Comparison of morphology and mechanical properties of peroxide‐cured acrylonitrile butadiene rubber/LDH composites prepared from different organically modified LDHs

Rubber compounds based on acrylonitrile butadiene rubber (NBR) containing organically modified layered double hydroxides (LDHs) were prepared using peroxide as a curing agent. The LDHs intercalated by organic compounds including sodium styrene sulfonate (SSS) and sodium dodecylbenzene sulfonate (SDBS) were investigated using thermogravimetric analysis (TGA) and X‐ray diffraction (XRD) while the unmodified LDHs were used as contrast. Experimental results from TGA and XRD showed that both SSS‐ and SDBS‐intercalated LDHs were successfully obtained. The morphology of the LDH composites was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and XRD. The chemical structure of NBR/LDHs compounds were measured by Fourier transform infrared spectrum. The thermal properties were measured by TGA and differential scanning calorimetry. Other properties such as mechanical and swelling properties were also investigated. The results showed that a chemical bonding between organically modified LDHs and rubber matrix through SSS was built during vulcanization, which leads to improved interfacial strength of the cured compound. A high‐performance acrylonitrile butadiene rubber/SSS‐modified LDH compound, which has two times higher tensile strength than cured pure rubber without significant loss of elongation, was obtained. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

改性Kevlar纳米纤维对羧基丁腈橡胶/丁苯橡胶共混胶力学性能的影响

采用环氧氯丙烷对Kevlar纳米纤维(KNFs)表面进行改性,制备了表面改性KNFs(m-KNFs),考察了m-KNFs对羧基丁腈橡胶(XNBR)/丁苯橡胶(SBR)共混胶力学性能的影响.结果表明,m-KNFs可以增强XNBR/SBR共混胶的拉伸性能及撕裂性能,提高硫化胶的热稳定性和耐溶剂性能.添加5份m-KNFs后,...     

纳米碳酸钙丁腈橡胶母炼胶的制备及性能评价

采用乳液法制备了丁腈橡胶（NBR）/纳米碳酸钙（NCC）共沉橡胶,并对其性能进行了评价。基本性能实验结果表明：与NBR相比,共沉胶焦烧时间略有降低,正硫化时间略有增加,最大扭矩明显提高,共沉胶具有优异的基本物理性能;工业配方配合显示：共沉胶具有优异的基本物理性能、耐热空气老化性能以及耐热油性能;共沉胶成本明显降低,具有良好的应用前景。     

丁腈橡胶/铌镁锆钛酸铅/碳纤维复合材料的介电性能和压电性能

以丁腈橡胶(NBR)为基体,铌镁锆钛酸铅(PMN)粉体为分散相,碳纤维(CF)为导电填料,制备了压电复合材料,研究了复合材料的压电性能及介电性能。结果表明,80%以上PMN粒子的粒径为0.5~2.0μm,填充密度约为6.6g/cm3;当填充CF体积分数小于5%时,复合材料的击穿电压受填充CF用量的变化影响不大,当填充CF体积分数达到10%时,复合材料的击穿电压下降到未填充CF复合材料的1/3~1/2,填充CF最佳体积分数为5%;当填充PMN体积分数增至40%后,复合材料的纵向压电应变常数(d33)随PMN用量的增加而增大;适当地延长极化时间和增加极化电压有利于提高d33,最佳极化电压为7kV/mm,最佳极化时间为25min;复合材料的介电常数(ε)随填充PMN用量的增加而增大;当CF用量为0时,复合材料的ε与介电损耗(tanδ)的变化趋势相反;当填充CF体积分数为5%时,复合材料不但具有较高的ε,而且具有较高的tanδ。     

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     

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.     

无皂乳液聚合制备丁二烯-丙烯腈橡胶

采用硫酸盐类可聚合乳化剂烯丙氧基壬基苯氧基丙醇聚氧乙烯醚硫酸铵（KD SE-10）通过低温乳液聚合法制备无皂丁腈橡胶。详细考察了可聚合乳化剂用量对门尼粘度、结合丙烯腈含量、凝胶量、拉伸强度、相对分子质量的影响情况,并确定了KD SE-10用量为2.7%～3.0%（质量分数）。制得的无皂丁腈橡胶相比普通丁腈橡胶具有显著的高强度、更优良的耐油性、相对分子质量分布窄的特点。     

Aluminum silicate fibers impregnated acrylonitrile butadiene rubber composites: Ablation,thermal transport/stability,and mechanical inspection

