端羧基液体丁腈橡胶的合成

详细研究了端羧液体丁腈橡胶合成过程中的条件控制，确定了以过氧化戊二酸为引发剂、乙酸为溶剂的反应体系，收率达６５％以上，且重复性较好。     

羧基丁腈橡胶合成过程中凝胶生成的主要影响因素

研究了羧基丁腈橡胶合成过程中凝胶形成的因素,考察了相对分子质量调节剂叔十二碳硫醇、聚合温度、反应速率及最终的转化率对凝胶形成的影响规律。结果表明,相对分子质量调节剂的用量对凝胶生成的控制起重要作用,在其他条件不变的情况下,叔十二碳硫醇用量越大则凝胶含量越低; 聚合温度太低或过高都会使凝胶含量增加,于5~8℃下聚合时的凝胶含量较低; 将聚合的反应速率控制在4~5%/h时产生的凝胶相对较少,太快或太慢都易使凝胶生成; 凝胶含量随转化率的升高而逐渐增大,转化率达到一临界值后凝胶含量随转化率的继续增加而急剧上升。     

羧基丁腈橡胶的硫化性能

用无硫硫化体系、低硫高促进剂硫化体系、普通硫黄硫化体系、过氧化物硫化体系、金属氧化物硫化体系和硫黄／金属氧化物硫化体系对羧基丁腈橡胶（XNBR）进行了硫化,研究了XNBR的硫化性能、物理机械性能、耐老化性能、压缩永久变形和耐油性能。结果表明,采用普通硫黄硫化体系、硫黄／金属氧化物硫化体系所得到的XNBR硫化胶的综合物理机械性能较好;用无硫硫化体系、低硫高促进剂硫化体系和硫黄／金属氧化物硫化体系所得到的XNBR硫化胶的耐老化性能较好;用硫黄／金属氧化物硫化体系所得到的XNBR硫化胶的耐磨性、压缩永久变形较好;用普通硫黄硫化体系和硫黄／金属氧化物硫化体系所得到的XNBR硫化胶的耐油性能较好。     

羧基丁腈橡胶与炭黑的结合对低应变动态性能的作用

低应变动态机械性能揭示了羧基丁腈橡胶在190℃高温下模压时同表面已氧化的炭黑所产生的物理—化学相互作用。作用程度取决于填料表面含氧官能团浓度以及模压时间和温度。倘若硫黄硫化体系在150℃较低的温度下模压,会使橡胶和填料之间化学作用降低。     

羧基丁腈橡胶的性能研究

研究羧基丁腈橡胶 (XNBR)的硫化特性和物理性能。结果表明 ,高羧基丁腈橡胶具有硬度、拉伸强度和定伸应力高 ,耐磨性好 ,压缩永久变形大 ,加工安全性较差等特点 ;低羧基丁腈橡胶的物理性能与NBR接近 ,加工安全性好 ;硬脂酸不是高羧基丁腈橡胶的有效防焦剂 ;白炭黑对XNBR的共价交联有延迟作用。     

丁腈橡胶臭氧化制备羧基丁腈橡胶

以臭氧氧化丁腈橡胶合成了羧基丁腈橡胶,研究了反应时间、反应温度、臭氧通入量及丁腈橡胶胶液质量浓度对产物特性黏数和酸值的影响.结果表明,以丁腈橡胶臭氧化制备羧基丁腈橡胶,在实验范围内,反应温度升高、增大臭氧通入量和降低丁腈橡胶胶液质量浓度可以提高羧基丁腈橡胶的羧基含量,降低丁腈橡胶的相对分子质量.但是反应时间的影响较为复...     

白炭黑与羧基丁腈橡胶的结合

研究了混炼过程中羧基丁腈橡胶（XNBR）与白炭黑的化学结合对补强作用的影响。试验结果表明，低温（70℃）下白炭黑填充XNBR胶料的流变曲线有3个转矩峰；高温（150和170℃）混炼时白炭黑填充XNBR胶料的流变曲线比白炭黑填充NBR胶料多一个转矩峰。红外光谱分析表明，XNBR分子中的－COOH与白炭黑的－OH发生了酯化反应。填充沉淀法白炭黑的XNBR硫化胶的综合力学性能优于填充气相法白炭黑的硫化胶。     

PolymerLatex羧基丁腈橡胶将扩能

德国Polymer Latex公司最近宣布，为满足手套浸渍产业需求，将在意大利和马西来亚扩增羧基丁腈橡胶（X-NBR）年产能12万吨。     

羧基丁腈橡胶改性酚醛树脂的研究

以羧基丁腈橡胶和苯酚为原料,通过F-C烷基化反应,再与甲醛聚合制得羧基丁腈橡胶改性的酚醛树脂,并对工艺进行优化.结果表明,最优工艺条件为:甲醛和苯酚的摩尔比(F/P)为0.80,羧基丁腈橡胶用量为苯酚用量的2.5％,以氢氟酸为催化剂,催化剂用量为苯酚用量的0.30％,F-C烷基化反应温度为120℃,反应时间为6 h.所...     

