硫化时间及硫化体系对粘土胶热氧老化性能的影响

用热空气老化试验和热分析法讨论了硫化时间和硫化体系对粘土胶热氧老化性能的影响。结果表明,粘土胶由于热氧性能敏感,在硫化曲线允许的范围内,硫化时间以２０ｍｉｎ为宜。采用有效硫化体系和半有效硫化体系硫化粘土胶可以使其具有较好的热氧老化性能。     

Resin‐vulcanized NBR: Suitability of rheometric parameters for the calculation of cure kinetic constants

Several mechanisms can be used to describe the vulcanization process, and study of the reactions that actually take place can be done through different techniques. In this work, two methods that used rheometric parameters to calculate the kinetic constant were compared for the cure of nitrile rubber with a system of phenolic resin, polychloroprene, and zinc oxide. The formulations and data analysis were based on a complete factorial experiment design. The results enabled the identification of the influence of each parameter involved in the vulcanization process and the suitability of the two methods used. © 2002 John Wiley & Sons, Inc. J Appl Polym Sci 84: 505–513, 2002; DOI 10.1002/app.2354     

动态硫化热塑性硫化胶研究进展

热塑性硫化胶(TPV)是一种在常温下具有橡胶高弹性、高温下能塑化成型的新型材料,性能优异且发展迅速。本文综述了TPV的加工设备、制备工艺、硫化体系、微观相结构(包括"海-岛"结构、"核-壳"结构和"双连续相"结构)、改性方法以及功能型TPV的研究,并对TPV的发展前景作出展望。     

A new approach for kinetic modeling and optimization of rubber molding

Although extensive research has been carried out on the understanding of the complex vulcanization process, the influence of reversion through exposure time and temperature on the vulcanization degree remains unclear. Therefore, the main aim of this study was a novel optimization approach that can help the industrial practitioners to select the optimal operating parameters, exposure time, and molding temperature, to achieve desired vulcanization degree of selected product. Spheres of four different diameters (2.5, 5, 10, and 20 cm) were selected as test geometry for simulation and optimization of rubber molding. Obtained vulcanization rheometer data for commercially available rubber blend (NR/SBR) were fitted by a new modeling approach, dividing vulcanization curve into two fitting sets: curing and reversion. The heat transfer equations for chosen geometry were coupled with proposed kinetic model. A new temperature-dependent kinetic parameter x, as the maximal reversion degree, was introduced, enabling determination of the lowest operating molding temperature (T_min = 132.36 °C), preventing high reversion and overheating of the rubber product. The final optimization goal was assessment of the optimal temperature and vulcanization time dependence on the rubber products dimensions. Proposed models have precise prediction with R² values greater than 0.8328 and MAPE less than 2.3099%.     

Rice husk ash filled natural rubber. I. Overall rate constant determination for the vulcanization process from rheometric data

Black rice husk ash (BRHA) and white rice husk ash (WRHA) were incorporated into natural rubber (NR) using a laboratory‐size two‐roll mill. A conventional vulcanization system (CV) was chosen and cure studies were carried out on a TI‐100 Curometer. The torque curves were obtained at 150, 160, 170, and 180°C. The overall rate and the apparent activation energy for the vulcanization process were calculated for each compound assuming that vulcanization follows first‐order kinetics. For comparison purposes, two commercial fillers, precipitated silica (Zeosil‐175) and carbon black (N762), were also used. It was observed that addition of WRHA to NR compounds increased the cross‐linking rate and lowered the apparent activation energy more markedly than the other fillers. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 1194–1203, 2003     

氟橡胶及硫化机理概述

介绍了氟橡胶的主要种类及特点、常用的4种硫化体系和硫化机理,分析了有机二胺类、双酚类、有机过氧化物类及辐射交联类硫化体系的优缺点及其对硫化胶性能的影响,指出了双酚类硫化体系是目前常用的硫化体系,认为有机过氧化物类硫化体系可为氟橡胶带来优异的性能.     

Rice husk ash filled natural rubber. III. Role of metal oxides in kinetics of sulfur vulcanization

In preceding investigations the overall rate and apparent activation energy for the vulcanization process were calculated for natural rubber compounds, assuming that vulcanization follows first‐order kinetics. It was observed that the addition of white rice husk ash (WRHA) increased the rate of crosslinking and lowered the apparent activation energy more profoundly than commercial fillers, precipitated silica (Zeosil‐175) and carbon black (N762), with a conventional vulcanization system. In this work, a specific model for the vulcanization process accelerated by N‐cyclohexylbenzothiazole sulfenamide was used to investigate the real role of WRHA in crosslink formation. Cure studies were carried out at 150°C, and the kinetics constants were evaluated. In relation to the other fillers, WRHA seems to develop catalytic activity, resulting in a positive effect on the specific rate of crosslink formation. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 1519–1531, 2003     

橡胶硫化过程数值模拟研究进展

硫化作为橡胶制品成型过程中的关键工序，决定着制品的使用性能与尺寸精度，通过模拟仿真技术有助于实现对硫化过程的精确控制以及减少能量消耗。基于此，从微观尺度和宏观尺度两个层面综述了橡胶硫化过程数值模拟的研究进展，重点分析了理论与经验硫化反应动力学模型的发展现状。最后，指出了橡胶硫化过程数值模拟的发展方向与趋势。     

硫化体系对燕化EPDM中试产品性能的影响

研究了硫黄硫化体系和过氧化物体系对燕化中试产品三元乙丙橡胶(EPDM)性能的影响。实验结果表明,硫黄硫化体系中硫黄用量为1.5份时胶料物理机械性能最好;硫黄用量为2份时,胶料耐热老化性能最好。硫黄硫化体系中,二硫化四基秋兰姆(TMTDM)、2硫醇基苯并噻唑(M)和N-环己基-2-苯并噻唑次磺酸胺(CZ)3种促进剂并用时协同作用较好,胶料硫化速度最快,力学性能最好;促进剂TMTD用量为1.5份时,胶料压缩永久变形最小,耐热性能最好。过氧化物硫化体系中,当DCP用量由2份增加至5份时,胶料硫化速度提高,力学性能下降,压缩永久变形性能有一定改善。三烯丙基异氰脲酸酯(TAIC)用量为5份时,胶料压缩永久变形最小,耐热氧老化性能最好。     

丁腈橡胶硫化反应动力学研究

设计了促进剂A 4种不同用量的丁腈橡胶配方;基于配方,先利用密炼机将丁腈橡胶、硬脂酸和ZnO混炼,再利用开炼机加入硫黄、促进剂和防老剂,再利用无转子硫化仪分别测试了160℃、170℃和180℃下胶料硫化曲线;基于硫化曲线计算出了每组配方胶料硫化反应速率常数K和活化能Ea。结果表明,在焦烧期时,NBR硫化反应为非一级反应,真正的一级反应开始于硫化速率达到最大时,即tdis;焦烧期后的反应可分为2个阶段且遵循一级动力学反应规律。