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为了考察制备过程中产生的游离铁离子对苯乙烯-丁二烯-苯乙烯嵌段共聚物(SBS)热氧老化性能的影响,制备了不同铁含量的SBS试样,并采用差示扫描量热法、全反射傅里叶变换红外光谱及热空气加速老化实验方法分析了不同铁离子对SBS热氧老化过程的影响规律。结果表明,随着体系中铁离子含量的增加,SBS试样出现老化交联吸热峰的温度降低,且交联峰面积增大;随着热氧老化的进行,SBS中形成了含有羰基的酮和醛类结构,转化率呈"S"型趋势增加,且随着铁离子含量升高,SBS分子结构中亚甲基、乙烯基、1,4-双键的含量依次降低,转化率升高,热氧老化程度增大,说明铁离子加速SBS热氧老化的过程明显。推断其作用机理为在热氧氧化初期,铁离子引入的更多的氧首先进攻亚甲基上的α-H,产生游离自由基,并进一步攻击不饱和双键,从而引发SBS产生不同程度的交联和降解。 相似文献
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焦油产量是影响苯乙烯装置物耗的主要因素,分析焦油组成得出,降低焦油产量应从降低焦油中苯乙烯含量及降低装置聚合物生成量着手。薄膜蒸发器控制温度、T4003塔釜温度、焦油循环比与系统阻聚剂含量是影响装置焦油产量的主要影响因素。薄膜蒸发器控制温度、T4003塔釜温度,主要影响焦油中苯乙烯含量,通过建立物料组成与温度的拟合关系式,结合生产的实际情况,摸索出薄膜蒸发器控制温度的适宜范围为116~122℃,薄膜蒸发器进料中苯乙烯含量控制的适宜范围为33%~39%,T4003塔釜温度控制的适宜范围为85.5~89℃,此时焦油苯乙烯含量能降低至8%左右,焦油仍保持较好的流动性。焦油循环比与系统阻聚剂含量主要影响系统聚合物含量。根据装置实际运行情况,确定了焦油循环比与系统阻聚剂含量的工艺调整思路,达到了降低装置物耗的目的,提高了装置精细化操作水平。 相似文献
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苯乙烯在特定条件下是一种极易自聚的有机化合物,为从根本上解决苯乙烯产品储罐聚合物含量超标的问题,从工艺流程、安全监测、设备选型等方面对苯乙烯储存设施进行分析和设计. 相似文献
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车身涂装质量除直接影响汽车的防锈蚀性能、外观性能,还影响其制造成本。因此,对汽车涂装质量进行检验是汽车检验中一项重要内容。本文全面介绍了汽车涂装质量的检测方法;车身电泳漆膜现场常用的质量检测方法;车身中涂和面漆涂膜现场常用的质量检测方法;以及新车、在用车及乘用车车身涂装后的检验方法。 相似文献
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Emma L. Bradley Laurence Castle Andrew P. Damant Sue M. Jickells Mark R. Philo 《Journal of Coatings Technology and Research》2010,7(4):477-483
Glass–fiber-reinforced plastic (GRP) vats are used widely for the storage of foodstuffs and potable water. As the inner surfaces
deteriorate during decades of use, they need to be repaired. The unsaturated polyester resins that are used for recoating
are crosslinked with styrene which can cause taint and odor problems. This article describes some coating parameters that
affect the content of residual styrene and its subsequent migration. The influences of cure temperature and duration, along
with the effect of washing with warm detergent solution, were investigated. Cured specimens were tested for their residual
styrene content and for styrene migration into the food simulants, distilled water, 3% acetic acid, and 15% ethanol. The dominant
factor in reducing the amount of residual styrene is the temperature. The resin self-heats as it cures, typically up to 50°C.
Thus, any further lowering of the styrene content requires a higher cure temperature than this. A 3-h cure at 80°C reduced
both the residual content and the migration levels by about 100-fold. At lower cure temperatures, the heating effect of washing
at 60°C is more important than the washing effect of the detergent. When less catalyst was used the residual styrene levels
rose dramatically, from 70 to 360 to 1300 mg/kg for the normal dose, half and quarter the normal dose, respectively. There
was a linear relationship between residual content in the GRP and the migration levels. This correlation could be used for
monitoring the quality of vats repaired in situ, using styrene-based coating resins. 相似文献
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以氧化硅玻璃纤维为载体,采用非均匀成核法制备了ATO包覆导电纤维.正交实验结果表明:影响ATO包覆纤维效果的因素依次是:包覆悬浮液中被包覆物固含量、包覆层溶液离子浓度、反应过程的pH值、包覆时反应温度及包覆离子溶液加入速度.通过正交实验所确定的ATO包覆氧化硅纤维的合理工艺参数为:悬浮液中氧化硅纤维的浓度保持在0.4 g/mL、包覆溶液的pH值控制在2.0左右、包覆层离子浓度选取0.6 mol/L、包覆离子溶液加入速度定为0.5 mL/min、反应温度为50℃.另外,对各工艺参数对导电纤维包覆的影响进行了理论分析. 相似文献
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本文主要阐述了性能优良、应用广泛的复合型环氧树脂粘合剂,在化工贮罐、防腐涂层的工艺和方法。这种粘合剂对金属有很好的粘合力,因此,应用在化工贮罐防腐方面是行之有效的方法之一。 相似文献
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Several kinds of conductive coating films were prepared from a low-density indium(III) oxide powder (which was employed because it provides a much higher volume for the same weight) and polymer latexes. The low-density In2O3, which is an electrically conductive pigment, was prepared by pyrolysis followed by the combustion of water-swellable polymer microspheres imbibed with In(NO3)3, the precursor of In2O3. Either acrylamide/N,N'-methylenebisacrylamide or poly(vinylalcohol)/glutaricdialdehyde was used to generate spherical hydrogel particles. The polymer latexes with which the In2O3 was mixed had a soft core and a hard shell structure to ensure that the coating film has suitable mechanical properties in addition to conductivity. Acrylonitrile/butadiene/styrene copolymer ABS or acrylonitrile/butylacrylate/styrene copolymer ABAS latexes were used as binders for the conductive pigment. The powder coating followed by hot pressing, the water-borne coating consisting of low-density In2O3 and polymer latexes followed by curing, or the colloidal dispersion coating was used to deposit flexible conductive coating films on polyester sheets. The conductive pigment density and the polymer latexes' size and flowability are the factors that affect the characteristics of the film. We found that the colloidal suspension coating procedure based on ABAS latexes achieves better electrical and mechanical properties for the coating films. © 1996 John Wiley & Sons, Inc. 相似文献
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聚苯胺被认为是最有应用前景的导电聚合物,目前被广泛应用在涂料、传感器、电极及电磁屏蔽等领域,而其在防腐涂层中的应用是目前研究的热点。综述了聚苯胺纳米结构的制备及其在防腐涂层中的应用,并归类总结了目前对聚苯胺防腐机理的推测与研究进展。 相似文献
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随着现代石化行业的高速发展,丁二烯产品成为石油化工领域的重要中间产品,作为一种重要的化工原料,可作为单体用于制造合成橡胶(丁苯橡胶、顺丁橡胶、丁腈橡胶、氯丁橡胶),其中丁二烯中微量水含量控制作为决定丁二烯合格与否的重要指标,丁二烯产品中水分会对聚合工艺产生影响,丁二烯聚合中水分产生静电离子致使聚合物被容器、管道壁吸附,发生堵塞现象,成为聚合工艺过程中一个重要的问题。以卡尔?费休库仑法为主,总结测定丁二烯水分的影响因素,便于提高分析准确度。 相似文献