Ionic elastomers based on carboxylated nitrile rubber and magnesium oxide

The crosslinking of carboxylated nitrile rubber (XNBR) with magnesium oxide (MgO) leads to an ionic elastomer with thermoplastic nature and better physical properties than the ones obtained with other metallic oxides. The crosslinking reaction leads to the formation of a metallic salt as unique product, as it could be seen on the ATR analysis of the samples, prepared at different reaction times. The mechanical properties of the material increase with the amount of crosslinking agent and segregation of an ionic microphase takes place. The presence of this microphase is demonstrated by a relaxation at high temperatures. The apparent activation energy of this relaxation is smaller than the activation energy of the glass transition of the elastomer, the former being more dependent on the amount of metallic oxide than is the latter. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 1894–1899, 2007     

Vulcanization of carboxylated nitrile rubber (XNBR) by zinc peroxide

The vulcanization of carboxylated nitrile rubber (XNBR) with zinc peroxide, which produces ionic crosslinks, has been studied in relation to vulcanization time. Vulcanized compounds present two transitions, corresponding to the glass transition of the polymer at low temperatures and the ionic transition resulting from the formation of ionic aggregates. Both transitions are displaced to higher temperatures with increasing crosslink density. The ionic associations which give rise to high values of mechanical properties disappear on exposure of the vulcanized compounds to saturated ammonia vapour. This treatment produces a decreased crosslink density resulting in the disappearance of the ionic transition. When the action of ammonia is terminated by immersion in solvent followed by drying, the original crosslink density is recovered and the ionic transition reappears, although at higher temperatures. However, with increasing crosslink density, the difference between the temperatures at which both transitions take place diminishes. All these factors can be interpreted as reflecting the generation of a new and more compatible arrangement of the newly-appearing ionic clusters. © 1999 Society of Chemical Industry     

Ionic elastomer blends of zinc salts of maleated natural rubber and carboxylated nitrile rubber: Effect of grafted maleic anhydride

Zinc neutralized maleated natural rubbers (Zn‐MNR) were prepared by solution grafting and neutralization with zinc acetate in one‐step. It was later used for blending with carboxylated nitrile rubber (XNBR) in the composition of 50/50 parts by weight. The effect of grafted anhydride content (1.2, 1.6, 2.0, and 2.5% wt of NR) on the tensile properties of ionic rubber blends (Zn‐MNR/XNBR) was investigated. The tensile strength of the ionic blends was found to be greater than those of pure rubbers. The modulus, tensile, and tear strength of the blends dramatically increased with increasing levels of grafted anhydride. The ionic rubber blends also possessed superior physical properties compared to those of the corresponding nonionic rubber blends (MNR/XNBR). Dynamic mechanical thermal analysis and scanning electron microscopic studies were performed to verify the process of mixing. Fourier transform infrared spectroscopic studies were carried out to characterize the nature of specific intermolecular interactions between Zn‐MNR and XNBR chain segments. The results indicated that the ion‐ion (Zn⁺ ‐COO^?) interactions between Zn‐MNR and XNBR are formed at the interface, which provides the mean of compatibilization in the ionic rubber blends. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Influence of ZnO nanoparticles on the cure characteristics and mechanical properties of carboxylated nitrile rubber

Zinc oxide (ZnO) nanoparticles assembled in one dimension to give rod‐shaped morphology were synthesized. The effect of these ZnO nanoparticles (average particle size ～ 50 nm) as the curing agent for carboxylated nitrile rubber was studied with special attention to cure characteristics, mechanical properties, dynamic mechanical properties, and swelling. These results were compared with those of the conventional rubber grade ZnO. The study confirmed that the ZnO nanoparticles gave a better state of cure and higher maximum torque with a marginal decrease in optimum cure time and scorch time. The mechanical properties also showed an improvement. There was an increase in tensile strength by ～ 120%, elongation at break by ～ 20%, and modulus at 300% elongation by ～ 30% for the vulcanizate cured with ZnO nanoparticles, as compared with the one containing rubber grade ZnO. Dynamic mechanical analysis revealed that the vulcanizates exhibited two transitions—one occurring at lower temperature due to the T_g of the polymer, while the second at higher temperature corresponding to the hard phase arising due to the ionic structures. The second transition showed a peak broadening because of an increase in the points of interaction of ZnO nanoparticles with the matrix. The tan δ peak showed a shift towards higher T_g in the case of ZnO nanoparticle‐cured vulcanizate, indicating higher crosslinking density. This was further confirmed by volume fraction of rubber in the swollen gel and infrared spectroscopic studies. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Vulcanization of carboxylated nitrile rubber (XNBR) by a mixed zinc peroxide–sulphur system

