Investigation on the mechanical properties and oil resistance of sulfur cured nitrile rubber/hydrogenated nitrile butadiene rubber blends

Nitrile rubber (NBR)/hydrogenated nitrile butadiene rubber (HNBR) blends with various ratios were compounded with internal mixer and two-roll open mill. Mechanical properties and low-temperature performance (TR10) of the NBR/HNBR blends after aging under different conditions were investigated. Furthermore, equilibrium swelling test and moving die rheometer (MDR) test were used to systematically investigate the effects of HNBR dosage on the crosslink densities and curing behaviors. Vulcanization torque and crosslink densities decreased with an increase in HNBR content. The crosslink density of pure HNBR is higher than that of pure NBR, which is related to the macromolecular structures of the rubber. Compression sets of the NBR/HNBR vulcanizates were correlated with HNBR dosage indicating a linear relationship. Low-temperature performance of the NBR/HNBR blends was improved after being aged in the synthetic hydrocarbon hydraulic oils (SH-1 and SH-2). This work shows that the low-temperature performance and oil resistance could be better balanced by blending NBR with HNBR, while the mechanical properties maintain relatively high level.     

Effect of different nanoparticles on thermal,mechanical and dynamic mechanical properties of hydrogenated nitrile butadiene rubber nanocomposites

Organically modified and unmodified montmorillonite clays (Cloisite NA, Cloisite 30B and Cloisite 15A), sepiolite (Pangel B20) and nanosilica (Aerosil 300) were incorporated into hydrogenated nitrile rubber (HNBR) matrix by solution process in order to study the effect of these nanofillers on thermal, mechanical and dynamic mechanical properties of HNBR. It was found that on addition of only 4 phr of nanofiller to neat HNBR, the temperature at which maximum degradation took place (T_max) increased by 4 to 16°C, while the modulus at 100% elongation and the tensile strength were enhanced by almost 40–60% and 100–300% respectively, depending upon nature of the nanofiller. It was further observed that T_max was the highest in the case of nanosilica‐based nanocomposite with 4 phr of filler loading. The increment of storage modulus was highest for sepiolite‐HNBR and Cloisite 30B‐HNBR nanocomposites at 25°C, while the modulus at 100% elongation was found maximum for sepiolite‐HNBR nanocomposite at the same loading. A similar trend was observed in the case of another grade of HNBR having similar ACN content, but different diene level. The results were explained by x‐ray diffraction, transmission electron microscopy, and atomic force microscopy studies. The above results were further explained with the help of thermodynamics. Effect of different filler loadings (2, 4, 6, 8, and 16 phr) on the properties of HNBR nanocomposites was further investigated. Both thermal as well as mechanical properties were found to be highest at 8 phr of filler loading. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Properties of tire tread compounds based on functionalized styrene butadiene rubber and functionalized natural rubber

Tire tread compounds based on various rubber types, that is, solution styrene-butadiene rubber (SSBR), functionalized (propylamine and dimethoxysilane) solution styrene-butadiene rubber (F-SSBR), natural rubber (NR), chloroacetate-modified natural rubber (CNR), and their blends, were prepared and used as raw rubbers. Properties of tire tread compounds and tire performance were then investigated. Due to the presence of chloroacetate group on its mainchains, CNR demonstrates increases in glass transition temperature and rubber-filler interaction compared to NR leading to a significant improvement in tire performance, particularly wet grip (WG; ~88%), fuel-saving efficiency (FSE; ~15%), and abrasion resistance (~11%). Similarly, F-SSBR shows a greater tire performance than SSBR (~20, ~13, and ~7% improvements in WG, FSE, and abrasion resistance, respectively). Among the rubber blends, F-SSBR/CNR gives the highest tire performance, followed by F-SSBR/NR, SSBR/CNR, and SSBR/NR, respectively. The results suggest the significant enhancement in properties of tire tread compounds by the presence of active functional groups in NR and SSBR molecules. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 137, 48696.     

