芳纶纤维增强丁腈橡胶的摩擦性能

研究了芳纶纤维增强丁腈橡胶(NBR)复合材料的物理机械性能和摩擦性能,并用扫描电子显微镜分析了芳纶纤维增强NBR复合材料的磨损表面和磨屑形貌。结果表明,芳纶的加入提高了NBR的拉伸强度;随着芳纶用量的增大,复合材料的扯断伸长率降低;芳纶的加入降低了NBR的摩擦系数和磨损率;当芳纶用量为20份时,复合材料的综合性能最佳。加入芳纶对NBR摩擦磨损形式的改变是NBR摩擦性能提高的重要原因。     

Mechanical and tribological performance of acrylonitrile-butadiene rubber/carbon black/cryptocrystalline graphite composites

In this study, cryptocrystalline graphite (CG) was investigated as a novel functional filler for acrylonitrile-butadiene rubber (NBR)/carbon black (CB) composites. NBR/CB/CG composites are characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) as well as differential scanning calorimetry (DSC). The results showed that NBR/CB/CG-10 increased by 18.2%, 11.0%, and 10.0% in tensile strength, 300% tensile modulus and tear strength, respectively compared with NBR/CB. Uniform filler dispersion and stronger interfacial interaction contributed to enhancing the mechanical property of NBR/CB/CG composites. It was revealed that the small particle size, rough surface, and defective structure of CG facilitated its exfoliation and intercalation. In addition, the tribological performance of NBR/CB/CG composites was tested on a ring-on-block wear tester under dry sliding conditions. The friction coefficient and specific wear rate of NBR/CB/CG-5 reduced by 50.3% and 51.4%, respectively through the formation of fine lubrication and transfer films. CG enhanced the thermal stability, mechanical, and tribological performance of NBR composites simultaneously and the results of this work proved that CG would be a cost-effective and resource-available functional filler especially suitable for rubber seal application.     

Effect of acrylonitrile content of acrylonitrile butadiene rubber on mechanical and thermal properties of dynamically vulcanized poly(lactic acid) blends

We report here the morphology, thermal and tensile properties of poly(lactic acid) (PLA) blends composed of acrylonitrile butadiene rubber (NBR) with different acrylonitrile contents with/without dynamic vulcanization by dicumyl peroxide (DCP). The interfacial tension of PLA and NBR measured by contact angle measurement decreased as the acrylonitrile content of NBR decreased. Likewise, SEM images showed that the rubber particle size reduced with decreasing acrylonitrile content owing to the stronger interfacial adhesion between the PLA matrix and NBR domains. Incorporation of DCP at 1.0 phr for dynamic vulcanization led to higher crosslink density and, in turn, optimal tensile strength and tensile toughness as a result of the action of PLA‐NBR copolymer as a reactive compatibilizer. The dynamic vulcanization of the blends containing low acrylonitrile NBR gave the most improved tensile properties because the free radicals from DCP decomposition preferentially attacked the allylic hydrogen atoms or double bonds of the butadiene backbone. Accordingly, more NBR macroradicals were generated and probably more PLA‐NBR copolymers were produced. Moreover, further addition of DCP at 2.0 phr provided a large amount of crosslinked NBR gel, which significantly degraded the tensile properties. From the DSC results, dynamic vulcanization lowered the cold crystallization temperature, implying an improvement of cold crystallization. Finally, TGA results showed a higher degradation temperature as a function of DCP content, which suggested that thermal stability increased due to stronger interfacial adhesion as well as higher gel content. © 2019 Society of Chemical Industry     

温度对酚醛树脂/丁腈橡胶复合材料摩擦学性能的影响

采用机械共混法将酚醛树脂（PF）与丁腈橡胶（NBR）进行混合而制得PF/NBR复合材料,研究了PF用量对NBR的拉伸性能、撕裂性能及硬度的影响,使用多功能材料表面性能综合测试仪、三维表面形貌仪和扫描电子显微镜对力学性能最优的PF/NBR复合材料试样A 2（添加5份PF）在不同温度下的摩擦性能进行了探究,并与未添加PF的试样A 0进行了对比,此外还对PF/NBR复合材料的磨损机理进行了初步分析。结果表明,当温度超过75 ℃时,试样A 0的摩擦系数曲线整体呈持续上升的趋势,同时其表面有较多孔洞,分子间结合力下降,耐磨性变差,而试样A 2的摩擦系数则基本保持稳定,磨损行为表明其磨损机理由磨粒磨损逐渐转变为黏着磨损;相对于试样A 0而言,试样A 2在高温下仍能保持较好的摩擦性能。     

