水溶性Kevlar纳米纤维对羧基丁腈橡胶力学性能和 动态力学性能的影响

制备了水溶性Kevlar纳米纤维(hANFs)/羧基丁腈橡胶(XNBR)复合材料,研究了hANFs的用量对橡胶的力学性能和动态力学性能的影响。结果表明,当hANFs用量为5份时,复合材料的拉伸强度和撕裂强度分别提高了203%和103%,储能模量和玻璃化转变温度也有明显提高。     

改性芳纶纳米纤维对羧基丁腈橡胶力学性能的影响

采用改性芳纶纳米纤维(m-ANFs)填充羧基丁腈橡胶(XNBR)硫化胶,研究了不同用量的m-ANFs对XNBR硫化胶的力学性能的影响。结果表明,m-ANFs较好地分散在橡胶基体中,可有效地改善XNBR硫化胶的力学性能,当m-ANFs的用量为5. 0份时,XNBR硫化胶的拉伸强度、扯断伸长率、100%定伸应力及撕裂强度分别提高了182%、42%、14%和101%。     

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。     

用分子动力学模拟研究丁二烯微观结构对丁腈橡胶物理机械性能的影响

采用分子动力学模拟的方法对基于3种不同丁二烯键合结构建立的丁腈橡胶模型(A、B、C模型)进行了模拟计算,以考察丁二烯微观结构对丁腈橡胶物理机械性能的影响.采用恒定应变法计算模型的物理机械性能,然后将模型与铁原子层结合建立摩擦副模型,利用剪切模拟分析丁腈橡胶摩擦过程的磨损机理.结果表明,与A模型和C模型相比,B模型分子链...     

含有纳米颗粒的悬浮纳米液滴蒸发特性的分子动力学模拟

采用非平衡分子动力学模拟方法,研究单个含有固体金属纳米颗粒的悬浮纳米液滴的蒸发特性。模拟结果表明,含有金属纳米颗粒的悬浮球形纳米液滴,在蒸发过程中基本保持球形不变;模拟温度越高,金属纳米颗粒的质量分数越大,纳米流体液滴的球形度越小。当蒸发过程开始时,纳米流体液滴的蒸发速率很大,而且模拟温度越高,蒸发速率越大,随后,蒸发速率急剧下降;随着蒸发过程的进一步进行,蒸发速率缓慢下降。金属纳米颗粒的种类和质量分数,对悬浮纳米流体液滴的蒸发速率影响不大。     

水基纳米流体传递性质的分子动力学模拟研究

采用平衡分子动力学方法,探讨了系统温度、纳米颗粒的体积分数及能量因子对水基纳米流体的热导率和黏度的影响。模拟结果表明,随着系统温度的升高,水基纳米流体的热导率增大,而黏度减小;水基纳米流体的热导率及黏度均随着纳米颗粒体积分数的增加而增大,当纳米颗粒的体积分数2%时,水基纳米流体的热导率增幅较小;随着纳米颗粒能量因子的增加,水基纳米流体的热导率增大,而黏度基本不变。     

粗糙壁面上水纳米液滴润湿性的分子动力学模拟

采用分子动力学模拟技术,研究水纳米液滴在粗糙壁面上的润湿性,探讨壁面形貌、柱高和相面积分数对接触状态和接触角的影响。模拟结果表明,在粗糙度因子相同的情况下,水纳米液滴在栏栅形、方柱矩阵形及凹坑矩阵形三种粗糙壁面上的接触角相差不大。对于疏水性壁面,当柱高较小时,水纳米液滴的接触状态为Wenzel模式;当柱高较大时,接触状态为Cassie模式,随着柱高的增加,接触角逐渐增大。在不同的相面积分数下,接触状态始终处于Cassie模式;随着相面积分数的增加,接触角逐渐减小。对于中性壁面,水纳米液滴的接触角随柱高变化不大,接触状态均为Wenzel模式。当相面积分数较小时,接触状态为Wenzel模式;当相面积分数较大时,接触状态为Cassie模式,接触角基本不变。对于亲水性壁面,当相面积分数较小时,水纳米液滴的接触状态为Wenzel模式;当相面积分数较大时,接触状态为Cassie模式。在不同的柱高下,接触状态均为Wenzel模式。     

纳米结构表面液体沸腾传热的分子动力学模拟

为了从纳米尺度了解表面结构和润湿性对池沸腾液体与固体壁面的传热性能,本文采用分子动力学方法研究了超亲水至超疏水不同润湿性的液体氩在光滑表面和含凹、凸半球纳米结构表面的沸腾传热过程,分析了三种表面上液氩在受热过程的形态、温度、热流密度等相关参数的变化情况。结果表明,液氩层沸腾过程大致可分为液氩层吸附于固体表面和液氩层从壁面脱离两个加热阶段,当液氩层吸附于固体表面时,温度升高、热流密度及气态氩原子产生速度均大于液氩层脱离壁面时的情况,在这两个阶段亲水表面上氩原子温度变化有明显的拐点,而疏水表面在两个阶段加热过程相差不大。亲水表面上的微结构能吸附更多液氩原子,促进了气泡产生及加速温度、热流密度的变化,而在疏水及超疏水微结构表面,微纳结构与液氩间的气膜层促进了气泡产生,计算结果为池沸腾传热及微结构选择提供了理论依据。     

纳米级二氧化锆的表征和应用

纳米二氧化锆是一种新型的高科技材料，有着广泛而重要的用途。本文根据国内外研究制备的最新进展及其发展趋势，综述了纳米级二氧化锆表征方法和近年来新的应用领域和研究前沿。     

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.     

