主减速器橡胶密封圈性能衰减模型及日历寿命评估

目的 构建主减速器橡胶密封圈储存/装机条件下的性能衰减模型,评估其实际储存日历寿命、储存/装机条件下的折算系数。方法 将功能结构件实际尺寸（实际装配、初始轴向厚度和压缩时轴向厚度）、实际生产产品尺寸和安全裕度相结合,确定橡胶密封件的失效判据。对实际使用的FX-4、FX-17橡胶密封圈2种初始压缩率的装机状态下进行5个温度点的加速老化试验,测定2种橡胶密封圈压缩永久变形率的老化指标参数,利用回归分析得到相应的衰减模型,结合实际储存13a的橡胶密封圈的压缩永久变形率进行检验,确定储存/装机条件下的折算系数。结果 以25%为失效判据,橡胶密封圈储存年限可达19.8 a。结论 为了保证使用安全和外场计算方便,FX-4密封圈装机使用1 a相当于储存2 a,FX-17密封圈装机使用1 a相当于储存3 a。     

废丁基橡胶再生及其应用

再生胶、胶粉及活化胶粉是废丁基橡胶回收利用的主要途径和方法,其中再生胶应用效果最好。综述了废丁基橡胶的再生方法及其应用,重点介绍了废丁基橡胶的常温塑化法再生工艺及机理,并结合实验,介绍了丁基再生胶用于制备防水卷材的一些经验。     

不同因素耦合对密封橡胶老化特性的影响

目的 研究某密封橡胶材料在工况环境下的老化规律和特性,开展静载荷/温度/介质等多因素耦合的加速老化试验。方法 设计3种老化条件(90 ℃热空气、90 ℃热空气压缩、90 ℃热油压缩)模拟实际服役环境开展实验室加速研究。通过质量、硬度、压缩永久形变率等橡胶老化前后宏观性能变化,结合其化学结构和微观形貌变化进行老化特性研究。结果 热油压缩老化条件下,橡胶质量随时间变大,硬度变小,压缩永久形变变大,热稳定性变差,化学结构变化较小;热空气压缩条件下,压缩永久形变变大,其他物化性能变化较小;热空气条件下,硬度变大,烷基含量减少,其他变化较小。扫描电镜结果显示,2种压缩条件下,橡胶表面都出现颗粒状物质和条状纹理。以上结果说明,油在隔绝外界氧气的同时,会渗透到橡胶内部,引起软化,热空气介质加速橡胶热氧老化和材质硬化,压缩条件在抑制热氧老化同时,可加速应力松弛等物理老化作用的发生。结论 密封橡胶在不同服役环境下发生的主要老化反应并不一致,在热空气下,橡胶性能退化与热氧老化等化学老化作用有关,而在油介质和压缩状态下,橡胶性能劣化与物理老化作用更相关。     

典型橡胶制品业VOCs排放特征及对周边环境影响

选取衡水市3家典型橡胶制品企业作为研究对象,通过GC-MS/FID对其VOCs排放特征进行研究,并运用最大增量反应活性系数(maximum incremental reactivity,MIR)和气溶胶生成系数(fractional aerosol coefficient,FAC)分别对其臭氧生成潜势(ozone formaiton potential,OFP)和二次有机气溶胶(secondary organic aerosol,SOA)生成潜势进行评估.结果表明,橡胶制品行业的VOCs排放种类主要包括烷烃类、酮类、醛类、醇类和苯系物等.对于传统的只有炼胶工艺和硫化工艺的橡胶制品企业,其特征污染物主要为酮类和醇类,而对于涉及涂胶工艺和喷漆工艺的橡胶制品企业来说,其特征污染物为苯系物.对典型生产工艺的臭氧和SOA的生成潜势进行了评估:臭氧影响方面,对于不涉及涂胶和喷漆工艺的橡胶制品企业,臭氧生成贡献主要来自于含氧烃,对于涉及涂胶和喷漆工艺的企业,由于胶黏剂和漆料等有机溶剂的大量使用,苯系物对臭氧生成的贡献还是要远远大于其它VOCs物种,占到了VOCs总贡献的82.9%; SOA影响方面,...     