基于两种丁腈橡胶复合填料的高性能离合器摩擦材料的研究

以丁腈胶乳改性水基酚醛树脂为胶粘剂,分别以玻璃纤维和复合包芯纱纤维为增强材料,采用两种新型丁腈复合填料[含9%硫化丁腈橡胶(NBR)和含20%未硫化NBR]为主要填料制备高性能离合器摩擦材料。实验结果表明,当m(9%硫化NBR)∶m(20%未硫化NBR)=1∶1[即W(NBR)≈16%]时,制取的摩擦材料具有良好的摩擦磨损性能、适中的硬度、良好的冲击强度和较低的噪音。     

填充型NBR/EPDM导电复合材料的研究

研究了石墨/炭黑填充的NBR/EPDM导电复合材料力学性能、动态力学性能和压阻、温阻特性。结果表明,随NBR用量的减少,复合材料拉伸强度、撕裂强度和拉断伸长率均降低;与纯胶相比,填料在NBR/EPDM中分散性变差,复合材料Payne效应和损耗因子都增大。电阻率测试结果表明,NBR/EPDM并用胶电阻率明显低于纯胶;恒温下其电阻率随压力的增大先减小后增大;恒压下其电阻率随温度的升高而减小;NBR/EPDM并用比不同时,复合材料电阻率随压力、温度的变化趋势不尽相同。     

Homogeneous Styrene Butadiene/Acrylonitrile Butadiene Rubber Blends

The graft copolymerization of acrylonitrile (AN) onto butadiene rubber (BR) was carried out in toluene at 80°C, using dibenzoyl-peroxide (BPO) as initiator. The synthesized poly acrylonitrile-grafted-butadiene rubber (AN-g-BR) was characterized by N% elemental analysis and Fourier-transform infrared (FT-IR) spectroscopy. Styrene butadiene rubber/acrylonitrile butadiene rubber (SBR/NBR) blends were prepared with different blend ratios in presence and absence of AN-g-BR, where the homogeneity of such blends were examined with intrinsic viscosity (η) measurements, differential scanning calorimetry (DSC), and scanning electron microscopy (SEM). The scanning electron micrographs illustrate disappearance of the macro-scale phase separation of SBR/NBR rubber blend as a result of the incorporation of AN-g-BR into that blend. Viscosity measurements confirm homogeneity of that blend. Differential Scanning Calorimetry traces exhibit shifts in glass transition temperatures (T _g's) of SBR and NBR in their blend, indicating some degree of homogeneity. Physico-mechanical properties of the rubber blend vulcanizates with different blend ratios, in presence and absence of AN-g-BR, were investigated before and after accelerated thermal aging. The SBR/NBR (25/75) homogeneous blend possessed the best physico-mechanical properties after thermal aging, together with the best swelling behavior in motor oil. The physico-mechanical properties of SBR/NBR (25/75) filled blend with different types of inorganic fillers during thermal aging were studied.     

A comparative study on curing characteristics and thermomechanical properties of elastomeric nanocomposites: The effects of eggshell and calcium carbonate nanofillers

After‐hatching eggshell (AHES) nanobiofiller and nanocalcium carbonate (nano‐CA) were separately added to various elastomers, such as acrylonitrile butadiene rubber (NBR), styrene butadiene rubber (SBR), and natural rubber (NR), in various amounts of 5, 10, and 15 phr. The effect of particle size and dispersion of such nanofillers on thermomechanical properties and curing characteristics were then investigated. The ultimate tensile properties of SBR and NR nanocomposites were improved to some extent when 5 phr of AHES nanofiller was added to the rubber compound compared to CA. In the case of NBR nanocompounds, however, the mechanical properties were seemingly comparable, irrespective of the type of nanofiller. This contradictive behavior could be attributed to the alteration of crosslink density due to particular filler–matrix interaction while using mineral and natural fillers. The results of the rheometric study revealed that using AHES rather than CA slightly increases the scorch time of all types of prepared nanocomposites, whereas a significant drop in the optimum curing time was seen for NBR nanocomposites containing AHES biofiller. Moreover, thermogravimetric analysis showed similar thermal stability for SBR nanocomposites containing AHES and CA fillers. Finer particle size of CA and higher porosity of AHES at high and low loading levels were respectively the main reasons for improvement of ultimate properties. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

