丁腈橡胶非均相催化加氢研究进展

丁腈橡胶（NBR）选择性催化加氢是制备高附加值、高性能氢化丁腈橡胶（HNBR）的一个重要过程。将链段中C==C双键加氢饱和而保留氰基基团,不仅可保持其原有的耐油性和耐磨性,而且可极大地改善其耐侯性、耐臭氧性等。本文介绍了NBR加氢的几种工艺,着重综述了NBR非均相催化加氢的研究进展及发展方向,探讨了负载型催化剂的载体孔道结构和表面性质及活性组分组成对NBR加氢性能的影响。本文还对非均相催化加氢过程中的溶剂效应、催化剂的回收和循环再生进行了阐述,提出溶剂对催化加氢速率和加氢度都有重要影响,溶剂的受氢能力（β值）是影响加氢过程的关键参数。催化剂失活的主要原因是表面活性位点被聚合物覆盖,而利用有效的溶剂洗涤或者采用催化剂表面功能化的方式,可促使活性位再次暴露,恢复其加氢活性。最后,对非均相加氢制备高附加值HNBR体系中的催化剂设计、溶剂效应和催化剂再生等发展方向进行了展望。     

水溶剂化效应对CL-20分子结构的影响

CL-20是当前能量水平最高的新型含能材料,然而晶型复杂、感度高的问题使其应用受到限制。为了降低感度并使其转化为单一稳定且能量密度最高的ε晶型结构,常需要采用多种溶剂或反溶剂,进行结晶或共晶处理。除此以外,运输和储运过程中也需要溶剂进行保护。本文针对常见的水溶剂,采用Gaussian 09程序包,运用密度泛函理论,利用B3LYP/6-31g(d)基组,探讨水溶剂化效应对CL-20分子结构中的键长、键角、二面角、原子的自然电荷以及分子轨道的影响规律。     

丁腈橡胶催化加氢反应研究

氢化丁腈橡胶具有良好的耐油性和耐氧性,广泛应用于汽车和石油行业,通过丁腈橡胶溶液均相催化加氢制得,采用铑类和钯类均相催化剂。考察不同溶剂、催化剂及m(Ru)∶m(丁腈橡胶)对丁腈橡胶加氢的影响。采用红外光谱法和核磁法对氢化丁腈橡胶的结构进行分析,筛选出价廉、活性高和选择性高的催化剂。结果表明,在丁腈橡胶加氢反应中,丁酮可作为溶剂,Ru(PPh3)3Cl2催化剂具有高活性和高选择性。在丁酮200 m L、丁腈橡胶5 g、Ru(PPh3)3Cl2催化剂、m(Ru)∶m(丁腈橡胶)=0.000 20∶1、反应温度140℃、氢压8.0 MPa和反应时间4 h条件下,加氢度和选择性均达到100%,具有与Rh(PPh3)3Cl相当的催化性能。     

丁腈橡胶的催化加氢反应

以三(三苯基磷)氯化铑(简称Rh)为催化剂、氯苯为溶剂,在高压釜中对丁腈橡胶(NBR)进行加氢反应,制得了氢化丁腈橡胶(HNBR),考察了Rh/NBR(质量比)、胶液质量分数、氢气压力、反应温度和反应时间对加氢度的影响.结果表明,在Rh/NBR为150×10-6～200×10-6、胶液质量分数为4％ ～6％、氢气压力为...     

阻溶剂存在时硫酸钙的溶解速度研究

本文选用六偏磷酸钠为阻溶剂、研究了阻溶剂浓度、溶解温度、溶解时间、搅拌速度和硫酸钙粒度对硫酸钙溶解速度的影响。分别归纳出各种因素的影响规律，探明了阻溶剂存在时硫酸钙的溶解受扩散控制。一切增大扩散阻力的措施均可提高对硫酸钙的阻溶效果。     

在上升的溶剂流中，湖盐溶解过程的研究

在上升的溶剂流中，湖盐溶解过程的研究ＢａｃｅｐＭａＨ等盐湖的沉积盐是氨碱法纯碱生产、烧碱生产及食盐生产用氯化钠原料的潜在资源。生产这些产品时，首先应将原盐溶解于水，这时生成的粗盐水中氯化钠的含量即接近饱和状态。有一种使粒状盐溶解的设备被广泛采用，在该...     

微观结构对丁腈橡胶硫化胶物理性能的影响

研究橡胶基体及填料微观结构对丁腈橡胶(NBR)硫化胶物理性能的影响。结果表明:随着丙烯腈质量分数的增大,炭黑补强NBR硫化胶的拉伸强度先增大后减小,拉断伸长率减小,邵尔A型硬度和撕裂强度增大;随着生胶门尼粘度的增大,炭黑补强NBR硫化胶的邵尔A型硬度基本不变,定伸应力增大,拉伸强度和拉断伸长率减小;随着炭黑粒径的减小,硫化胶的定伸应力呈增大趋势,拉伸强度和撕裂强度增大,高定伸下炭黑粒径对应力的贡献较大;随着炭黑结构度的提高,硫化胶定伸应力增大,拉伸强度和撕裂强度减小。     