Mechanism insight into the formation of H2S from thiophene pyrolysis: A theoretical study

• Possible formation pathways of H₂S were revealed in thiophene pyrolysis. • The influence of hydrogen radicals on thiophene pyrolysis was examined. • Thiophene decomposition starts with hydrogen transfer between adjacent C atoms. • The presence of hydrogen radicals significantly promotes the formation of H₂S. Pyrolysis is an efficient and economical method for the utilization of waste rubber, but the high sulfur content limits its industrial application. Currently, the migration and transformation of the element S during pyrolysis of waste rubber is far from well known. In this work, a density functional theory (DFT) method was employed to explore the possible formation pathways of H₂S and its precursors (radicals HS· and S·) during the pyrolysis of thiophene, which is an important primary pyrolytic product of rubber. In particular, the influence of reactive hydrogen radicals was carefully investigated in the thiophene pyrolysis process. The calculation results indicate that the decomposition of thiophene tends to be initiated by hydrogen transfer between adjacent carbon atoms, which needs to overcome an energy barrier of 312.4 kJ/mol. The optimal pathway to generate H₂S in thiophene pyrolysis involves initial H migration and S-C bond cleavage, with an overall energy barrier of 525.8 kJ/mol. In addition, a thiol intermediate that bears unsaturated C-C bonds is essential for thiophene pyrolysis to generate H₂S, which exists in multiple critical reaction pathways. Moreover, the presence of hydrogen radicals significantly changes the decomposition patterns and reduces the energy barriers for thiophene decomposition, thus promoting the formation of H₂S. The current work on H₂S formation from thiophene can provide some theoretical support to explore clean utilization technologies for waste rubber.     

Quality improvement of pyrolysis oil from waste rubber by adding sawdust

This work was aimed at improving the pyrolysis oil quality of waste rubber by adding larch sawdust. Using a 1 kg/h stainless pyrolysis reactor, the contents of sawdust in rubber were gradually increased from 0%, 50%, 100% and 200% (wt%) during the pyrolysis process. Using a thermo-gravimetric (TG) analyzer coupled with Fourier transform infrared (FTIR) analysis of evolving products (TG–FTIR), the weight loss characteristics of the heat under different mixtures of sawdust/rubber were observed. Using the pyrolysis–gas chromatography (GC)–mass spectrometry (Py–GC/MS), the vapors from the pyrolysis processes were collected and the compositions of the vapors were examined. During the pyrolysis process, the recovery of the pyrolysis gas and its composition were measured in-situ at a reaction temperature of 450 °C and a retaining time of 1.2 s. The results indicated that the efficiency of pyrolysis was increased and the residual carbon was reduced as the percentage of sawdust increased. The adding of sawdust significantly improved the pyrolysis oil quality by reducing the polycyclic aromatic hydrocarbons (PAHs) and nitrogen and sulfur compounds contents, resulting in an improvement in the combustion efficiency of the pyrolysis oil.     

西双版纳大面积橡胶种植与生态环境影响

分析橡胶种植对西双版纳热带雨林的破坏及对生态环境的影响,提出保护热带森林资源走特色发展之路的对策.     

用丁苯橡胶滤柱处理含油废水的研究

研究了用丁苯橡胶滤柱处理含油废水的可行性,探讨了不同条件下对含油废水破乳除油的影响参数,并对实际废水进行了处理。结果表明,在滤柱高50mm、线流速为3mL/s、水温为20℃的条件下,对含油量为500～600mg/L的含油废水进行处理,去除率可达80%左右。因此,该滤柱可用于含油废水的初级处理。     

不同生产阶段产生的压电陶瓷废品对氯化丁基橡胶阻尼减振性能的影响

将压电陶瓷生产过程中不同生产阶段产生的废品应用于氯化丁基橡胶阻尼减振材料，并比较了它们对阻尼减振性能的影响。     

白炭黑补强氟硅橡胶热空气老化机理研究

目的研究热空气老化过程中白炭黑补强氟硅橡胶的老化机理。方法开展不同加速老化温度点下白炭黑补强氟硅橡胶热空气老化试验,对老化过程中材料的力学性能进行研究,同时采用热重分析、衰减全反射红外光谱、交联密度分析以及固体核磁等技术,对200℃热空气老化过程中材料的微观结构变化进行分析。结果低温环境中白炭黑氟硅橡胶拉伸强度和扯断伸长率变化较小,高温环境中变化趋势增大,邵尔A硬度在整个老化过程中没有明显变化。结论白炭黑补强氟硅橡胶的老化机理主要是交联键的断裂和侧链三氟丙基的分解,同时还可能伴随有部分主链的破坏。