混杂填料增强聚四氟乙烯复合材料的摩擦学性能研究

采用MM-200型摩擦磨损试验机对纳米SiC、MoS2和石墨填充聚四氟乙烯(PTFE)复合材料在干摩擦条件下与45#钢对摩时的摩擦磨损性能进行了研究,探讨了MoS2、石墨及纳米SiC的协同效应。认为纳米SiC的加入大大提高了复合材料的承载能力,石墨、MoS2的加入减少PTFE复合材料的摩擦因数。利用扫描电子显微镜(SEM)对PTFE复合材料的摩擦面进行了观察。结果表明:实验中5%nano-SiC和3%MoS2填充PTFE复合材料的摩擦磨损性能最好,且在高载荷下的摩擦磨损性能尤为突出,具有一定的应用价值。     

Effects of small molecule plasticizer on the coordination crosslinking reaction between acrylonitrile‐butadiene rubber and copper sulfate

The effects of small molecule plasticizer of liquid acrylonitrile‐butadiene rubber (LNBR) on coordination crosslinking reaction between acrylonitrile‐butadiene rubber (NBR) and copper sulfate (CuSO₄) were investigated. Attenuated total reflectance infrared (ATR‐IR), curing curves analysis, equilibrium swelling method, differential scanning calorimetry (DSC), tensile test, and scanning electron microscope (SEM) were used in this work. The ATR‐IR analysis showed that the peak of restricted  CN is more explicit in NBR/CuSO₄/LNBR system. The curing curve analysis showed that NBR/CuSO₄/LNBR has higher torque. The results of equilibrium swelling method and DSC displayed that NBR/CuSO₄/LNBR has higher crosslink density and glass transition temperature, respectively. And NBR/CuSO₄/LNBR has stronger tensile strength and longer elongation at break from tensile test. SEM revealed the reasons that the NBR/CuSO₄/LNBR has better mechanical properties. All the results showed that addition of an amount of LNBR to NBR/CuSO₄ system could accelerate the coordination crosslinking reaction between NBR and CuSO₄. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers     

粉状填充剂对橡胶复合材料拉断伸长率的影响

以不同粒径的氢氧化镁、轻质碳酸钙和炭黑N110填充SBR、EPDM、NBR和硅橡胶，探讨粉状填充剂（简称粉体）对其填充橡胶复合材料拉断伸长率的影响。结果表明，粉体的表面活性、粒径、分散性、用量以及基体橡胶的拉伸强度和拉断伸长率等因素对橡胶复合材料拉断伸长率的影响存在着竞争关系。粉体的粒径和基体橡胶的交联密度影响橡胶复合材料拉断伸长率随粉体用量增大而提高的幅度。粉体对基体橡胶表现出较强的补强作用时，使橡胶复合材料的拉断伸长率出现峰值的粉体用量较小。与传统观点不同，试验得出大多数情况下填充粉体有利于橡胶复合材料拉断伸长率提高的结论。     

Friction and wear properties of NBR/PVC composites

Acrylonitrial butadiene rubber (NBR)/Polyvinyl chloride (PVC) composites with different PVC content were prepared. The effect of PVC content on the mechanical strength and tribological properties of the NBR/PVC composites was investigated. The morphologies of the worn traces and debris of NBR/PVC composites and worn traces of mating ball were observed using a scanning electron microscope (SEM). It was found that the friction and wear of NBR/PVC was lower than that of NBR without PVC. The NBR/PVC composite with 30% PVC content showed the best synthetic mechanical and tribological properties. The inferior elastic properties and the lesser deformation under the applied load of composites with PVC resulted in hysteric force and adhesion force decrease, which leading to a lower friction and wear of NBR/PVC composites. The frictional failure unit of NBR70/PVC30 composite being smaller should be an important reason of the wear of the composite being lowest. The lubricating effect of PVC played an important role in decreasing the friction coefficient and wear of NBR/PVC composites. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

Enhancement of the mechanical and tribological properties of carboxylated acrylonitrile butadiene rubber filled with cryptocrystalline graphite by different preparation methods