Variant concentrations of ceramic fibers (CerFs) were incorporated into acrylonitrile butadiene rubber (NBR) to fabricate elastomeric ablative composites for ultrahigh temperature applications. The CerFs introduction into the polymer matrix has enhanced the ablation resistance up to 59% and successfully reduced the backface temperature of the polymer composite up to 110^oC during the ultrahigh temperature ablation investigation. Thermal decomposition of the polymer composites was diminished up to 10% with increasing fiber concentration in the rubber matrix. Thermal conductivity was reduced equal to 63% while thermal impedance was enhanced up to 84% with the utmost fiber incorporation into the NBR matrix. The CerFs have adversely affected the mechanical properties of NBR matrix due to their brittle/inert nature and weak interface bonding with the host matrix. Scanning electron microscopy along with the energy dispersive x‐ray spectroscopy was used to examine the ablated specimens and the fiber dispersion within the host matrix. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 4392–4400, 2013     

Compatibility study of polypropylene and acrylonitrile butadiene rubber blends

Blends of polypropylene (PP) and acrylonitrile butadiene rubber (NBR) were prepared with different weight compositions with a plasticorder at 180°C at a rotor speed of 60 rpm for 8 min. The physicomechanical properties and mass swell of the prepared blends were investigated with special reference to the effects of the blend ratio. The prepared epoxidized linseed oil (EL) (i.e., E_0.5L, E₁L, E_1.5L, and E₂L using 0.5, 1, 1.5, and 2 mol H₂O₂/mole of unsaturation in linseed oil) and maleic acid anhydride (MAH) were melt mixed in various contents (i.e., 1, 5, 10, and 15 wt %) with a PP/NBR blend with a weight ratio of 70/30 and used as compatibilizers. The effect of the compatibilizer contents on the physicomechanical properties and mass swell of the binary blend was investigated. With an increase in the compatibilizer content up to 10 wt %, the blend showed an improvement in the physicomechanical properties and reduced mass swell in comparison with the uncompatibilized one. The addition of a compatibilizer beyond 10 wt % did not improve the blend properties any further. The efficiency of the compatibilizers (10 wt %) was also evaluated by studies of phase morphology (scanning electron microscopy). © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Enhancement of mechanical strength associated with interfacial tension between barium titanate and acrylonitrile–butadiene rubber with different acrylonitrile contents by surface modification

Acrylonitrile–butadiene rubber (NBR) with different acrylonitrile (ACN) contents was filled with barium titanate (BT) to prepare the polymer dielectrics. The neat NBR, NBR/untreated BT, and NBR/bis‐(γ‐triethoxysilylpropyl)‐tetrasulfide (silane coupling agent KH845‐4) modified BT (MBT) composites were prepared. At low ACN content (ACN content 20 wt %), the tensile strength of the NBR/MBT composites increased by 173.6% from 2.69 to 7.36 MPa compared to the neat NBR. The pleasing results were not found in those composites with high ACN content. Both surface modifications of BT and NBR with low ACN content would result in lower interfacial tension between BT and NBR. A strong interfacial adhesion was observed between MBT and NBR with 20 wt % ACN content. The interfacial adhesion had great contribution to the mechanical strength of composites. Moreover, the dielectric properties of composites were also investigated in detail. The addition of BT enhanced the dielectric constant of composites markedly. This study can be applied in manufacturing electronic devices, which are subjected to oily environments for a long time. At the same time, the study can provide some help for researchers to select the polymer matrix and the appropriate surface modification agent of functional filler. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45936.     

Niobium oxide-activated yttrium barium titanate nanorod structured ceramics for energy storage applications

Structure, morphology, and electrical properties of 10 mol% of Nb₂O₅-activated yttrium barium titanate (BT) Ba_(60-z)Ti_(40-x)Nb_zY_xO₃ (BTY₁₀Nb₁₀), barium titanate (BT), and 10 mol% of Y₂O₃-activated BT were explored with calcination and sintering temperatures of 1000°C at 8 h and 1200°C at 6 h, respectively. The thermogravimetric and differential scanning calorimetry (TG–DSC) analysis reported that the total weight loss and residual mass of BT at 1300°C were 16.8 and 83.2%, respectively. The X-ray diffraction (XRD) pattern confirmed that BTY₁₀Nb₁₀ ceramics containing the BaNbO₃ phase were developed. A Raman band of BT at 307 cm^–1 unveiled a blue shift slightly for BTY₁₀ to 298 cm^–1 and for BTY₁₀Nb₁₀ to 306 cm^–1. Average pore area of the ferroelectric BTY₁₀Nb₁₀ was found to be 6.96 nm for the total scanning electron microscopy (SEM) image area of 20.31 nm. Formation of BT nanorods analyzed from transmission electron microscopy (TEM) has been reported in three samples that regulate surface roughness. Moreover, Nyquist diagram of BTY₁₀Nb₁₀ shows two overlapping semicircles as a function of frequency. Nanorod structures led to change the morphology and surface roughness. Recoverable energy storage density and energy storage efficiency were estimated as 2.63 µJ/cm³ and 57%, and BTY₁₀Nb₁₀ ferroelectric showed potential for energy storage applications due to changes in surface morphology and porosity.     