Effects of crosslinking densities on mechanical properties of nitrile rubber composites in thermal oxidative aging environment

The effects of crosslinking densities on mechanical properties of nitrile rubber (NBR) composites before and after thermal oxidative aging are investigated. Tensile strengths of NBR composites are enhanced slightly at the initial aging stage, attributing to moderate increment of crosslinking densities. Continuous decrease with further aging is followed, resulting from over-crosslinking and uneven distribution of crosslinking densities. The digital image correlation method is explored for large-strain deformation measurement by displacement accumulation and establishing strain model, being promising in practical age detection and measurement of mechanical properties in complex environments. Compression sets are gradually increased with aging because of the destruction of the original crosslinking structures. The molecular chains fracture inhibits elastic recoveries of compressive NBR composites and results in residual deformation in thermo-oxidative and compressive environment after unloading. This study provides new ideas for exploring mechanical properties of rubber-based composites before and after thermal oxidative aging.     

共混比对丁腈橡胶/氯醚橡胶性能的影响

研究了共混比时常规共混及动态硫化共混丁腈橡胶(NBR)／氯醚橡胶(ECO)的力学性能及加工流变性能的影响。结果表明,共混比对NBR／ECO胶料的力学性能及加工流变性能影响显著。NBR经动态硫化后,压缩永久变形及挤出胀大明显减小,拉伸强度提高,表现黏度随ECO用量的增大而减小。共混比对常规共混胶的表观黏度影响不大。动态硫化有利于改善NBR／ECO胶料的加工性能。     

Effects of elevated temperature and crude oil on the properties of a hydrogenated nitrile butadiene rubber elastomer

The stability and durability of hydrogenated nitrile butadiene rubber (HNBR) material in crude oil environments are of great importance for petroleum equipment to resist leakage and to ensure reliability. In this paper, an HNBR material was fabricated, and the degradation of the HNBR material was investigated in simulated crude oil environments. One crude oil and three temperatures (50 °C, 75 °C, and 100 °C, based on actual crude oil operations, were used in this study. Weight changes for the HNBR specimens were monitored after exposure to the environments over time. Optical microscopy was used to show the topographical changes on the specimen surfaces. Attenuated total reflection Fourier transform infrared (ATR‐FTIR) spectroscopy was employed to study the surface chemistry of the HNBR material before and after exposure to the simulated crude oil environments at selected times. Mechanical property tests (tensile and compressive stress–strain tests, tear strength test, and compression set test) were conducted to assess the changes in mechanical properties of the HNBR specimens before and after exposure to the environments. The test results show that the physical–mechanical properties of the HNBR material changed significantly. The temperature and the crude oil had a direct effect on the degradation of the mechanical properties. The ATR‐FTIR test results indicate that the surface chemistry changed via chain crosslinking in the material after exposure to the environments over time. The degradation mechanisms of the HNBR material after exposure to the crude oil could be due to the presence of chain crosslinking, chain mobility, and backbone scission. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44012.     

硫化体系对氢化丁腈胶热氧老化性能的影响

系统研究了不同硫化体系对氢化丁腈胶（HNBR）力学性能和热氧老化性能的影响。结果表明：采用过氧化物/硫磺（S）体系得到的胶料其综合性能优于过氧化物体系得到的胶料,在100份HNBR中加入5份过氧化二异丙苯（DCP）和0.5份S,即DCP与S并用时,硫化胶拉伸强度可以达到23.85 MPa,在160℃×72 h热氧老化后仍可以达到20.99 MPa。热氧老化性能以DCP/S为7/0.5时最为优异。     

Multi-walled carbon nanotube reinforced self-crosslinking hydrogenated carboxylated nitrile butadiene rubber latex film with improved properties

A dielectric self-crosslinking hydrogenated carboxylated nitrile butadiene rubber (HXNBR) latex film was prepared by diimide reduction hydrogenation of XNBR latex and the doping of multi-walled carbon nanotube (MWCNT). The structures of the HXNBR and XNBR were characterised by Fourier transform infrared spectroscopy (FTIR) and ¹HNMR, confirming the successful hydrogenation of XNBR. The mechanical, thermal, and electrical properties of the prepared HXNBR latex films were studied, and the HXNBR latex film reinforced by only 3?phr MWCNTs exhibited improved mechanical, thermal, and dielectric properties.     