As a cost-effective and environmentally friendly natural mineral, cryptocrystalline graphite (CG) is applied in rubber materials and its performance has been evaluated. In this work, the filler dispersion and mechanical and tribological properties of carboxylated acrylonitrile butadiene rubber (XNBR)/CG composites by different preparation methods were studied. XNBR/CG composites prepared by latex blending (XNBR/CG-L) exhibited better mechanical and tribological performance, higher toughness, and lower heat build-up than those prepared by mechanical blending (XNBR/CG-M). These differences were ascribed to the filler dispersion degree, filler amount and dispersed size, and also filler–rubber interfacial interaction. Adding CG was conducive to improving the stability of the friction coefficient and reduced the wear rate via the formation of graphite lubricant and transfer films. The tribological performance of XNBR/CG-L was superior to that of XNBR/CG-M because of the improved tensile strength, tear resistance, and toughness as well as lower temperature rise. Scanning electron microscopy (SEM) and optical microscope observation showed a smoother worn surface, less and smaller wear debris of XNBR/CG-L, and a more uniform transfer film on the steel counterpart surface. The relevant results provided new insight into the performance and structural design of CG/rubber composites.     

PPESK/TK/石墨复合材料的摩擦磨损性能研究

以含二氮杂萘联苯型聚醚砜酮(PPESK)树脂为基体,以石墨和钛酸钾晶须(TK)为填料,采用物理混合、热压模塑的方法制备了PPESK/TK/石墨复合材料。研究了石墨和TK含量对复合材料摩擦磨损性能的影响,利用扫描电镜观察了磨面的形貌。结果表明,石墨和TK均能显著改善聚合物材料的摩擦磨损性能,并具有明显的协同作用。石墨对降低材料的摩擦系数起主导作用,仅以石墨为填料,材料的摩擦系数可降低至纯树脂的1/3;而TK对复合材料的磨损性能起到了明显的改善作用,当TK和石墨比例为3∶1时,材料的磨损率可降至最低,比纯树脂降低了两个数量级。扫描电镜观察结果表明材料的磨损机理主要为磨粒磨损、粘着磨损和轻微的疲劳磨损。     

Design and preparation of cross‐linked α‐methylstyrene‐acrylonitrile copolymer nano‐particles for elastomer reinforcement

Crosslinked α‐methylstyrene and acrylonitrile (MStAN) copolymer particles in a latex form were synthesized by free radical emulsion polymerization. The particles took a spherical shape with an average size of 53.1 nm in a narrow distribution. When filled into styrene‐butadiene rubber (SBR), nitrile‐butadiene rubber (NBR), and natural rubber (NR), the MStAN nano‐particles exhibited excellent reinforcing capabilities and the best in NBR. By the employment of heat treatment, mechanical properties of the MStAN‐filled SBR composites had got remarkable further improvements. But mechanical properties, together with the morphology, of the MStAN‐filled NBR composites, varied little after heat treatment, which, however, divulged the naturally good compatibility between the MStAN particles and the NBR matrix. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Improvement of the homogeneity of SBR/NBR blends using polyglycidylmethacrylate‐g‐butadiene rubber

Polyglycidylmethacrylate grafted butadiene rubber (PGMA‐g‐BR) was synthesized by a graft solution copolymerization technique. The PGMA content was determined through titration against HBr. The PGMA‐g‐BR was blended with styrene butadiene rubber/butadiene acrylonitrile rubber (SBR/NBR) blends with different blend ratios. The SBR/NBR (50/50) blend was selected to examine the compatibility of such blends. Compatibility was examined using scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and viscosity measurements. The scanning electron micrographs illustrate the change of morphology of the SBR/NBR rubber blend as a result of the incorporation of PGMA‐g‐BR onto that blend. The T_gs of SBR and NBR in the blend get closer upon incorporation of PGMA‐g‐BR 10 phr, which indicates improvement in blend homogeneity. The intrinsic viscosity (η) versus blend ratio graph shows a straight‐line relationship, indicating some degree of compatibility. Thermal stability of the compatibilized and uncompatibilized rubber blend vulcanizates was investigated by determination of the physicomechanical properties before and after accelerated thermal aging. Of all the vulcanizates with different blend ratios under investigation, the SBR/NBR (25/75) compatibilized blend possessed the best thermal stability. However, the SBR/NBR (75/25) compatibilized blend possessed the best swelling performance in brake fluid. The effect of various combinations of inorganic fillers on the physicomechanical properties of that blend, before and after accelerated thermal aging, was studied in the presence and absence of PGMA‐g‐BR. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 1559–1567, 2006     

