Characteristics of ethylene propylene diene monomer rubber/organoclay nanocomposites resulting from different processing conditions and formulations

Several parameters which affect the nanocomposite formation in a sulfur‐cured ethylene propylene diene rubber (EPDM) containing 10 phr organoclay (montmorillonite modified with octadecylamine; MMT–ODA), were investigated. The parameters varied were linked to processing (mixer type, temperature) and rubber recipe (compatibilizer, accelerator). Increasing temperature and high shear mixing (internal mixer instead of open mill) improved the mechanical performance of the rubber nanocomposites. A more pronounced effect was achieved by using polar EPDM rubbers (maleic anhydride and glycidyl methacrylate grafted version) as compatibilizer. Among the accelerators, zinc diethyldithiocarbamate proved to be most suitable. The microstructure of the rubber/organoclay systems was studied by X‐ray diffraction, transmission electron microscopy and scanning electron microscopy. Organoclay intercalation/exfoliation was accompanied by its more or less severe confinement (reaggregation, deintercalation). This was traced to a partial or full removal of the ODA intercalant from the clay galleries via the formation of a zinc complex in which amine groups of the ODA and sulfur participated. Copyright © 2004 Society of Chemical Industry     

三元乙丙橡胶/聚丙烯动态硫化热塑性弹性体的相态结构

用扫描电镜研究了三元乙丙橡胶(EPDM)聚/丙烯(PP)动态硫化热塑性弹性体(TPV)相态结构的形成过程,探讨了交联密度、制备工艺、螺杆转速对EPDM/PP TPV相态结构的影响。结果表明,采用以酚醛树脂为硫化剂的动态硫化工艺制备的EPDM/PP TPV,其相态结构实现了由EPDM和PP组成的双连续相到以EPDM为分散相、PP为连续相的转变;当硫化剂用量为7份时,橡胶相硫化速率和交联密度最大;当螺杆转速为180 r/m in时,反应性挤出工艺较之密炼机工艺制备的EPDM/PP TPV的橡胶粒子更细小、分散更均匀。     

不同牌号三元乙丙橡胶的结构与性能对比

对8个牌号三元乙丙橡胶(EPDM)的微观结构、硫化特性、物理机械性能、耐磨性能及耐老化性能进行了对比.结果表明,EPDM中第3单体亚乙烯基降冰片烯(ENB)质量分数影响了EPDM的硫化速率.8个牌号中EPDM 9950 C的硫化速率最快,EPDM 3722的硫化速率最慢;充油胶EPDM 3666的硫化速率与结构类似的E...     

三元乙丙橡胶硫化胶力学性能及动静刚度比

研究了硫化剂用量、填充增强剂的种类及用量以及发泡倍率等对三元乙丙橡胶硫化胶力学性能及动静刚度比的影响。结果表明,动静刚度比随着橡胶交联密度的增加、填料增强作用的减弱、填料用量的减少以及发泡倍率的增大而逐渐减小。     

Study on the morphology,static and dynamic mechanical properties of (styrene butadiene rubber/ethylene propylene diene monomer/organoclay) nanocomposites vulcanized by the gamma radiation

Blends of styrene‐butadiene rubber/ethylene–propylene‐diene monomer (SBR/EPDM) with and without organoclay (OC) were prepared by melt mixing method. Then the samples were vulcanized by gamma radiation in comparison to conventional sulfur curing system. Characterization by X‐ray diffraction analysis, atomic force microscopy, and Field emission scanning electron microscopy revealed the intercalation structure and good dispersion of the OC in prepared nanocomposites. In addition to this, by increasing the absorbed dose of radiation and using OC, reduction in solvent uptake, increase in crosslink density and improvement of mechanical and dynamic–mechanical properties were observed. Comparison of the tensile strength of irradiated nanocomposite with the sulfur cured one's displayed the synergistic effect of the OC and gamma radiation on tensile properties of SBR/EPDM blend. Mooney–Rivlin plot confirmed the increase in crosslink density and interaction between rubbers due to presence of OC and increasing absorbed dose. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43581.     

