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低相对分子质量反式1,4-聚异戊二烯蜡在橡胶助剂造粒中的应用 总被引:1,自引:2,他引:1
用低相对分子质量反式1,4-聚异戊二烯蜡作载体对硫黄、氧化锌和促进剂CZ进行造粒,研究助剂造粒对NR/SBR胶料性能的影响;在助剂造粒过程中加入表面活性剂,考察其对造粒效果及BR/SBR胶料性能的影响。结果表明,助剂造粒后可增大NR/SBR胶料的门尼粘度,对胶料的正硫化时间和硫化胶的物理性能影响不大;在助剂造粒过程中加入表面活性剂,可提高BR/SBR胶料的混炼速度,改善加工性能,对硫化胶的物理性能影响不大。 相似文献
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乙丙橡胶和丁腈橡胶的并用研究 总被引:1,自引:2,他引:1
介绍了乙丙橡胶和丁腈橡胶并用胶的混炼工艺,乙丙橡胶的类型、硫化体系、均匀剂及两种橡胶的并用比例对并用胶料的硫化特性、物理机械性能、耐油性能及低温性能的影响。结果表明,并用时,乙丙橡胶应选用硫化速度较快的第三单体为ENB型及碘值较高的类型;DCP 硫黄、促进剂体系是并用胶料的有效硫化体系;并用胶制备时宜采用两种胶分别配合混炼再按比例掺混的混炼工艺;均匀剂R60,H501能有效提高并用胶料的硫化速率。任意并用比例的胶料均有着良好的物理机械性能但其耐油性能及低温性能不同。 相似文献
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研究了活化剂Struktol A-73在天然橡胶及天然橡胶与丁苯橡胶并用胶中的应用特性,结果表明:胶料中加入Struktol A-73可改善胶料的抗硫化返原性和热稳定性;提高胶料的硫化效率;改进胶料的动态性能;降低胶料的生热和压缩永久变形;与噻唑类硫化促进体系并用,无亚硝胺污染环境的危险;对钢丝粘合性能造成的影响,在胶料老化之后即可降至最小;混炼工艺性能良好。它是一种特别有效的硫化活化剂,一般用量 相似文献
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研究工程机械轮胎胎体胶混炼工艺改进对胶料性能的影响。结果表明:通过将炭黑分2段加入,并将防老剂和塑解剂分开加入,混炼效率提高,塑解剂效能得到保护;与改进前胶料相比,改进后胶料的门尼粘度降低,硫化特性变化不大,硬度、定伸应力、拉伸强度和撕裂强度相当,H抽出力明显增大,自粘性显著提高,流动性好,压延半成品尺寸稳定性提高。 相似文献
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探讨促进剂、多功能助剂PA、防焦剂苯甲酸和白炭黑对平衡硫化体系NR胶料硫化特性和物理性能的影响。试验结果表明,采用促进剂D/NOBS并用的NR胶料焦烧时间较长和正硫化时间较短,硫化胶的拉伸强度、拉断伸长率和撕裂强度较高;加入多功能助剂PA使胶料的焦烧时间略有延长,硫化胶的拉断伸长率提高;采用苯甲酸作防焦剂可以大幅度缩短胶料的正硫化时间,提高硫化胶的拉伸强度、拉断伸长率和硬度;白炭黑和偶联剂Si69(质量比100/3)直接加入的胶料正硫化时间明显缩短,硫化胶的拉断伸长率和撕裂强度较大。 相似文献
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Dinesh Singh J. K. Gehlawat Musti S. Rao 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》1990,47(2):127-136
Oslefins and diolefins are important intermediates in the petrochemical industry and the future promises a further substantial increase in demand. While several catalysts have been formulated in the past for the abstraction of hydrogen from butenes and propylene, these catalysts are inefficient in the abstraction of first hydrogen from butane. Bismuth molybdates (β and γ-phases) containing iron oxide and supported on alumina are used as catalysts in the present investigation on the oxidative dehydrogenation of n-butane. Effects of catalyst content, temperature and oxygen: n-butane ratio on conversion and selectivity to butadiene and (C4H8 + C4H6) are studied in the following ranges of experimental conditions: β-bismuth molybdate/100 mol support I(K), 3–9; γ-bismuth molybdate/100 mol support I(K), 5-20; temperature, 400–500°C; O2: butane ratio, 0.6:1.7. 相似文献
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A viscometer used to measure the viscosity of 10 μl of a liquid, must be miniaturized down, and the liquid velocity gradient in the channel used to determine the viscosity coefficient. Two major factors that affect the liquid velocity are the mechanical forces exerted by the mechanical motors and electromagnetic forces. In this study, electrowetting on dielectric (EWOD) is adopted to drive liquids. Variously sized electrodes on a chip, and two shapes of channel are employed to measure the velocity gradient to determine the viscosity coefficient. The device is fabricated by microelectromechanical system (MEMS) technology. The dielectric layer used in EWOD has a high dielectric constant, BST (Ba0.7Sr0.3TiO3), to reduce the required applied voltage; its surface is coated with hydrophobic polymer, polytetrafluoro-ethylene (PTFE, Teflon® AF DuPont). Experimental results demonstrate that liquids can be pulled at 660 μm/s in linear channels by applying a voltage of 15 V. 相似文献
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考登钢作为一种高耐候结构钢,广泛应用于各个领域。在火力发电方面,考登钢主要应用在工作环境比较恶劣的烟气加热器和空气预热器中。考登钢表面涂搪的目的就是进一步提高其耐腐蚀性能,延长使用寿命。为了提高考登钢元件的使用寿命,对考登钢表面涂搪瓷的可行性、密着性能、瓷釉、工艺控制、质量保证等方面进行了研究。 相似文献
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研究了温度和pH值对漆酶酶活以及漆酶处理纤维压制纤维板性能的影响。结果表明,pH较低、温度较高时漆酶酶活较高,压制的纤维板强度性能较好。但温度太高(60~80℃),延长加热时间,漆酶稳定性变差,酶活明显降低,压制纤维板的强度下降。 相似文献
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In reexamining medium effects on photochemical reactions, we have emphasized those on unequilibrated excited species such as the Franck-Condon species. Despite recent advances in femtochemistry, such a discussion in molecular photochemistry is uncommon, and the problem remains challenging on account of the extremely short-lived excited species. However, in such cases, a small perturbation resulting from, for example, weak guest-host interactions could turn into a determining factor in dictating the course of a photochemical channel of deactivation. Examples of medium-directed diabatic processes have been examined with this idea in mind. A modified view on rhodopsin photoisomerization is presented along with the consideration that confinement does not necessarily lead to inhibition of reactions of the trapped substrate. 相似文献
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采用密度泛函理论(DFT)考察了丙烷在Pt(111)表面上脱氢生成丙烯的反应机理。通过在Pt(111)面上预吸附一定数量H原子模拟共吸附H对丙烷脱氢过程的影响。结果表明:H共吸附能降低丙烷及其脱氢产物的吸附能,促进丙烯脱附,有利于提高丙烯的选择性;H共吸附会导致丙烷脱氢能垒变大,降低催化剂的脱氢活性;共吸附的影响随着H覆盖率增加而增大。 相似文献