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Ethylene‐propylene‐diene monomer (EPDM) terpolymers were prepared using either vanadium (VOCl3/Al2Et3Cl3) or zirconocene (Et(Ind)2ZrCl2/MAO) catalyst systems. Residual metal contents in EPDM films were determined by Rutherford backscattering spectrometry. Metallocene catalyst systems exhibited a higher activity, producing EPDM with lower molecular weight and narrower molecular weight distribution. The highest activity guaranteed lower residual metal content (Zr/C = 10−5) than in the case of EPDM produced by VOCl3/Al2Et3Cl3 (V/C = 10−4). Subsequent steps of dissolution of the polymer and its reprecipitation were seen to reduce the metal contents in both metal systems. Concerning the cocatalyst retention, despite initial use of a very high amount of methylaluminoxane/metallocene (Al/Zr = 3000) in the reactor, only about 4% of this initial concentration remained in the polymer. On the other hand, in the case of vanadium‐based catalyst, almost all Al present in the initial conditions (≃8.3) remained in the polymer. In both cases, the residual Al/M ratio was close to the value generally proposed for the generation/stabilization of the active species. In the case of vanadium systems, a test in the synthesis of ethylene propylene rubbers indicated that the absence of diene in the polymer structure leads to a reduction in the residual vanadium content, indicating that the diene double bond might be responsible for partially vanadium coordination. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 1997–2003, 1999 相似文献
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Mnica Carcuchinski Haag Joo Henrique Zimnoch dos Santos Jairton Dupont Argimiro Resende Secchi 《应用聚合物科学杂志》1998,70(6):1173-1189
The development of a simplified kinetic model describing some effects observed in catalyzed olefin terpolymerization is presented. Based on the method of moments, the model describes the influence of Al/V ratio and diene concentration on reaction yield and on polymer characteristics such as molecular weight, ethylene incorporation, and polydispersity. In order to verify the model validity, the terpolymerization reactions were performed using VOCl3–Al2Et3Cl3 systems and 2-ethylidenebi-cyclo[2.2.1]hept-5-ene (ENB) as diene. The results of dynamic simulation fit well the experimental data for Al/V up to 15, but the model fails under high diene concentration, where branching reactions, neglected by reason of simplification, become significant. © 1998 John Wiley & Sons, Inc. J. Appl. Polym. Sci. 70: 1173–1189, 1998 相似文献
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Young-Soon Kim Joong-Hee Cho Gil-Sung Kim Gilson Khang Hyung-Shik Shin 《Electrochimica acta》2006,51(25):5445-5451
Copper electrochemical deposition on titanium with a ruthenium seed layer was investigated. The chemicals for the acid-bath ruthenium electrochemical deposition were ruthenium(III) chloride hydrate (RuCl3·3H2O), hydrochloric acid (HCl), sulfamic acid (NH2SO3H), and polyethylene glycol. The chemicals for the acid-bath copper electrochemical depositions were copper(II) sulfate hydrate (CuSO4·5H2O), sulfuric acid (H2SO4), and polyethylene glycol. Results were analyzed by field-emission scanning electron microscopy (FESEM), atomic force microscopy (AFM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and Rutherford backscattering spectrometry (RBS). Ruthenium thin film of ∼30 nm thickness, with equiaxial grains <10 nm, was deposited, on a blanket Ti with a root mean square roughness of 8.3 nm, at 2 V for 90 s. XPS and RBS analyses showed the presence of metallic Ru. The Ti substrate was found stable with respect to ECD of Ru but the Ru/Ti bilayer was not found stable in the Cu acid bath, resulting in the diffusion of Ti into Ru film. The depth profiling studies indicates that Ru film thickness ca. 1.4 nm and deposition time of 10 s can act as a good seed layer. 相似文献
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We report on the preparation and characterization of new polymeric ionomers based on EPDM with a high norbornene content. The sulfonation level is determined by means of X‐ray photoelectron spectroscopy and the microstructural characterization is obtained both through differential scanning calorimetry and dynamo‐mechanic analysis. In addition, the effects of certain plasticizers and polymers on the microstructure of these materials were studied, as well as their conducting properties, with special attention to this latter type of behavior, in view of the interest aroused by these materials as membranes in polymer fuel cells. From the obtained results, some of the synthesized membranes can be used for fuel cells because their high conductivity (≥10‐2 S/cm) and their good dimensional stability (any shrinkage observed). © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 3133–3141, 2001 相似文献
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在熔融状态下,利用Friedel-Crafts烷基化反应原位生成聚苯乙烯(PS)/EPDM共混物,考察路易斯酸品种、用量、混炼温度和混炼时间等对共混物性能的影响。结果表明,选择三氯化铝作为PS和EPDM大分子间形成接枝共聚物EPDM-g-PS的催化剂时效果较好;EPDM-g-PS的生成使PS/EPDM共混物的熔体质量流动速率和PS相的玻璃化温度下降,增大了PS和EPDM两相的界面结合力,从而提高了共混物的性能;当PS/EPDM共混比为60/40、三氯化铝用量为3份、混炼温度为140℃、混炼时间为5min时,共混物综合性能较好。 相似文献
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汽车向节能和低污染的方向发展使得EPDM汽车散热器胶管的工作环境发生了很大的变化,原来经常采用的硫黄硫化体系正逐步被过氧化物硫化体系所代替。列举了几个不同含胶率的典型过氧化物硫化体系散热器胶管配方以供参考。 相似文献
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可控长链支化EPDM的性能及应用 总被引:2,自引:2,他引:0
介绍可控长链支化(CLCB)EPDM的性能和应用.CLCB EPDM兼具窄相对分子质量分布和高长链支化度,炭黑分散性和抗炭黑焦烧性良好,抗坍塌性和耐压缩永久变形性能优异,挤出和硫化速度快.与门尼粘度和相对分子质量分布相当的传统EPDM相比,CLCB EPDM挤出性能优异,在密封条等挤出制品中应用具有很大潜力. 相似文献
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为了提高NBR抗臭氧解聚的稳定性,可以采用与EPDM并用的方法.文中叙述了在使用可保护大气臭氧层的硫磺硫化体系的条件下,利用高温处理来提高各种牌号EPDM与丁腈橡胶BHKC-28的相容性,从而改善其共硫化胶的力学性能和耐臭氧性.文章着重介绍了引入2,2,6,6-四甲基哌啶-1-氧基(TEMPO)自由基的作用,从而提高共... 相似文献
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试验研究纳米氧化锌/EPDM复合材料的物理性能和导热性能,并与炭黑和白炭黑补强的EPDM胶料进行对比.结果表明,纳米氧化锌的导热性能明显优于炭黑和白炭黑等传统补强填料,其对EPDM具有较好的补强作用,纳米氧化锌/EPDM复合材料的生热较低;采用偶联剂Si69对纳米氧化锌进行原位改性可以改善纳米氧化锌粒子与EPDM间的界面作用,提高其分散性,从而显著提高复合材料的物理性能,降低生热;改性纳米氧化锌/EPDM复合材料的物理性能和导热性能良好,可用于动态工况下使用的橡胶制品. 相似文献
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