用于变压器的丁腈橡胶/三元乙丙橡胶并用胶

为了实现丁腈橡胶(NBR)与三元乙丙橡胶(EPDM)并用作为变压器密封材料,研究了并用比、增容剂及硫化体系种类对NBR/EPDM并用胶的影响。结果表明,NBR/EPDM(质量比)为70/30时并用胶具有良好的耐臭氧性能与最佳的综合物理机械性能;在并用胶中加入增容剂乙华平8784可以改善其物理机械性能;使用过氧化物硫化体系硫化并用胶的物理机械性能比使用硫黄/促进剂硫化体系者更好。     

硅酸盐纳米短纤维增强三元乙丙橡胶复合材料的结构与性能

用硅烷偶联剂改性针状硅酸盐(FS)与三元乙丙橡胶(EPDM)机械共混,制备了EPDM/改性FS复合材料,研究了FS在EPDM中的分散性,考察了偶联剂和改性FS用量、FS所含自由水对复合材料力学性能和各向异性的影响.结果表明,经过偶联荆改性的FS能够解离成纳米纤维均匀分散于EPDM中,每100份FS的偶联刺最佳用量为24份;EPDM/改性FS复舍材料具有短纤维增强橡胶复合材料的应力-应变特征和力学性能的各向异性,且随改性FS和偶联剂的用量增加,这种力学行为更加明显;FS中所舍自由水对复合材料的常温和高温拉伸性能有明显影响.     

乙丙橡胶生产工艺与技术

乙丙橡胶以其独特的性能,在汽车工业、建筑行业、油品添加剂、塑胶跑道等领域有广泛的应用。本文主要介绍了乙丙橡胶生产技术、乙丙橡胶产品牌号、性能以及应用领域,结合现有的乙丙橡胶科研情况,阐述了乙丙橡胶催化剂的研发、核壳型球状乙丙橡胶、原位聚合法合成长链支化乙丙橡胶、乙烯、丙烯与其他二烯烃的共聚物研究进展;详细研究了乙丙橡胶溶液聚合工艺技术中的聚合技术、单体回收技术、失活洗涤技术、闪蒸提浓技术以及国外公司在中国建设装置的生产技术情况。提出了乙丙橡胶的关键生产技术是乙丙橡胶聚合所采用的催化剂体系,通过催化体系的更新换代,开发不同用途的乙丙橡胶,以满足开发高性能材料的要求。在此基础上,指出了今后乙丙橡胶新的催化体系开发将成为未来的研究重点。     

阻燃三元乙丙橡胶研究进展

综述了近10年国内外三元乙丙橡胶(EPDM)及其复合材料的阻燃研究状况,对卤系、金属氢氧化物型、磷系、硅系、膨胀型等阻燃体系分别进行了列表总结和分类讨论。卤系阻燃体系主要论述了常用的十溴二苯醚和十溴二苯乙烷及其协效阻燃体系;金属氢氧化物体系论述了氢氧化镁和氢氧化铝及其协效体系;磷系阻燃体系论述了微胶囊红磷、聚磷酸铵等;硅系阻燃体系论述了蒙脱土、纳米二氧化硅(SiO2)和有机硅氧烷等;膨胀阻燃体系论述了聚磷酸铵/季戊四醇/三聚氰胺(APP/PER/MEL)等阻燃体系。     

交替层状结构氯化丁基橡胶/三元乙丙橡胶复合材料的阻尼性能

采用多层共挤技术制备了具有交替层状结构的氯化丁基橡胶(CIIR)/三元乙丙橡胶(EPDM)复合材料,并与常规共混法cIIR/EPDM复合材料的阻尼性能进行了比较.结果表明,交替层状复合材料具有双连续相结构;与共混复合材料相比,交替层状结构复合材料的损耗因子和有效阻尼范围增大,且随着其层数的增加,损耗因子和有效阻尼范围、储能模量和损耗模量均增大;室温下层数较多的CIIR/EPDM复合材料在100～110 Hz的阻尼性能更优异.     

Comprehensively improved mechanical properties of silane crosslinked polypropylene/ethylene propylene diene monomer elastomer blends

The properties and structure of silane crosslinked polypropylene (PP)/ethylene propylene diene monomer (EPDM) elastomer blends had been carried out. Fourier transform infrared spectroscopy and gel content tests were employed to evaluate the crosslinking reaction of PP/EPDM blends. Crosslinking efficiency of PP/EPDM blends was investigated using thermogravimetric analysis, differential scanning calorimeter, dynamic mechanical analysis, dynamic rheology, and tensile testing. Tanδ curves of silane crosslinked PP/EPDM blends exhibited an obvious “gel point” originated from the formation of dynamic crosslinking network. The blend corresponding to the “gel point” presented comprehensively improved mechanical properties. These results demonstrated that characteristic rheological parameters showed close correlations with key mechanical properties of silane crosslinked PP/EPDM blends. Scanning electron microscopy images illustrated that crosslinking had remarkably changed the morphologies of PP/EPDM blends. The large deformation mechanism of these blends had been suggested.     