Enhancement of electromechanical properties of natural rubber by adding barium titanate filler: An electro-mechanical study

Natural rubber is one of the most potential electro-active polymers for sensors, actuators, and energy harvesting applications. Enhancing the characteristic properties of polymers by reinforcing with fillers that possess multifunctional attributes have attracted considerable attention. In the present study, barium titanate reinforced natural rubber composite is prepared by using two-roll mill mixing. Afterwards, mechanical, electrical, and electromechanical properties of the composites are extensively analyzed by reinforcing different amounts of barium titanate into the matrix of natural rubber. The fabricated dielectric composite shows excellent properties such as high dielectric constant, low dielectric losses, high dielectric breakdown strength, and extreme stretchability. It is observed that as the filler loading reaches the value of 11 parts per hundred rubber (phr), maximum agglomeration of the particles occurs. Maximum stretchability and highest ratio of dielectric constant to elastic modulus are obtained at 8 phr of barium titanate fillers and at the loading, a maximum actuation strain of 11.24% is achieved. This study provides a simple, economical, and effective method for preparing enhanced mechanical, electrical, and electromechanical properties of natural rubber composites, facilitating the wide applications of dielectric materials as actuators and generators.     

Preparation of epoxidized acrylonitrile butadiene rubber and its compatibilization effect on water-swellable rubber composites

In this research, water-swellable rubbers (WSRs) were prepared by the blending of acrylonitrile butadiene rubber (NBR) with epoxidized acrylonitrile butadiene rubber (ENBR), precipitated silica, vulcanizing agents, and polyacrylic acid sodium (PAAS) as superabsorbent polymers (SAPs). ENBR was prepared with a molybdenum trioxide catalyst and a tert-butyl hydroperoxide oxidant through a free-radical reaction under specific conditions and was used as a compatibilizer to improve the interfacial adhesion of the NBR matrix and hydrophilic components of the WSRs. Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy were used to analyze the structure and properties of ENBR. The dispersion of silica and SAPs in the rubber matrix was investigated by transmission electron microscopy. The presence of ENBR enhanced the water-absorption properties of the WSRs. The NBR–ENBR composites exhibited a higher mechanical performance after water absorption than that without ENBR. Both the swelling ratio and the absorption rate increased with the ENBR content. When the weight ratio of NBR–ENBR was 25/75, an equilibrium swelling ratio of 172% (13% higher than that of the sample without ENBR) was obtained. Scanning electron microscopy analysis revealed that the addition of ENBR improved the compatibility between the SAPs and the NBR matrix. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47694.     

钛酸钡纳米复合材料制备与性能研究

对钛酸钡颗粒进行羟基化和巯基官能化处理,将纳米银粒子成功接枝到钛酸钡颗粒表面制备了x Ag@BT颗粒(x为银质量分数,BT为钛酸钡),并用溶液共混法制备了Ag@BT/PVDF纳米复合材料(PVDF为聚偏氟乙烯)。结果表明,x Ag@BT颗粒为具有草莓结构的纳米颗粒,尺寸为2~16 nm的银粒子成功装饰在钛酸钡颗粒表面;纳米银粒子的引入可以降低复合材料在低频下的介电损耗和电导率,且当纳米银粒子质量分数为1.0%时复合材料的特征击穿强度达到最大值;与传统BT/PVDF纳米复合材料相比,1.0%Ag@BT/PVDF纳米复合材料具有更优良的电性能。     

端氨基丁腈橡胶增韧环氧-聚酰胺胶粘剂的研究

通过DSC,扫描电镜分析及剪切和剥离强度性能测试研究了端氨基液体丁腈橡胶(ATBN)改性环氧-聚酰胺体系的固化动力学,粘接性能及增韧相态。结果表明,根据Ellerstein法和峰值法计算得到的固化反应活化能分别为为73.6 kJ/mol和65.7 kJ/mol,体系最佳固化温度为41～97℃。固化体系中橡胶相粒径大小对胶粘剂性能有较大影响,60℃和室温固化体系分散相粒子平均粒径分别为1～2μm,0.5μm。粒径1～2μm时体系的增韧效果最佳,粘接性能优异。     

