Influences of trans‐polyoctylene rubber on the physical properties and phase morphology of natural rubber/acrylonitrile–butadiene rubber blends

The influence of trans‐polyoctylene rubber (TOR) on the mechanical properties, glass‐transition behavior, and phase morphology of natural rubber (NR)/acrylonitrile–butadiene rubber (NBR) blends was investigated. With an increased TOR level, hardness, tensile modulus, and resilience increased, whereas tensile strength and elongation at break tremendously decreased. According to differential scanning calorimetry and dynamic mechanical analysis, there were two distinct glass‐transition temperatures for a 50/50 NR/NBR blend, indicating the strongly incompatible nature of the blend. When the TOR level was increased, the glass transition of NBR was strongly suppressed. NBR droplets of a few micrometers were uniformly dispersed in the continuous NR phases in the NR/NBR blends. When TOR was added to a 50/50 NR/NBR blend, TOR tended to be located in the NR phase and in some cases was positioned at the interfaces between the NBR and NR phases. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 125–134, 2002     

EPDM/NR并用胶的复合交联

采用硫黄硫化体系和过氧化物（硫化剂DCP）硫化体系对EPDM／NR并用胶实施复合交联，研究并用比和复合交联体系对胶料的硫化特性、物理性能和耐热老化性能的影响。结果表明，在大部分并用比下，复合交联可以改善胶料的硫化特性；在硫化剂DCP和助交联剂TAIC的用量均为2份、EPDM／NR／ENR并用比为30／68．5／1．5时，并用胶的物理性能优良；以NR为主的并用胶在复合交联时硫化剂DCP和助交联剂TAIC的用量宜取1～2份。     

NR/EPDM 的共硫化

利用环氧化天然橡胶(ENR)与天然橡胶(NR)和三元乙丙橡胶(EPDM)均有很好相容性的特点，采用硫化促进剂预混工艺对NR／EPDM并用胶实施共硫化。考察了其对NR／EPDM并用胶的硫化特性、硫化胶的物理机械性能和耐热空气老化性能的影响。结果表明：本工艺确实能改善NR／EPDM的共硫化性能，所得硫化胶物理性能较好且操作简单。     

Effects of trans‐polyoctylene rubber on rheological and green tensile properties of natural rubber/acrylonitrile–butadiene rubber blends

The influence of trans‐polyoctylene rubber (TOR) on the flow property, die swell behaviour and green tensile property of NR (natural rubber)/NBR (acrylonitrile–butadiene rubber) blend compound was investigated as a function of TOR loading level. The pure TOR, NR and NBR compounds were also investigated for comparison with the blend compounds. The shear viscosity of TOR strongly depended on the temperature as well as shear rate. The viscosity of the NR/NBR blend compound was even lower than that of the constituent components at relatively lower shear rates, and the viscosity difference became smaller as the shear rate was increased. The viscosity of the NR/NBR blend compounds was strongly affected by the addition of TOR but the effect became negligible with increasing the shear rate. Both the die‐swell ratio and the surface topology of extrudates were also affected by TOR addition; the dependence on shear rate was much stronger for higher TOR level. The NR/NBR blend compound showed much higher green tensile strength and elongation at break than those of the constituent components. Both the green tensile modulus and strength of the NR/NBR blend compound were greatly enhanced, while the elongation at break was reduced with the addition of TOR. © 2002 Society of Chemical Industry     

Improved mechanical properties of NR/EPDM blends by controlling the migration of curative and filler via reactive processing technique