Optimization of hybrid oil/water-swelling ethylene/propylene/diene monomer compounds

Hybrid swell packers are rubber products capable of swelling in (saline) water and hydrocarbon oils, by exploiting the hydrocarbon diffusion properties of an nonpolar elastomer with the osmotic swelling of a water absorbent (WA). In this study, a variety of modified natural and synthetic WAs and mixtures thereof have been screened in a rubber compound with respect to swelling in decalin, demineralized, and saline water, respectively. We aimed at achieving high and fast swelling in all used media. Mixing of the various WAs in an ethylene/propylene/diene monomer (EPDM)/carbon black masterbatch at an addition level of 75 phr did not pose any problems, although it was found that the WAs did affect the sulfur vulcanization. Decalin swelling of the vulcanizates is very fast, reaching high equilibrium swelling within 1.5 days. Swelling in demineralized or saline water is much slower, with up to 300% swelling in water and up to 100% swelling in saline water. Significant leaching of the organic WA from the EPDM vulcanizates to the water phase occurs. Some combinations of WAs show synergetic effects for swelling in water. To our knowledge, such a systematic study of hybrid swelling elastomers constitutes a novelty in the open literature.     

Dynamically vulcanized polypropylene/ethylene‐propylene diene monomer/organoclay nanocomposites: Effect of mixing sequence on structural,rheological, and mechanical properties

Dynamically vulcanized thermoplastic elastomer (TPE) nanocomposites based on polypropylene (PP), ethylene‐propylene diene monomer (EPDM) and cloisite 15A were prepared via direct melt mixing in a co‐rotating twin‐screw extruder. The mixing process was carried out with optimized processing parameters (barrel temperature = 180°C; screw speed = 150 rpm; and feeding rate = 0.2 kg/hr). The formulation used to prepare the nanocomposites was fixed to 75/20/5 (PP/EPDM/Cloisite^©15A), expressed in mass fraction. Effect of mixing sequence on the properties of vulcanized and unvulcanized (TPE) nanocomposites prepared under similar conditions was investigated using X‐ray diffraction (XRD) and a tensile testing machine. Results showed that the sequence of mixing does affect the properties of final TPE nanocomposites. Accordingly, nanocomposite samples prepared through mixing the preblended PP/clay masterbatch with EPDM phase, show better clay dispersion within the polymer matrix. J. VINYL ADDIT. TECHNOL., 22:320–325, 2016. © 2014 Society of Plastics Engineers     

超细全硫化粉末丁苯橡胶/三元乙丙橡胶共混物的结构与性能

制备了超细全硫化粉末丁苯橡胶(UFPSBR)/三元乙丙橡胶(EPDM)共混物,研究了其硫化特性、相态结构、动态力学性能及物理机械性能。透射电镜观察表明,无论UFPSBR与EPDM共混比如何,UFPSBR粒子始终保持为分散相。当UFPSBR用量为10份(质量)时,它在EPDM中的分散相尺寸为200 nm左右;用量较高时其分散相尺寸较大,存在大量的聚集体。动态力学分析结果显示共混物存在2个玻璃化转变温度,说明共混物存在两相结构。加工性能分析结果表明,UFPSBR粒子在EPDM基质中形成了网络结构,对EPDM基质起到了较好的增强作用,当UFPSBR与EPDM的质量共混比为50/50时,共混物的拉伸强度可达13.4 MPa。UFPSBR对EPDM的硫化特性有明显影响。     

用熔体流动指数仪研究三元乙丙橡胶熔体的流变性能

用熔体流动指数仪研究了三元乙丙橡胶(EPDM)熔体的流变性能,建立了实验条件下EPDM的熔体流动指数(MFI)与流变参数、门尼黏度之间的关系。结果表明,EPDM 70的非牛顿指数和活化能比EPDM 80的大,2种橡胶熔体的剪切速率与MFI成线性关系,剪切黏度与MFI成乘幂关系。     

氯化聚乙烯用量对三元乙丙橡胶/尼龙共混胶性能的影响

研究了增容剂氯化聚乙烯（CPE）的用量对三元乙丙橡胶/尼龙（EPDM/PA）硫化胶热空气老化前后和用非极性油处理后力学性能及耐磨性能、耐油性能的影响。结果表明,随着CPE用量的增大,EPDM/PA硫化胶热空气老化后拉伸强度和100%定伸应力呈上升趋势,扯断伸长率和永久变形均缓慢下降,邵尔A硬度保持不变。用非极性油处理后EPDM/PA硫化胶的拉伸强度和扯断伸长率随CPE用量的增大呈上升趋势,100%定伸应力基本不变。CPE的加入对硫化胶的拉伸强度、撕裂强度、扯断伸长率等性能有一定的提高,说明EPDM和PA两相的相容性改善,在用量为6份时硫化胶的力学性能较佳。随着CPE用量的增大,DIN磨耗呈下降趋势,耐磨性能提高;质量变化率和体积变化率略有降低,耐油性能有所提高。     

