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RAFT法制备高分子量窄分布的PS聚合物 总被引:1,自引:0,他引:1
以二硫代枯酯(CDB)为链转移剂,AIBN作为引发剂,用可逆加成-断裂链转移(RAFT)活性自由基聚合方法制备了高分子量窄分布的PS聚合物,其重均分子量可达到-Mw=465 000 g/mol,数均分子量达到-Mn=333 000 g/mol,分布指数D=1.40。考察了链转移剂浓度、聚合温度和聚合时间对PS聚合物的分布指数和分子量的影响,此方法制得的PS聚合物能满足工程材料的要求。 相似文献
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闭式冷却塔采用水蒸发时吸热、再由冷却液冷却的原理。喷淋循环水(冷却水)储存在闭式冷却塔的底部,工作流体(软化水或其他液体)在闭式冷却塔的冷却盘管中循环。喷淋水由喷淋系统泵通过配水系统和喷淋喷嘴喷淋在盘管表面,降低管道内工作流体的温度。在实际运行过程中,由于喷淋水(冷却水)为深井水,盐含量、硬度、碱度及硫酸根含量较高,经蒸发浓缩后,喷淋循环水水质恶化,出现严重结垢的现象,严重影响生产装置的安全平稳运行。形成的水垢主要以硫酸钙为主,清洗及清除难度较大,且频繁的清洗对设备也造成了一定的损伤。基于补水水质数据及运行工况条件,对结垢的原因和机理进行了分析讨论,筛选具有针对性的水质稳定处理剂,进行有效的水质稳定处理,加强水质检测管理,制定合理的水质控制指标,定期对填料进行人工清理,确保通风口通畅。经过上述处理后,闭式冷却塔喷淋循环水水质明显好转。浓缩倍数由原来的30倍降到了8倍;循环水Ca2++碱度为从3 820 mg/L降至1 773 mg/L;硫酸钙的LSI指数从3.8降到了2.3;换热盘滚较为干净,无明显水垢产生;循环水总铁为0.037 mg/L,远低于国家标准要求的小于2.0 mg/L,即通过有效的水质稳定处理,喷淋循环水系统结垢和腐蚀的趋势均得到了有效的控制,提高了喷淋装置的换热效率,为循环水系统的长周期平稳运行创造了有利的条件。 相似文献
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In this study,based on the actual operating conditions of the cooling water treatment device of the associated gas recovery device and the water quality conditions of the supplement water,the water quality stability index calculation and water quality control model were constructed,and the software system for water treatment dosing process detection and remote data transmission service of water treatment equipment were developed,which were integrated with the hardware to form the water quality stability treatment device of the circulating water system.The application results in Zhuangyilian Light Hydrocarbon Plant showed that the qualified rate of water quality in water treatment plant was significantly improved,reaching 90%.
The concentration multiple of the circulating water system increased from 3 times to 10 times,with an increase of 200%.The sewage discharge amount of circulating water decreased by 80%.The trend of scaling and corrosion of water quality has been effectively controlled and alleviated,and there are no obvious scaling phenomenon in cooling water tower and heat-exchange equipment.The stable treatment of circulating water can realize "unattended operation". 相似文献
The concentration multiple of the circulating water system increased from 3 times to 10 times,with an increase of 200%.The sewage discharge amount of circulating water decreased by 80%.The trend of scaling and corrosion of water quality has been effectively controlled and alleviated,and there are no obvious scaling phenomenon in cooling water tower and heat-exchange equipment.The stable treatment of circulating water can realize "unattended operation". 相似文献
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将1-烯丙氧基-2,3-环氧丙烷、1,3,5,7-四甲基环四硅氧烷和乙烯基三乙氧基硅烷合成了增黏剂DAVE,以不同端乙烯基硅油、不同质量比配合使用,与含氢硅油发生加成反应,添加乙炔基环己醇、A-171以延长贮存稳定性,从而制备了粘结性单组分硅橡胶密封材料。主要研究了基础胶各组分、增黏剂DAVE等对密封材料性能的影响。结果表明,黏度19mPa·s与3000mPa·s的端乙烯基硅油以质量比8:100复配作基础聚合物,添加活性氢质量分数为0.8%的含氢硅油,使摩尔比n(Si-H)/n(Si-Vi)为1.2,抑制剂适宜的用量为0.003%,DAVE用量为2%,密封材料具有最佳综合性能。 相似文献
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