Simple blending of natural rubber/ethylene–propylene–diene rubber (NR/EPDM) generally results in inferior mechanical properties because of curative migration and their differences for filler affinity. In this work, the 70/30 and 50/50 NR/EPDM blends prepared by reactive processing techniques were investigated and compared with the simple, nonreactive blends. The reactive blend compounds were prepared by preheating EPDM, containing all curatives to a predetermined time related to their scorch time prior to blending with NR. For the 70/30 gum blends, four types of accelerators were studied: 2,2‐mercaptobenzothiazole (MBT), 2,2‐dithiobis‐ (benzothiazole) (MBTS), N‐cyclohexyl‐2‐benzothiazolesulfenamide (CBS), and N‐tert‐butyl‐2‐benzothiazolesulfenamide (TBBS). When compared with the simple blends, the reactive blends cured with CBS and MBTS showed a clearly improved tensile strength whereas the increase of tensile strength in the blends cured with TBBS and MBT was marginal. However, a dramatic improvement of ultimate tensile properties in the reactive 50/50 NR/EPDM blends cured with TBBS was observed when compared with the simple blend. For the N‐550‐filled blends at the blend ratios of 70/30 and 50/50, the reactive‐filled blends prepared under the optimized preheating times demonstrated superior tensile strength and elongation at break over the simple blends. The improved crosslink and/or filler distribution between the two rubber phases in the reactive blends accounts for such improvement in their mechanical properties. This is shown in the scanning electron micrographs of the tensile fractured surfaces of the reactive blends, which indicate a more homogeneous blend. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

丁腈橡胶与三元乙丙橡胶共混研究

研究了共混比、增容剂用量、混炼方法对NBR/EPDM共混物性能的影响。试验表明,EP-DM可以提高NBR的耐老化性、电绝缘性,增容剂的加入可使共混物的力学性能提高。用量为10份时力学性能达到最佳,但不宜过量。经过各自配比后再混合胶料的方法,即母炼法,所得胶料的综合性能比普通方法要好。     

Swelling behavior of NR/EPDM rubber blends under compression strain

The effect of different blend compositions of natural rubber (NR)/ethylene–propylene diene monomer rubber (EPDM) on the swelling behavior of that blend in motor oil under compression strain was investigated. The compression recovery of all blend ratios investigated had positive values at low applied compression values (3%). However, at high compression values (18 and 35%), the compression recovery had negative values. The lower weight uptake of motor oil was shown by the EPDM vulcanizate, whereas the 25/75 NR/EPDM blend showed the highest compression recovery. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 3052–3057, 2001     

Rheological properties and compatibility of NR/EPDM and NR/brominated EPDM blends

Ethylene–propylene–diene terpolymer (EPDM) was modified by bromination reaction. Blending the resulting brominated EPDM with natural rubber (STR5L) and blending the unmodified EPDM with STR5L at various compositions were carried out. The rheological properties of the blends were investigated using a capillary extrusion. Shear flow curves of the pure rubbers and their blends illustrated the pseudoplastic property as shear thinning behavior with a power law index n < 1. True shear viscosity of all blends showed the negative deviation in relation to their additive values. Rheological behavior and two T_g's found from the DSC thermograms at all blend compositions indicated blend incompatibility for both sets of blends. The incompatibility of the vulcanized blends was also found by measuring the spin–spin relaxation time T₂ by pulsed NMR. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 837–847, 2003     

TPI/NR力学性能的分子动力学模拟

为研究杜仲胶(TPI)和天然橡胶(NR)之间的相容性、TPI/NR共混物的力学性能,采用分子动力学(MD)法在Compass力场条件下对其进行了模拟。研究结果表明:通过比较溶度参数差值(Δδ)的大小可预测TPI与NR之间的相容性,TPI/NR属于相容体系;与纯TPI相比,TPI/NR共混物的静态力学性能及动态拉伸抗疲劳性能更加优越。     

EPDM-g-MAH对EPDM/CPE共混性能的影响

为改善三元乙丙橡胶(EPDM)和氯化聚乙烯(CPE)的相容性,提高共硫化反应程度,采用氢化钠(NaH)/马来酸酐(MAH)体系,在橡胶加工设备中对EPDM进行改性反应,得到了改性的三元乙丙橡胶(EPDM-g-MAH)。研究了加入EPDM-g-MAH后EPDM/CPE共混胶的硫化特性、动态力学性能、加工性能和微观相态结构。结果表明,EPDM-g-MAH的加入,使EPDM/CPE共混胶相容性得到明显改善,胶料硫化速度加快,力学性能及动态力学性能得到提高。     

A study on the compatibility and physical properties of chlorinated polyethylene rubber/nitrile rubber blends