溶剂化效应对金属-有机骨架材料界面微环境催化性能的影响

金属-有机骨架材料(metal-organic frameworks,MOFs)的纳微结构可根据特定需求进行功能化调控,有望成为良好的工业催化材料。由于溶剂环境可对其界面微环境及催化性能产生较大影响,因此研究溶剂化效应对于MOF材料的影响具有重要的意义。以Cu-BTC和MOP-15两种典型MOF材料作为研究对象,采用密度泛函理论与COSMO溶剂模型相结合的方法,考察了溶剂效应对材料几何结构与电子稳定性的影响,并研究了不同溶剂对其Lewis酸性的影响。结果表明,溶剂环境可以使材料中的电子从不饱和配位金属处转移到有机配体上,进而使材料具有更强的Lewis酸性,并且电负性较大有机配体构成的MOF材料,受溶剂效应的影响更加显著。本工作将有助于深入理解溶剂化对调控MOF材料液相催化活性的影响。     

溶剂对间二硝基苯催化加氢制间苯二胺反应过程的影响

研究了溶剂苯和乙醇对间二硝基苯加氢制间苯二胺的反应过程的影响. 结果表明,中间产物在溶剂中的溶解度对反应选择性有重要影响,间亚硝基硝基苯在苯中含量远小于乙醇. 2 MPa下,随反应温度从50℃升至90℃,反应时间苯溶剂中从350 min减少至75 min,乙醇溶剂中从120 min减少至35 min. 80℃下,随氢压从0.4 MPa升至2.8 MPa,反应时间苯溶剂中从250 min减少至85 min,乙醇中从70 min减少至40 min. 有机物和氢气在溶剂中的溶解度及由溶剂效应引起的催化剂表面的吸脱附行为对反应速率有较大影响.     

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。     

丁腈橡胶非均相加氢催化剂失活原因及再生性能研究

对丁腈橡胶非均相催化加氢制备高附加值氢化丁腈橡胶过程中催化剂失活的原因进行了探究,发现造成催化剂活性下降的原因并不是贵金属纳米颗粒的流失、团聚或中毒,而是催化剂表面的活性位被聚合物覆盖而无法与反应物接触,因此将覆盖在活性位上的聚合物进行脱除才是催化剂再生和重复利用的关键。根据相似相容原理选择单溶剂或者混合溶剂对反应后催化剂进行处理,结果表明经过乙酸乙酯、丁酮、N,N-二甲基甲酰胺以及N-甲基吡咯烷酮这四种有机溶剂处理后,其催化加氢活性可以恢复至新鲜催化剂活性的90%;当用混合溶剂处理后,其催化活性可以提高至新鲜催化剂活性的95%,且循环利用4次其催化活性仍能保持不变。     

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。     

Effect of cyanide content on the tribological performance of nitrile butadiene rubber

Nitrile butadiene rubber (NBR) has received a lot of attention as a sealing material, and its tribological performance is a crucial factor in determining the efficiency with which it will operate under various operating situations. In this study, NBR specimens with varying degrees of cyanide content, namely low cyanide (DN401), medium cyanide (DN2850), medium-high cyanide (DN3380), and high cyanide (DN4050), were selected to investigate their tribological behavior when subjected to NO.10 aviation oil. To emulate their frictional responses during startup and shutdown operations, all four types of NBR were assessed under dry conditions. As the cyanide content increased, the coefficient of friction (COF) dropped from 1.381 to 0.810 and wear rate dropped from 2.38 × 10⁻³ mm³/(N m) to 1.88 × 10⁻⁴ mm³/(N m). When employed in conjunction with NO.10 aviation oil, DN401 and DN3380 exhibited COFs of 0.0963 and a slightly higher value of 0.127, respectively. Following aging treatment at 80°C in NO.10 aviation oil, stress reduction reached 65.8%, indicating the poorest performance among the four variants of NBR. Considering the COF, wear rate, and aging performance, DN3380 emerges as the most favorable choice for practical applications, thereby offering valuable insights into the selection of nitrile rubber for sealing materials.     

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.     

HNBR补强填充体系的研究

研究了白炭黑及改性酚醛树脂（SP6701）对氢化丁腈橡胶（HNBR）补强效果的影响。结果表明,在N550用量不变的情况下,白炭黑的加入能显著提高HNBR硫化胶的定伸应力和硬度,改善HNBR的耐热空气老化性能;加入SP6701后,胶料的拉伸强度逐渐降低,拉断伸长率先降低后升高,硬度和定伸应力则显著增大,混炼胶的Payne效应则是随着SP6701含量的增加而增强。综合而言,SP6701能够明显提高硫化胶的硬度和定伸应力,但对于其它性能的影响很微弱,甚至会产生相反的影响。     

High‐performance hydrogenated nitrile butadiene rubber composites by in situ interfacial design of nanoclays

Considering industrial requests, it has become a hot issue to prepare advanced rubber composites with high strength and great toughness. Despite enhanced strength and stiffness, rubber composites suffer markedly reduced extensibility and toughness. Herein, a novel interfacial strategy is proposed to fabricate amine‐modified montmorillonite (MMT)/hydrogenated nitrile butadiene rubber composites by designing in situ ionic bond interfaces. The well‐distributed interfaces, which are composed of protonated amine groups on the MMT surfaces and electronegative methacrylic acid (MA), were constructed by adding a slurry with a small amount of MMT and MA to rubber. After the vulcanization, self‐polymerization of MA developed nanoparticles and grafting structures onto rubber chains to bond MMT by strong ion attractions. Although the crosslinking degree of rubber was reduced, the dispersion of MMT and its interfacial interactions with rubber were improved remarkably, as demonstrated by morphology observations, dynamic mechanical analysis and infrared spectra. As a result, the strength, modulus, elongation, toughness and gas barrier properties of the rubber composites were simultaneously strikingly improved relative to composites without MA modifiers. We believe that this work provides a promising methodology of fabricating high‐performance rubber composites. © 2019 Society of Chemical Industry