such as, granite, shale, schist, sandstone, coal, and concrete, at 4.4 N normal load and 0.8 m/s relative sliding speed were studied in a specially fabricated experimental setup. The DIN abrasion testing results show good abrasion resistant properties of 70 phr NR and 30 phr SBR with N231 grade ISAF type carbon black. Also, moderate abrasion resistance is found in rubber compound containing 80 phr NR and 20 phr SBR with N234 grade ISAF type of carbon black. Out of the various rock types, the schist and sandstone are observed to be highly abrasive against the prepared rubber compounds. The microscopic examination of the abraded rubber surfaces has indicated the formation of longitudinal grooves against harder rocks and transverse ridges against softer rocks. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

The effect of partial replacement of carbon black by carbon nanotubes on the properties of natural rubber/butadiene rubber compound

The basic objective of this study is to investigate the mechanical properties of tyre tread compounds by gradual replacement of carbon black by multiwalled carbon nanotubes (MWCNTs) in a natural rubber–butadiene rubber‐based system. A rapid change in the mechanical properties is noticed even at very low concentrations of nanotubes though the total concentration of the filler is kept constant at 25 phr (parts per hundred rubber). The correlation of the bound rubber content with MWCNT loading directly supports the conclusion that MWCNTs increase the occluded rubber fraction. Transmission electron microscopy reveals a good dispersion of the MWCNT up to a certain concentration. In the presence of MWCNT, a prominent negative shift of the glass transition temperature of the compound is found. Thermal degradation behavior, aging, and swelling experiments were also carried out to understand the resulting effect of the incorporation of MWCNT in the rubber matrix. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 3153–3160, 2013     

化学改性脱硫灰取代部分炭黑制备环保型丁苯橡胶及其性能

用硅烷偶联剂Si69和KH550对脱硫灰进行化学改性,用改性脱硫灰取代部分炭黑与丁苯橡胶复合,制备环保型丁苯橡胶,对其进行了表征,采用均匀设计结合BP神经网络建立模型优化工艺参数. 结果表明,最优制备工艺参数为Si69和KH550用量分别为4.3wt%和3.8wt%、无水乙醇用量22.1wt%、搅拌速度705 r/min、反应温度82℃,该条件下所制环保型丁苯橡胶的力学性能为拉伸强度19.64 MPa、撕裂强度44.96 kN/m、邵氏A硬度66. 实验结果与模型预测值吻合较好,相对误差为3.03%~2.65%.     

改性碱式氯化镁晶须/丁苯橡胶复合材料制备与性能研究

以工业活性轻烧氧化镁粉和盐酸为原料,采用水溶液法制备了碱式氯化镁晶须,继而采用硅烷偶联剂对碱式氯化镁晶须进行改性,然后将其与丁苯橡胶混炼得到改性碱式氯化镁晶须/丁苯橡胶复合材料,研究了改性碱式氯化镁晶须对丁苯橡胶力学性能及热学性能的影响。结果表明：采用水溶液法制备得到的碱式氯化镁晶须结构为Mg₂（OH）₃Cl·4H₂O,呈微细纤维状,分布较均匀,长径比大于20;改性碱式氯化镁晶须的加入,可以改善丁苯橡胶的机械强度和阻燃性能。     

Synergistic effect of carbon nanotubes and clay platelets in reinforcing properties of silicone rubber nanocomposites

Fine powders of montmorillonite (MMT)/multiwalled carbon nanotube (MWCNT) hybrids have been prepared by simple grinding of MWCNT with MMT in different weight ratios of MMT to MWCNT (10 : 1, 6 : 1, 3 : 1, 1 : 1, and 1 : 3) and characterized by wide‐angle X‐ray diffraction, field emission scanning electron microscopy, and transmission electron microscopy. These studies have established the formation of the exfoliated structures of MMT/MWCNT (1 : 1) hybrid, in which MWCNTs exist in the state of single nanotubes that are adsorbed and intercalated on the surface and in between the MMT nanoplatelets. The hybrid has subsequently been used as reinforcing nanofiller in the development of high‐performance silicone rubber (SR) nanocomposites, and a remarkably synergistic effect of MMT and MWCNT on SR properties has been observed. The tensile strength of SR containing 1% w/w of the MMT/MWCNT (1 : 1) hybrid is improved by 215%, whereas the SR filled with MMT or MWCNT alone showed an improvement of 46 and 25%, respectively, over that of unfilled SR. In addition, SR/1 wt % MMT/MWCNT (1 : 1) nanocomposites also exhibit the maximum improvement in thermal stability corresponding to 10% weight loss by 70°C, crystallization and melting temperatures increased by 8 and 6°C as inferred from thermogravimetric analysis and differential scanning calorimetry, respectively. This approach is promising for the preparation of high‐performance SR nanocomposites by using different dimension nanofillers together. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41818.     

Improvement of cutting and chipping resistance of carbon black-filled styrene butadiene rubber by addition of nanodispersed clay

A novel, effective approach to improve the cutting and chipping resistance (CCR) of carbon black (CB)-filled styrene butadiene rubber (SBR) composite was reported in this study. CCR of SBR was dramatically improved more than 30% by addition of 4 phr nanodispersed clay (NC), while not decreasing the stress at 100% and the Shore A hardness of the composite. The curing characteristics, loss tangent (tan δ), and the strength of filler network of the composites were further measured by a Disk Oscillating Rheometer and a rubber processing analyzer, respectively. It was found that the addition of NC led to a slightly lower crosslink density, higher tan δ, and stronger filler network, which contributed to the higher CCR. Therefore, the novel layered NC is more efficient in improving CCR when compared with CB. The results are expected to promote the application of NC in rubber industry. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012