Vulcanization of carboxylated nitrile rubber (XNBR) with a mixed system based on zinc peroxide and sulphur accelerators produces materials with favourable mechanical properties because of the formation of ionic aggregates which give the vulcanized compounds a certain rigidity. These properties are drastically reduced by the effect of saturated ammonia vapour which plasticizes the ionic aggregates. This plasticization, however, is reversible and the aggregates can be regenerated by addition of a solvent, which results in recovery and even improvement of the original properties such as stress at constant deformation, tensile strength, crosslinking density and storage modulus. The temperatures of the two transitions observed in the relaxation spectra, the glass transition of the polymer and the ionic transition corresponding to ionic aggregates, are displaced to higher values when ionic structures are regenerated. © 2000 Society of Chemical Industry     

中腈基含量液体丁腈橡胶的合成

以丁二烯(Bd)和丙烯腈(AN)为聚合单体,以过硫酸盐为引发剂,以硫醇为相对分子质量调节剂,在10 L聚合釜上采用自由基乳液聚合法合成了AN质量分数为(25±2)%的中腈基含量液体丁腈橡胶。研究了聚合配方及后处理工艺对聚合物性能的影响。结果表明,在聚合反应温度为(30±1)℃;过硫酸盐B 1.5~2.5份,硫醇5~6份,复配阴离子乳化剂A 2~4份;洗涤剂为90℃以上热水,用量为胶浆的1.5倍;干燥温度为(120±5)℃的条件下,可以制得Mn为(1 400±200),AN质量分数为(25±2)%的中腈基含量液体丁腈橡胶。     

Multi-walled carbon nanotube reinforced self-crosslinking hydrogenated carboxylated nitrile butadiene rubber latex film with improved properties

A dielectric self-crosslinking hydrogenated carboxylated nitrile butadiene rubber (HXNBR) latex film was prepared by diimide reduction hydrogenation of XNBR latex and the doping of multi-walled carbon nanotube (MWCNT). The structures of the HXNBR and XNBR were characterised by Fourier transform infrared spectroscopy (FTIR) and ¹HNMR, confirming the successful hydrogenation of XNBR. The mechanical, thermal, and electrical properties of the prepared HXNBR latex films were studied, and the HXNBR latex film reinforced by only 3?phr MWCNTs exhibited improved mechanical, thermal, and dielectric properties.     

羧基丁腈橡胶基阻尼复合材料的相态结构及动态力学性能

研究了羧基丁腈橡胶(XNBR)/受阻酚2,2′-亚甲基双-(4-甲基-6-叔丁基苯酚) (AO-2246)复合材料的相态结构及动态力学性能,并考察了短碳纤维(SCF)的加入对复合材料动态力学性能的影响.结果表明,XNBR/AO-2246复合材料中AO-2246的质量分数存在1个临界值(40%),当AO-2246质量分数小于该临界值时,体系呈现单相形态;当AO-2246质量分数大于该临界值时,体系呈现多相形态;XNBR/AO-2246复合材料只有1个玻璃化转变峰,随着AO-2246质量分数的增加,损耗因子峰值(tan δmax)先增大后减小,玻璃化转变温度(Tg)向高温方向移动至室温;当AO-2246质量分数为50%时,tan δmax高达3.5;加入SCF后,XNBR/AO-2246复合材料的tan δmax值大幅度下降至2.5左右,但当SCF质量分数为30%时,tan δmax值升高至2.8;SCF的加入使XNBR/AO-2246复合材料的Tg略有升高,且SCF用量越大,Tg越高,同时XNBR/AO-2246复合材料的储能模量大幅度增加.     

动态硫化丁腈橡胶/尼龙6热塑性弹性体的制备及性能

采用动态硫化法制备了丁腈橡胶/尼龙6热塑性弹性体(NBR/PA 6 TPV),考察了硫化体系、羧基丁腈橡胶(XNBR)以及增塑剂高密度氧化聚乙烯蜡(AC-316 A)和正丁基苯磺酰胺(BBSA)对TPV硫化特性、力学性能和微观形貌的影响。结果表明,以促进剂HVA-2/促进剂DM为硫化体系,动态硫化过程体系黏度的变化比以酚醛树脂/SnCl2为硫化体系时更平稳;但用后者制备TPV,其撕裂强度和扯断伸长率等力学性能更优,PA 6的结晶度更低。XNBR能对NBR和PA 6起到增容作用,当XNBR与NBR的质量比为10/90时,TPV的力学性能最好,NBR在PA 6中分散得最均匀。AC-316 A和BBSA都能对TPV起到增塑作用,随其用量的增加,体系黏度降低。