Thermal and mechanical properties of dough modeling compound reinforced ethylene propylene diene monomer/silicon rubber composites

Ethylene propylene diene monomer (EPDM)/silicon rubber composite was prepared by adding dough‐modeling compound (DMC). EPDM/silicon rubber is the matrix of the composite, and DMC is a disperse phase (reinforced phase). The morphology of the composite was studied by scanning electron microscopy, and it was found that the compatibility of DMC/EPDM/silicon rubber composite was good. The influence of the DMC and peroxide curing agents on the mechanical and thermal properties were studied. The results showed that the mechanical and thermal properties of the composite were best, when DMC/EPDM/silicon rubber was 80/25/75. The thermal properties of the composite prepared with added equivalent dicumyl peroxide was better than those with added benzoperoxide, but Shore A hardness and elongation at break are unchangeable. The integral properties of DMC reinforced EPDM/silicon rubber composite was much better than three raw materials. POLYM. COMPOS. 27:621–626, 2006. © 2006 Society of Plastics Engineers     

Effects of fillers,maleated ethylene propylene diene diene rubber,and maleated ethylene octene copolymer on phase morphology and oil resistance in natural rubber/nitrile rubber blends

The phase morphology and oil resistance of 20/80 NR/NBR blends filled with different types of fillers and copolymers were investigated. In the case of filler effect, N220, N330, and N660 carbon blacks with different particle sizes were used. Additionally, the blends filled with nonblack‐reinforcing fillers, that is, precipitated and silane‐treated silica, were investigated. To study the compatibilization effect, maleated ethylene propylene diene rubber (EPDM‐g‐MA) and maleated ethylene octene copolymer (EOR‐g‐MA) were added to the blends. The results revealed that the addition of filler, either carbon black or silica, to the blend caused a drastic decrease in NR dispersed phase size. Carbon blacks with different particle sizes did not produce any significant difference in NR dispersed phase size under the optical microscope. Silica‐filled blends showed lower resistance to oil than did the carbon black–filled blends. In addition, it was determined that neither EOR‐g‐MA nor EPDM‐g‐MA could act as a compatibilizer for the blend system studied. The oil resistance of the blends with EPDM‐g‐MA is strongly affected by the overall polarity of the blend. In the case of EOR‐g‐MA, the oil resistance of the blends is significantly governed by both overall polarity of the blend and phase morphology. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1156–1162, 2003     

动态硫化法制备三元乙丙橡胶/聚酰胺热塑性弹性体

采用动态硫化技术制备了三元乙丙橡胶(EPDM)／聚酰胺(PA)热塑性弹性体,研究了增容剂种类及用量、硫化体系及其用量、加料顺序、PA用量对其性能的影响,用扫描电镜分析了其相态结构。结果表明,用13份(质量份,下同)的氯化聚乙烯作为增容剂时,对该共混体系的增容效果最好;硫黄硫化体系是EPDM／PA热塑性弹性体的最佳硫化剂,当硫黄用量为2份时,既保证了该热塑性弹性体中的橡胶相能充分交联,又可避免过硫化对产品性能造成的负面影响;PA用量为35份的EPDM／PA热塑性弹性体具有良好的力学性能、耐溶剂性能和耐热老化性能;EPDM以平均粒径为2～5μm的粒子形态均匀分布于PA连续相中。     

Morphological evolution and properties of thermoplastic vulcanizate/organoclay nanocomposites

Nanocomposites composed of organoclay and thermoplastic vulcanizates (TPVs) based on uncompatibilized or compatibilized polypropylene (PP)/ethylene–propylene–diene rubber (EPDM) blends were prepared in this study. The morphology of the nanocomposites was studied with wide‐angle X‐ray diffraction and transmission electron microscopy, which suggested that the addition of the compatibilizer played a key role in determining the morphology of the composites because of their interaction with the clay surface. Scanning electron microscopy study indicated the changes in the morphology of the rubber particles. Dynamic mechanical analysis was also applied to the analysis of these phenomena. Moreover, for nanocomposites with uncompatibilized PP/EPDM blends as the matrix, the samples showed tensile enhancement compared with neat TPV. Although the addition of the compatibilizer changed tensile properties of the composites in a rather different trend, the tensile modulus increased dramatically when the compatibilizer was added. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40618.