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研究了混炼工艺对Si-69改性白炭黑填充HPR850/CB24的影响,混炼工艺区别如下,是否具有150℃的保温平台,白炭黑是否一次投料。实验结果表明,150℃的保温平台和白炭黑一次投料的混炼工艺能够改善白炭黑的分散,抑制白炭黑的填料网络,并且能促进白炭黑、Si69、橡胶分子链彼此间的硅烷化反应,交联密度也得到了显著的提高。同时保证了硫化胶具有较好的磨耗性能、力学性能。 相似文献
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研究混炼工艺对白炭黑硅烷偶联反应程度及胶料性能的影响。结果表明:随着白炭黑硅烷偶联反应程度的增大,胶料的门尼焦烧时间延长,硫化速度加快,小应变下的模量减小,Payne效应降低,填料与填料之间的相互作用减弱,70℃时的损耗因子明显减小,白炭黑在胶料中的分散均匀性提高;白炭黑硅烷偶联反应程度对混炼温度的敏感度较高,混炼温度对硅烷偶联反应程度的影响大于混炼时间的影响;当混炼温度为140~145℃、混炼时间为100~180 s时,胶料的物理性能最佳。通过计算白炭黑硅烷偶联反应的表观活化能,得到大配合试验胶料混炼工艺的最佳混炼时间。 相似文献
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研究了不同混炼时间下,采用密炼机及烘箱保温处理工艺对硅烷偶联剂Si 69原位改性白炭黑填充天然橡胶(NR)性能的影响。结果表明,延长硅烷化反应时间,NR混炼胶的门尼黏度增大,填料的分散性能提高,硫化速率加快。相同反应时间下,采用密炼机保温试样的硫化速率高于采用烘箱保温的试样。延长硅烷化反应时间,NR硫化胶的定伸应力提高,扯断伸长率及撕裂强度略有下降。采用密炼机保温5 min的试样压缩生热最少,滚动阻力最低。 相似文献
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研究促进剂DPG在白炭黑填充天然橡胶胶料混炼中加料顺序对胶料性能的影响。结果表明:促进剂DPG与NR、白炭黑和硅烷偶联剂同时加入混炼能够参与和促进硅烷化反应,改善白炭黑与NR之间的相容性,减轻白炭黑聚集,因此可降低Payne效应,提高胶料的耐热老化性能,但因其参与硅烷化反应而减小了参与硫化反应的量,导致硫化速率降低,焦烧时间延长,同时由于交联密度下降导致硫化胶的耐磨性能、300%定伸应力和撕裂强度降低及60 ℃时的tanδ增大,因此在配方开发和混炼工艺设计时,应考虑适量补充促进剂DPG在前期混炼阶段加入时的损耗。 相似文献
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综述白炭黑和硅烷偶联剂的特性、两者之间的化学反应机理和反应动力学以及白炭黑胶料的混炼工艺特点。白炭黑的表面积是决定其补强能力的重要因素,结构度决定了其聚集体之间的自由体积,高分散性白炭黑小聚集体尺寸占比更大,因此更有利于分散;白炭黑絮凝对最终产品的性能和加工过程都有不良影响,提高白炭黑的硅烷化效率是降低絮凝的有效方法;白炭黑表面大量的极性羟基导致其与非极性橡胶相容性差,硅烷偶联剂的偶联作用使白炭黑的补强效果显著提高,硅烷的吸附能力是硅烷化反应速率的决定性因素,烷基链的空间位阻效应在硅烷化反应和硫化反应中起着重要作用,含长链取代基以及巯基硅烷等新型偶联剂能获得更高的白炭黑分散性;采用啮合型密炼机、提高排胶温度、降低冷却温度、减小填充系数、使用空气注射均有利于提高白炭黑的硅烷化效率。 相似文献
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通过控制混炼工艺研究了温度对Si-69原位改性白炭黑填充天然橡胶(NR)硅烷化反应的影响,利用硫化仪、橡胶加工分析仪、核磁共振交联密度仪以及全反射红外光谱仪等对白炭黑的填料网络结构及与NR的相互作用进行了分析。结果表明,在混炼时间一定的条件下,较高的混炼温度(150℃)有利于白炭黑与Si-69的硅烷化反应,NR混炼胶的Payne效应较弱,白炭黑在橡胶基质中的填料网络化结构也较弱,白炭黑的絮凝速率较慢;NR混炼胶的物理交联密度较大,分子链运动更加受限,白炭黑与NR间的相互作用较强;此时全反射红外光谱分析结果显示白炭黑填充NR混炼胶的羟基吸收峰较小,说明白炭黑表面的羟基减少,极性减弱。 相似文献
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乙烯酮(双乙烯酮)是十分重要的化工中间体,其下游产品较多。江苏某化工厂开发生产乙烯酮(双乙烯酮)下游产品三十多个,年生产规模三万多吨,是国内以乙烯酮(双乙烯酮)为中间体生产精细化学品的综合骨干企业。针对乙烯酮(双乙烯酮)下游产品废水特点,该厂结合企业实际,开展了产品优化,结构调整,清洁生产,资源循环利用,节水降耗等工作,从源头削减了污染物的生产。同时投资二千多万元新建预处理装置三套,6000m3/d废水生化处理装置一套,使全厂乙烯酮(双乙烯酮)下游产品的废水得到了有效的治理。 相似文献
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The miscibility of various amorphous polybutadienes with mixed microstructures of 1,4 addition units (cis, 1,4 and trans 1,4) and 1,2 addition units have been investigated. The studies here involved optical transparency, differential scanning calorimetry, and small angle light scattering. It was found that a 90 percent (cis) 1, 4 addition polybutadiene was immiscible with high (91 percent) 1,2 addition polybutadiene. Reduction