Composites based on CB/CF/Ag filled EPDM/NBR rubber blends with high conductivity

For many applications of conductive rubbers, it is desirable to endow the conductive rubber with high conductivity at low conductive filler loading. In this work, composites based on ethylene‐propylene‐diene monomer (EPDM) rubber and nitrile‐butadiene rubber (NBR) were prepared using carbon blacks, carbon fibers, and silver powders as fillers. As the weight fraction of silver powder increased, the hardness of composites increased gradually while the tensile strength and elongation at break decreased. SEM revealed that the EPDM/NBR blends exhibited a relatively co‐continuous morphology. The differential scanning calorimetry (DSC) curves reported the EPDM/NBR rubber blends were incompatibility. The thermogravimetry (TG) studies showed that adding a small amount of silver powder could improve the thermal stability of composites. These conductive composites exhibited good electrical property. At room temperature, when the total volume fraction of fillers was 15.20%, the volume resistivity of EPDM/NBR blend was only 0.0058 Ω cm. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41357.     

聚苯硫醚复合材料摩擦性能的研究

考察了聚四氟乙烯（PTFE）、纳米无机粒子及不同含量和粒度的石墨填充改性聚苯硫醚（PPS）复合材料的摩擦磨损性能、力学性能；并采用扫描电镜（SEM）观测了磨损表面及对摩面的微观结构。结果表明：石墨的添加有利于在对摩面上形成转移物，而且随着石墨含量的增加，材料的摩擦系数明显降低，但磨耗量却有所升高，而石墨的粒度变化对材料的摩擦性能没有太大的影响；当PTFE和石墨两种固体润滑剂同时加入时，材料的力学强度有所降低，但其摩擦系数及磨耗量都得到明显改善，材料以疲劳磨损为主：纳米无机粒子的加入会使材料的磨耗量有所增大，其磨损机理转变为磨粒磨损。     

Role of fillers on three‐body abrasive wear behavior of glass fabric reinforced epoxy composites

The article summarizes an experimental study on the abrasive wear behavior of particulate filled glass‐epoxy (G‐E) composites. The two fillers investigated were graphite and alumina. The wear behavior was assessed by rubber wheel abrasion tests. The tests were carried out for 270, 540, 810, and 1080 m abrading distances at 22 and 32 N loads. The worn surfaces were examined using scanning electron microscopy (SEM). The results showed varied responses under different abrading distance because of the addition of fillers in G‐E composites. Graphite filler, however, performed poorly resulting in significant deterioration in wear performance while the alumina filled G‐E composite showed improved abrasion resistance. Selected mechanical properties such as hardness, tensile strength, and elongation at fracture were analyzed for investigating wear property correlations. The SEM studies indicate the reasons for failure of composites and influencing parameters. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers     

MWCNT/Hectorite hybrid filled acrylonitrile butadiene rubber/ ethylene-co-vinyl acetate blend nanocomposites: preparation and properties

Multiwalled carbon nanotube/hectorite hybrid filler (HMH) was prepared by simple dry grinding method. It was subsequently used for the reinforcement of technologically compatible acrylonitrile butadiene rubber (NBR)/ ethylene-co-vinyl acetate (EVA) blend through solution intercalation method. Analysis of the prepared blend nanocomposites confirms homogeneous dispersion of the constituent fillers in the polymer matrix and significant interaction between two types of constituent fillers. Mechanical properties of NBR/EVA blend are significantly improved with HMH content up to 4 wt.% followed by reversion. Maximum improvement observed in tensile strength, elongation at break and toughness are 106%, 37% and 171% respectively without significant rise in Young’s modulus. Results also show best dynamic mechanical and dielectric response at 4 wt.% and 3 wt.% HMH content respectively. Enhanced mechanical, dynamic mechanical and dielectric properties of the blend nanocomposites attained may be attributed to fair degree of compatibility between the two polymer matrices, homogeneous dispersion of fillers and improved polymer-filler interaction.