The miscibility and some physicomechanical characteristics of chlorinated polyethylene rubber (CPE) and nitrile rubber (NBR) blends have been investigated. Calculation of the heat of mixing, differential scanning calorimetry, and scanning electron microscopy analysis showed that CPE was miscible with NBR in all proportions. The cure and scorch times decreased with the increase in NBR content, whereas the maximum torque increased. The tensile strength, 100% modulus, elongation at break, tear strength, and compression set decreased with increasing of NBR content. After aging, hardness and tensile strength increased, and there was no drastic change in elongation at break on aging. The thermal aging resistance and the abrasion resistance of NBR are improved after blending with CPE, but the oil resistance decreased. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

原位聚合改性EPDM/NR并用胶的性能研究

通过原位聚合法对EPDM进行改性,并研究单体种类和用量对EPDM/NR并用胶物理性能的影响.结果表明,当甲基丙烯酸甲酯(MMA)单体用量(以EPDM质量为5 g计)为10 mL时,并用胶的撕裂强度和拉断伸长率达到最大值;当MMA用量增大到20mL时,并用胶的拉伸强度和邵尔A型硬度分别为9.66 MPa和90度,但拉断伸长率和撕裂强度明显下降.加入苯乙烯单体的EPDM/NR并用胶物理性能下降.     

EPDM/NR并用胶压缩永久变形的研究

研究了EPDM/NR并用比、配合剂、硫化体系、补强体系和EPDM预硫化工艺等对EPDM/NR并用胶高温条件下压缩永久变形的影响。结果表明,当EPDM用量介于70~80份之间时,并用胶压缩永久变形最大;EGDMA配合剂改性的EPDM/NR并用胶压缩永久变形最小,聚异丁烯改性的最大;过氧化物硫化体系的EPDM/NR并用胶压缩永久变形最小,硫黄硫化体系的最大;随炭黑类填料用量的增加,并用胶压缩永久变形先减小后增大,但随着无机类填料用量的增加而增加;填充快压出炭黑（N550）并采用EPDM预硫化工艺能有效降低并用胶压缩永久变形。     

Modified ethylene-propylene-diene elastomer (EPDM)-contained silicone rubber/ethylene-propylene-diene elastomer (EPDM) blends: Effect of composition and electron beam crosslinking on mechanical,heat shrinkability,electrical, and morphological properties

In this investigation, a gamma radiation-induced methacrylic acid (MAA)-grafted ethylene-propylene-diene elastomer (EPDM) was used as a third component (g-EPDM) in silicone rubber (SiR)/ethylene-propylene-diene elastomer (EPDM) blends. These blends were electron beam (EB) crosslinked. The effect of blend composition, the presence of g-EPDM, and EB crosslinking on the mechanical, heat shrinkability, electrical, and morphological properties of SiR/EPDM blends have been studied. To investigate the effect of grafted EPDM (g-EPDM), 10 wt % of g-EPDM was added to immiscible SiR/EPDM blends. Both silicone and EPDM are blended in different proportions (70:30 and 30:70) with and without g-EPDM followed by compression molding. To improve the properties and investigate the crosslinkability of binary and ternary blends further, the SiR/EPDM blends were irradiated by electron beam at different doses (50, 100, and 150 kGy). The gel content was found to increase with EPDM content, the presence of g-EPDM, and radiation dose. The addition of g-EPDM led to improvement of tensile properties (tensile strength, Young's modulus, percentage elongation, and toughness), electrical properties, and shrinkability of blends. EB crosslinking further enhanced the above properties. Surface morphology (SEM) revealed that the presence of g-EPDM and the incorporation of EB crosslinking improved the above properties of blends. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47787.     

Blending of NR/BR/EPDM by reactive processing for tire sidewall applications. I. Preparation,cure characteristics and mechanical properties

EPDM incorporated into blends of natural rubber/butadiene rubber (NR/BR) improves ozone resistance. In this work, the inferior mechanical properties of NR/BR/EPDM blends generally obtained by conventional straight mixing are overcome by utilizing a reactive processing technique. The entire amount of curatives, based on a commonly employed accelerator N‐cyclohexyl‐2‐benzothiazole sulfenamide (CBS) and sulfur, is first added into the EPDM phase. After a thermal pretreatment step tuned to the scorch time of the EPDM phase, the modified EPDM is mixed with premasticated NR/BR. The reactive blend vulcanizates show a significant improvement in tensile properties: tensile strength and elongation at break, as compared to those prepared by straight mixing, in both gum and carbon black‐filled blends. The increase of tensile properties in gum and filled reactive blend vulcanizates does suggest that the reactive processing technique leads to more homogeneous blends due to, either a better crosslink distribution, or more homogeneous filler distribution, or both. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103:2538–2546, 2007     

