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对部分特种橡胶的一些技术进展进行了评述,这些橡胶包括氢化丁腈橡胶、NBR/PVC共混物、易加工型CR、耐寒CR、粉末型CR/甲基丙烯酸甲酯接枝橡胶、茂金属催化EPDM、EPDM/硅橡胶共混物、低压缩永久变形氟橡胶、氟橡胶/聚丙烯酸酯橡胶并用胶、四丙氟橡胶/EPDM并用胶、高抗撕硅橡胶,不用二段硫化的硅以及氯化聚乙烯等。 相似文献
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用孟山都流交仪测定了不同共混比的甲基乙烯基硅橡胶(VMQ)/EPDM共混混炼胶的流变性能;用网笼法测定了炭黑在共混体系两相中的比例;研究了薄通次数对共混硫化胶体积电阻率的影响;用透射电镜观察了硫化胶的形态。根据试验结果得出:适当并用比和炭黑填充量的VMQ/EPDM共混硫化胶具有高导电性的原因是:两相粘度相差较大,共混体系为明显的“海-岛”结构,而且炭黑在共混体系两相中的浓度不同;具有高导电性及其加工稳定性的VMQ/EPDM共混导电橡胶的最佳并用比例为80/20—70/30。 相似文献
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研究了橡胶型乙烯醋酸乙烯酯共聚物(EVM)/NBR共混比、硫黄和叔丁基酚醛树脂(2402树脂)硫化体系对共混物性能的影响,并对比了动态硫化和静态硫化共混物在性能上的差异。试验结果表明,EVM/NBR共混比显著影响共混物的力学性能,而采用NBR预先动态硫化的方法后,共混物胶料的挤出口型膨胀率明显减小,老化性能得到改善,同时减弱了硫黄和2402树脂等硫化体系对EVM硫化的影响,使多种硫化体系可以共存于共混物中。DSC分析表明EVM/NBR动态硫化共混物只有一个玻璃化温度,且介于EVM和NBR之间,说明EVM和NBR具有良好的相容性。 相似文献
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研究了硫化剂、相容剂、炭黑及共混比以MVQ/EPDM共混物力学性能的影响。提出了耐热水蒸气橡胶制品的合理配方,指出了提高共混胶的相容性及共硫化是获得优异性能产品的关键。 相似文献
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在逆流式冷却塔的空气阻力计算中,常常忽略了雨区阻力的计算,包括国标规范与高等教育的教科书等权威文献也未提及,根据工业塔的实测,这部分阻力占全塔空气阻力的1/6左右。本文根据冷却塔设计与运行的实践,并结合国内外学者对此的实验研究成果,经分析总结,给出了一个较为系统可行的计算方法,经验证与工业塔实测基本吻合,可供冷却塔设计中参考使用。 相似文献
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综述了聚邻苯二甲酰胺(PPA)的特性和应用,对部分PPA新品种制备方法及表征测试作了介绍,还介绍了PPA在耐热性、吸水性、尺寸稳定性、耐焊锡性等方面的研究进展。 相似文献
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《Ceramics International》2022,48(21):31909-31913
Enamel–metal composite materials with high strength and corrosion resistance are often used for fabricating enameled pressure vessels for pharmaceutical and chemical production. However, the low bending resistance of the enamel can result in the cracking and delamination of the enamel layer, leading to the loss of corrosion resistance of the enameled pressure vessel, which can result in accidents. Here, based on the goal of increasing the bending resistance of the enamel to prolong its service life, the effect of β-Si3N4 whiskers on the mechanical properties of enamel was studied by three-point bending tests. The effect of β-Si3N4 whiskers on the acid and alkali corrosion resistance of enamel was studied using aqueous H2SO4 and NaOH solutions, respectively. A sudden change in the force of an enameled sample under the three-point bending test was used to evaluate the bending resistance of the enamel–metal samples, and can also be used to evaluate the mechanical properties of other comparable materials. With the addition of 0.5 wt% β-Si3N4 whiskers, the bending resistance was significantly improved, along with the acid and alkali corrosion resistance. These findings are expected to provide guidance for the design and production of enamel-metal vessels with improved performance that can significantly lengthen the service life of enameled pressure vessels and reduce the occurrence of accidents. 相似文献
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介绍了电阻涂料底漆、面漆的种类和各类电阻涂料底漆和面漆的组成、特点及技术规格。同时,还简介了环氧型、油墨型及有机硅型标志涂料的特点和技术指标。 相似文献
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Rundong Fan Huizhong Zhao Han Zhang Pengda Zhao Jianwei Chen Xianghui Wang 《Ceramics International》2019,45(9):11204-11215
Alumina–chromium slag (ACS), a cheap and abundant refractory raw material comprising aluminum–chromium oxides and β-Al2O3, is a byproduct of ferrochrome smelting. For this reason, we investigated the relationships between composition and mechanical properties, abrasion resistance, oxidation resistance, and resistance to iron slag erosion for Al2O3–SiC–C trough castables in which ACS was substituted for alumina. Due to the presence of β-Al2O3 in ACS, the aluminum-chromium slag reacted with SiO2 to form a low-melting phase of albite and promoted the formation of mullite, which filled the pores at high temperatures and reduced the porosity, thereby promoting densification and strengthening of the sample. The cold mechanical properties of the sample and the normal temperature wear resistance were enhanced, but the high-temperature mechanical properties and the resistance to iron slag corrosion of the sample were impaired. According to the results of the anti-oxidation experiment, the presence of β-Al2O3 in the ACS reduced the porosity and made the sample more dense, which remarkably improved oxidation resistance of the sample. For industrial production requirements, ACS substitution should not exceed 48?wt% due to of thermomechanical properties and anti-slag corrosion performance in Al2O3–SiC–C trough castables. 相似文献
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《Ceramics International》2022,48(10):13987-13995
The purpose of this paper was to develop ceramics materials with high thermal shock resistance and corrosion resistance for preparing gas blowing components. In this paper, MgO-rich MgO–ZrO2 ceramics were obtained by using MgO powder and ZrO2 powder as starting materials and CeO2 as an additive. Changes in the properties in terms of thermal shock resistance, mechanical properties, and slag corrosion-resistance with chemical compositions were examined correlated to microstructure and phase changes. Especially, the effect of doping CeO2 on phase transition of zirconia in MgO-rich system was discussed. The results showed that doping amount of CeO2 significantly improved properties of MgO–ZrO2 ceramics. Especially when doping amount of CeO2 was 2 wt%, residual strength ratio was enhanced over 100% after thermal shock testing. In samples doped with CeO2, ZrO2 was stable in cubic or tetragonal form due to complete solution of CeO2, which was important reason for the improvement of various properties of MgO–ZrO2 ceramics. 相似文献
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