氢化丁腈橡胶耐热老化性能的研究

研究了几种不同类型的防老剂对HNBR耐热空气老化的影响。结果表明,采用防老剂RD与MB并用体系硫化胶的综合性能最好;100份生胶中加入1份防老剂RD和1份防老剂MB,在170℃／15MPaxt90的条件下硫化后硫化胶的拉伸强度为28．3MPa,180℃热空气老化24h后其拉伸强度为274MPa,老化48h后其拉伸强度仍然可迭172MPa。     

Acoustic properties of nitrile butadiene rubber for underwater applications

Acoustic properties of nitrile butadiene rubber (NBR) specimens with carbon black as filler were investigated with different sulfur contents in the frequency range of 300‐1000 kHz. Their mechanical properties, such as density, hardness, tensile strength, were conventionally measured and correlated with their acoustic properties. Sound speeds in the specimens were increased with an increase in the sulfur content. The variation of sound speed was about 2–5% in the specimens, whereas the variation of density was less than 0.4%. Enhanced acoustic transmission was also observed with increasing sulfur content. It may be due to the hardness change from the increase of crosslinking density in the specimens. These results show that the mechanical properties of NBR can be nondestructively and accurately determined with the acoustic property measurements. By use of the desired mechanical and acoustic properties, the utilization of the NBR for underwater applications becomes less d ficult. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 2764–2771, 2002     

增强氢化丁腈橡胶的结构与性能

研究了甲基丙烯酸锌(ZDMA)、SiO,和炭黑N 550分别填充氢化丁腈橡胶(HNBR)的流动性、硫化特性、物理机械性能、耐老化性能、压缩永久变形及动态力学性能,表征了填料在HNBR混炼胶及硫化胶中的形态结构.结果表明,3种填料填充的HNBR混炼胶均属非牛顿流体,其中ZDMA填充HNBR混炼胶具有较好的流动性;经过二段硫化后.3种填料填充HNBR具有较佳的物理机械性能、耐老化性能和耐压缩性能;zDMA和SiO2,对HNBR的增强效果显著,但HNBR硫化胶的压缩永久变形偏高,N 550填充HNBR硫化胶的扯断伸长率和压缩永久变形较低;SiO2填充HNBR混炼胶和硫化胶的Payne效应较ZDMA、N 550填充HNBR混炼胶和硫化胶显著;N 550、SiO2种填料在HNBR混炼胶和硫化胶中均能达到纳米尺度,ZDMA在HNBR混炼胶中呈微米尺度,而在HNBR硫化胶中呈纳米尺度.     

氢化丁腈橡胶的结构与阻尼性能的关系

通过应力-应变曲线和动态力学性能分析(DMTA),探讨了氢化丁腈橡胶(HNBR)的结构、阻尼性能及其之间的关系.结果表明,HNBR的结合丙烯腈量越高,胶料的弹性越差,阻尼性能越好;双键含量升高,玻璃化转变温度降低,弹性增加.与应力-应变曲线相比,DMTA能更全面地反映材料的阻尼性能.     

氯醚橡胶/丁腈橡胶共混物的结构与性能

研究了不同并用比的氯醚橡胶（ECO）／丁腈橡胶（NBR）共混物的相态结构,力学性能,耐老化性能和耐油性能,透射电镜照片显示：ECO／NBR为70／30（质量份,下同）时共混物呈双连续相：为60／40和40／60时ECO都为分散相,且两相界面清晰。加入NBR降低了ECO的拉伸强度和看断伸长率,以及耐热空气老化性能,随着NBR用量的提高,共混物硫化胶在油中的体积变化率增加,ECO／NBR为70／30时硫化胶在100℃热油中的性能保持率最高,而且体积变化率与ECO的相当。     

Morphology,mechanical and viscoelastic properties of nitrile rubber/epoxidized natural rubber blends

A new class of blend membranes from blends of nitrile rubber (NBR) and epoxidized natural rubber (ENR) has been prepared and their morphology, miscibility, mechanical, and viscoelastic properties have been studied. The ebonite method was used to study the blend morphology of the membranes. The morphology of the blends indicated a two‐phase structure in which the minor phase is dispersed as domains in the major continuous phase. The performance of NBR/ENR blend membranes has been studied from the mechanical measurements. The viscoelastic behavior of the blends has been analyzed from the dynamic mechanical data. An attempt was made to relate the viscoelastic behavior with the morphology of the blends. Various composite models have been used to predict the experimental viscoelastic data. The area under the linear loss modulus curve was larger than that obtained by theoretical group contribution analysis. The homogeneity of the system was further evaluated by Cole–Cole analysis. Finally, a master curve for the modulus of the blend was generated by applying the time–temperature superposition principle. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 1561–1573, 2005     