丁腈橡胶/三元乙丙橡胶并用胶的制备及性能

将丁腈橡胶(NBR)与三元乙丙橡胶(EPDM)并用,考察了生胶牌号、并用比、并用工艺对NBR/EPDM并用胶性能的影响,并对其耐臭氧及耐油性能进行了分析.结果表明,选用第三单体为亚乙基降冰片烯(即E型)的EPDM可以改善其与NBR的共硫化性能;当门尼黏度相近的NBR与EPDM的并用比(质量比)为70/30,且采用2种生胶先混炼,而后加入各种配合剂的制备工艺,并用胶具有良好的耐臭氧性能及物理机械性能;具有以NBR为连续相、EPDM为分散相结构形态的并用胶有较好的耐油性能与良好的耐臭氧性能.     

HNBR/EPDM共混物结构与性能研究

分别采用过氧化物和硫给予体作交联剂,考察了不同共混比对氢化丁腈橡胶（ＨＮＢＲ）／ＥＰＤＭ共混物性能的影响,并能力ＤＳＣ和ＴＥＭ分析了共混物的相容性,对两胶的共硫化也作了初步探讨。结果表明,两种硫化体系硫化的共混胶扯断伸长率保持率均在６０％以上,都具有优异的耐热氧老化性能。随ＨＮＢＲ用量增大,共混物的定伸应力、拉伸强度和撕裂强度均提高,磨耗明显降低。ＨＮＢＲ和ＥＰＤＭ为不相容体系,但硫化仪曲线显示二     

炭黑与NR/BR/EPDM共混胶混炼工艺研究

研究了混炼工艺对天然橡胶（NR）/顺丁橡胶（BR）/三元乙丙橡胶（EPDM）共混胶性能的影响。结果表明：炭黑预混入EPDM的混炼工艺可以改善NR/BR/EPDM共混胶的流动性,改善炭黑的分散程度,提高胶料的物理机械性能和耐屈挠疲劳性,预混入炭黑量以20%～50%（质量分数）较为合理;采取50%比例的硫化剂、促进剂、活性剂预混入EPDM的工艺方法能有效改善NR/BR/EPDM的共硫化性,显著提高胶料的物理机械性能和耐屈挠疲劳性。     

EPDM/NR共混橡胶的性能研究

采用硫黄硫化体系和过氧化物(硫化剂DCP)硫化体系对EPDM/NR并用胶实施复合交联,考察了不同共混比EPDM/NR共混胶的硫化特性、硫化胶的物理机械性能、耐水性及耐溶剂性能。结果表明:复合交联后,胶料的硫化特性、物理机械性能均有所提高;EPDM母炼胶中DCP的用量要高于NR;胶料共混比为80/20(EPDM/NR),其耐水性和耐溶剂性能达到最佳。     

硅橡胶/顺丁橡胶/乙丙橡胶共混材料的研究

针对硅橡胶具有较高耐热性．但力学性能差；三元乙丙橡胶（EPDM）力学性能较好，但互粘性较差；顺丁橡胶（BR）弹性好．但加工性能堇的特点，提出了将硅橡胶、三元乙丙橡胶与顺丁橡胶共混的方法，制成共混材料；再通过测定样品的性能，确定共混的最佳配比。结果表明：BR与EPDM、硅橡胶相客性较好，可达到共硫化；硅橡胶／BR／EPDM质量比为20／30／50时，共混物的物理机械性能和老化性能较好；用过氧化二异丙苯（DCP）／硫磺作硫化剂要好于用硫磺、过氧化二苯甲酰（BPO）和硫磺／BPO硫化剂。试样的耐热老化性能、邵尔A型硬度和扯断伸长率较好，其中样品的综合性能具备了硅橡胶、顺丁橡胶和三元乙丙橡胶的优点。