Friction properties of graphene reinforced nitrile rubber composites after thermal oxidation aging: Experiment and molecular dynamics simulation

We established friction models for pure NBR, GNS/NBR, and GO/NBR composites through molecular dynamics (MD) simulation. Our study focused on the impact of GNS and GO on the friction properties of nitrile rubber (NBR) composite materials after undergoing thermal oxygen aging. Based on the simulation results, it can be observed that the GNS/NBR and GO/NBR composites' coefficient of friction (COF) decreases by 20.8% and 24.8%, respectively, at 348 K. Additionally, the abrasion rate is reduced by 17.4% and 25.7%, respectively, for the same composites. Adding GNS and GO can effectively improve the friction performance of the NBR composite system, and compared with GNS, GO shows a better enhancement effect. Pure NBR and GO/NBR composite materials were prepared by mechanical blending method, and the friction properties of GO-enhanced NBR composite materials were studied. The experimental results show that the GO/NBR composite material can maintain a low friction and wear coefficient after thermal and oxygen aging. It shows that adding GO can effectively improve the friction properties of NBR composite systems and slow down the weakening effect of aging on the friction properties of NBR composite materials. This is because the GO surface contains wealthy functional groups such as epoxy groups, which enhances the binding strength between the GO and NBR interface so that the GO/NBR composite material exhibits better friction properties and thermal oxygen aging resistance. In addition, the wear surface was characterized by scanning electron microscopy (SEM), revealing the damage mechanism of friction and wear of NBR composite materials.     

Morphology,mechanical and viscoelastic properties of nitrile rubber/epoxidized natural rubber blends

A new class of blend membranes from blends of nitrile rubber (NBR) and epoxidized natural rubber (ENR) has been prepared and their morphology, miscibility, mechanical, and viscoelastic properties have been studied. The ebonite method was used to study the blend morphology of the membranes. The morphology of the blends indicated a two‐phase structure in which the minor phase is dispersed as domains in the major continuous phase. The performance of NBR/ENR blend membranes has been studied from the mechanical measurements. The viscoelastic behavior of the blends has been analyzed from the dynamic mechanical data. An attempt was made to relate the viscoelastic behavior with the morphology of the blends. Various composite models have been used to predict the experimental viscoelastic data. The area under the linear loss modulus curve was larger than that obtained by theoretical group contribution analysis. The homogeneity of the system was further evaluated by Cole–Cole analysis. Finally, a master curve for the modulus of the blend was generated by applying the time–temperature superposition principle. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 1561–1573, 2005     

累托石/丁腈橡胶纳米复合材料的结构与性能

用乳液共混共凝法制备了累托石／丁腈橡胶(NBR)复合材料,分别进行了透射电镜分析和X射线衍射分析,研究了其力学性能和气体阻隔性能。结果表明,累托石以厚度为10．00nm左右的晶束均匀分散于NBR中;累托石／NBR复合材料属于隔离型纳米复合材料;与传统的炭黑／NBR复合材料和白炭黑／NBR复合材料相比,累托石／NBR纳米复合材料具有高的邵尔A型硬度和300％定伸应力．尤其是其气体阻隔性能得到了显著提高。     

含氟单体改性丁腈橡胶的制备与性能

采用含氟单体甲基丙烯酸六氟丁酯、丁二烯、丙烯腈与反应型偶联剂直接进行乳液共聚制备含氟单体改性丁腈橡胶,考察了反应型偶联剂的种类及用量对聚合产物结构及性能的影响。结果表明,反应型偶联剂Q 2可与丁二烯、丙烯腈、含氟单体进行四元共聚,当含氟单体甲基丙烯酸六氟丁酯与偶联剂Q 2的质量比为1.50/1.50时,含氟单体改性丁腈橡胶的综合性能较佳,拉伸强度达到25.5 MPa,扯断伸长率为377%,耐热空气老化性能较好。     

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。     

复合乳化体系合成丁腈橡胶3604性能的主要影响因素

采用松香酸皂、油酸皂和萘磺酸钠甲醛缩合物复合乳化体系,通过热法合成丁腈橡胶NBR3604,考察了影响生胶门尼黏度及硫化胶拉伸强度和扯断伸长率等的主要因素。结果表明,合成NBR3604 较适宜的配方和工艺条件为: 丁二烯56 份( 质量) ,丙烯腈44 份,软水275 份,过硫酸钾0. 5 份,三乙醇胺0. 125 份,调节剂丁0. 45 ～ 0. 60 份,乳化剂3 ～ 4 份且松香酸皂与油酸皂质量比为4 /6 或5 /5,聚合温度( 30 ± 1) ℃,单体转化率( 70 ± 2) %。在此条件下的反应过程平稳,产品各项性能符合指标要求,重复性较好。     

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。