of the 1,2 content to 71 percent induced an upper critical solution temperature (UCST) with the cis 1,4 polymer. Polybutadienes with 50 percent and 10 percent 1,2 contents were miscible above the crystalline melting temperature of the cis 1,4 polybutadiene. Immiscibility of the 91 percent 1,2 addition polymer was also found with a 10 percent 1,2 polybutadiene. The latter polymer also exhibits an UCST with the 71 percent 1,2 polymer. The results are used to interpret the characteristics of blends of polybutadienes of varying microstructure. 相似文献
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以F类粉煤灰为例,详细介绍了测定粉煤灰中烧失量的步骤、计算数学模型、影响测量不确定度的因素以及各项测量不确定度分量评定,人员、设备、材料、方法、环境都是影响测量不确定的因素。 相似文献
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我厂3号回转窑(Φ4m×60m)生产线在1996年年底由SP窑(产量912t/d)改为NSP窑(产量1320t/d),预分解系统为四级旋风预热器带离线式分解炉 相似文献
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The objective of the study was to explore the effect of the degree of deacetylation (DD) of the chitosan used on the degradation rate and rate constant during ultrasonic degradation. Chitin was extracted from red shrimp process waste. Four different DD chitosans were prepared from chitin by alkali deacetylation. Those chitosans were degraded by ultrasonic radiation to different molecular weights. Changes of the molecular weight were determined by light scattering, and data of molecular weight changes were used to calculate the degradation rate and rate constant. The results were as follows: The molecular weight of chitosans decreased with an increasing ultrasonication time. The curves of the molecular weight versus the ultrasonication time were broken at 1‐h treatment. The degradation rate and rate constant of sonolysis decreased with an increasing ultrasonication time. This may be because the chances of being attacked by the cavitation energy increased with an increasing molecular weight species and may be because smaller molecular weight species have shorter relaxation times and, thus, can alleviate the sonication stress easier. However, the degradation rate and rate constant of sonolysis increased with an increasing DD of the chitosan used. This may be because the flexibilitier molecules of higher DD chitosans are more susceptible to the shear force of elongation flow generated by the cavitation field or due to the bond energy difference of acetamido and β‐1,4‐glucoside linkage or hydrogen bonds. Breakage of the β‐1,4‐glucoside linkage will result in lower molecular weight and an increasing reaction rate and rate constant. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3526–3531, 2003 相似文献
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