Natural rubber/nitrile butadiene rubber/hindered phenol composites with high-damping properties

New natural rubber (NR)/nitrile butadiene rubber (NBR)/hindered phenol (AO-80) composites with high-damping properties were prepared in this study. The morphological, structural, and mechanical properties were characterized by atomic force microscopy (AFM), polarized Fourier transform infrared spectrometer (FTIR), dynamic mechanical thermal analyzer (DMTA), and a tensile tester. Each composite consisted of two phases: the NR phase and the NBR/AO-80 phase. There was partial compatibility between the NR phase and the NBR/AO-80 phase, and the NR/NBR/AO-80 (50/50/20) composite exhibited a co-continuous morphology. Strain-induced crystallization occurred in the NR phase at strains higher than 200%, and strain-induced orientation appeared in the NBR/AO-80 phase with the increase of strain from 100% to 500%. The composites had a special stress–strain behavior and mechanical properties because of the simultaneous strain-induced orientation and strain-induced crystallization. In the working temperature range of a seismic isolation bearing, the composites (especially the NR/NBR/AO-80 (50/50/20) composite) presented a high loss factor, high area of loss peak (TA), and high hysteresis energy. Therefore, the NR/NBR/AO-80 rubber composites are expected to have important application as a high-performance damping material for rubber bearing.     

Properties of silica‐filled styrene‐butadiene rubber compounds containing acrylonitrile‐butadiene rubber: The influence of the acrylonitrile‐butadiene rubber type

Because silica has strong filler‐filler interactions and adsorbs polar materials, a silica‐filled rubber compound exhibits poor dispersion of the filler and poor cure characteristics in comparison with those of a carbon black‐filled rubber compound. Acrylonitrile‐butadiene rubber (NBR) improves filler dispersion in silica‐filled styrene‐butadiene rubber (SBR) compounds. The influence of the NBR type on the properties of silica‐filled SBR compounds containing NBR was studied with NBRs of various acrylonitrile contents. The composition of the bound rubber was different from that of the compounded rubber. The NBR content of the bound rubber was higher than that of the compounded rubber; this became clearer for NBR with a higher acrylonitrile content. The Mooney scorch time and cure rate became faster as the acrylonitrile content in NBR increased. The modulus increased with an increase in the acrylonitrile content of NBR because the crosslink density increased. The experimental results could be explained by interactions of the nitrile group of NBR with silica. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 385–393, 2002     

The effects of filler content on cure and mechanical properties of dichlorocarbene modified styrene butadiene rubber/carbon black composites

A study has been carried out on the curing characteristics and mechanical properties of carbon black filled dichlorocarbene modified styrene butadiene rubber (DCSBR). Processing characteristics such as optimum cure time and maximum torque increases with increasing of the concentration of carbon black in DCSBR whereas scorch time decreases. The mechanical properties and resistance of the vulcanizate towards thermal, flame and oil resistance have been carried out. Variation of bound rubber content of carbon black filled DCSBR and the influence of the extracting temperature on the bound rubber content was investigated and its activation energy was calculated from the Arrhenius plot. The reinforcing nature of the filler was assessed from stress strain and swelling data. The enhancement in mechanical properties was supported by data on the increased content of crosslink density in these samples obtained from swelling and stress strain analysis. The results of the studies indicate that carbon black can be used as a good reinforcing filler for DCSBR.     

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。     

Effect of carbon black on the mechanical and dielectric properties of rubber ferrite composites containing barium ferrite

Fine particles of barium ferrite (BaFe₁₂O₁₉) were synthesized by the conventional ceramic technique. These materials were then characterized by the X‐ray diffraction method and incorporated in the natural rubber matrix according to a specific receipe for various loadings of ferrite. The rubber ferrite composites (RFC) thus obtained have several applications, and have the advantage of molding into complex shapes. For applications such as microwave absorbers, these composites should have an appropriate dielectric strength with the required mechanical and magnetic properties. The N330 (HAF) carbon black has been added to these RFCs for various loadings to modify the dielectric and mechanical properties. In this article we report the effect of carbon black on the mechanical and dielectric properties of these RFCs. Both the mechanical and dielectric properties can be enhanced by the addition of an appropriate amount of carbon black. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 769–778, 2003