Influence of molecular parameters on thermal,mechanical, and dynamic mechanical properties of hydrogenated nitrile rubber and its nanocomposites

The present work derives a relationship between structure and properties of hydrogenated nitrile rubber (HNBR) in the presence as well as absence of nanofillers. Four different grades of HNBR were selected to examine the influence of polarity, unsaturation, and molecular weight on thermal, mechanical, and dynamic mechanical properties of the elastomers and particularly their nanocomposites. An increase in thermal stability, tensile strength, modulus at 100% elongation as well as storage modulus of the unfilled rubber was observed with increase in polarity (acrylonitrile content). Different nanofillers, such as montmorillonite, sepiolite, and nanosilica were used to improve the above properties of the unfilled rubber. Interestingly, a reverse trend of thermal properties was observed for the nanocomposites with acrylonitrile variation, although mechanical and dynamic mechanical properties exhibited similar trend to those of the unfilled rubber. These properties, however, gradually deteriorated as the level of unsaturation on the polymer backbone was increased. On addition of the nanofillers, it was found that the improvement in thermal and mechanical properties was higher for the elastomer having 5.5% diene content. The results were explained by X‐ray Diffraction, Atomic Force Microscopy, Energy Dispersive X‐ray mapping, and swelling studies. POLYM. ENG. SCI., 2010. © 2010 Society of Plastics Engineers     

国内丁腈橡胶生产情况及市场分析

综述了国内外丁腈橡胶的生产及市场情况，对国内丁腈橡胶的市场发展趋势进行了分析和预测。并针对入世后国内丁腈橡胶行业存在的不足提出了几点建议。     

助交联剂在氢化丁腈橡胶中的应用研究

研究了添加不同用量的助交联剂齐聚酯和三甲基丙烯酸三羟甲基丙烷酯(TMPTMA)氢化丁腈橡胶的硫化特性、力学性能,并对比了两种助交联剂对氢化丁腈橡胶的硫化特性、力学性能、老化性能、高温拉伸性能、耐磨性能和加工性能的影响。结果表明：随着齐聚酯和TMPTMA含量的增加,橡胶的扭矩增大,硫化时间缩短;拉伸强度基本不变,硬度、100%定伸应力、撕裂强度逐渐提高,拉断伸长率、回弹性减小。与添加齐聚酯的橡胶相比,添加TMPTMA橡胶的扭矩较大,硫化时间较短;对比添加齐聚酯和TMPTMA的橡胶,它们的力学性能、老化性能、高温拉伸性能和耐磨性能都非常接近,可见它们在硫化过程中的作用原理相似。由橡胶加工分析仪可知,添加TMPTMA橡胶的储能模量较小,损耗因子较大。     

Preparation and mechanical properties of nitrile butadiene rubber/silicate nanocomposites

Elastomer nanocomposites consisting of nitrile butadiene rubber (NBR) latex and layered silicates are prepared by a modified latex shear blending process aided with ball milling. The mode of dispersion of layered silicates in NBR is partially exfoliated and intercalated when the concentration of layered silicates is below 7.5 wt%, as evidenced by transmission electron microscopy and X-ray diffraction results. The tensile and tear mechanical properties are much higher than that of neat NBR. Specifically, the tensile and tear mechanical properties of the NBR/layered silicates increase by 200 and 60%, respectively. The decomposition temperature of the nanocomposites increases slightly.     

不同防老体系对丁腈橡胶老化前后物理机械性能及丁腈胶管扣压过程中性能变化的影响

本文主要研究了不同种类防老体系对丁腈橡胶老化前后物理机械性能及丁腈胶管扣压过程中性能变化的影响;实验结果表明:1#防老体系耐热油老化性能较好,4#防老体系耐热空气老化性能较好;仿真计算结果表明:使用1#防老体系的胶管扣压后,静刚度、应力集中单元处的应变能密度及相同节点处Mises应力较大,使用3#防老体系的胶管扣压后,静刚度、应力集中单元处的应变能密度及相同节点处Mises应力较小。