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首页> 外文会议>American Institute of Chemical Engineers Annual Meeting >On the Injection of Initiator as Bubbles in Helical Ribbon Agitated CSTR During Continuous Mass Polymerization ABS
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On the Injection of Initiator as Bubbles in Helical Ribbon Agitated CSTR During Continuous Mass Polymerization ABS

机译：在连续质量聚合ABS中注射引发剂作为螺旋色带搅拌Cstr的气泡

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Polybutadiene was dissolved in a feed stream of styrene, acrylonitrile, and methyl ethyl ketone to form a feed mixture. The mixture was polymerized in a continuous process under agitation using the Monsanto two continuous stirred tank reactor in series process. The polymerization occurred in a two stage reactor system over an increasing temperature profile. During the polymerization process, some of the forming copolymer grafts to the rubber particles while some of it does not graft, but, instead, forms matrix copolymer. The resulting polymerization product was then devolatilized, extruded, and pelletized. The peroxy initiators are used to initiate the free radical chain polymerization reactions. These have been found to yield better results in terms of the degree of grafting and desired molecular weight etc. The first reactor is agitated using a close clearance helical ribbon agitator. For the same power draw the HRA provides a better degree of agitation and flow throughput with a circulation pattern with flow of fluid down the wall and up at the central axis. The mixing time in this reactor is given as a constant times the agitator RPM. For a CSTR at 35 RPM the mixing time can be taken as 4 minutes. The half-life of the initiators can be less than the mixing time can cause non-uniform grafting. So initiators with higher half-lives are selected. In any case the initiator can be introduced in the reactor as a bubble train at a frequency of 2.5 Hz. For example whtn the bubble diameter is 2 cm. and for a initiator half-life of 7 minutes the interfacial area of the bubbles at the half-way point was calculated. At a feed rate of 45.5 kg/hr with a monomer concentration of 20 kg/hr and a conversion level of 15% what the mass transfer rate of the initiator to the graft phase was found to be 0.21 mol/m^2/s.
机译：将聚丁二烯溶解在苯乙烯，丙烯腈和甲基乙基酮的进料流中以形成饲料混合物。将混合物在搅拌下在连续过程中使用串联工艺中的晶颗连续搅拌罐反应器进行聚合。聚合在两个阶段反应器系统中发生在增加的温度曲线上。在聚合过程中，一些成形共聚物移植到橡胶颗粒中，而其中一些不会移植物，而是形成基质共聚物。然后将所得聚合产物脱挥发，挤出和造粒。过氧引发剂用于引发自由基链聚合反应。已经发现这些在接枝和所需的分子量方面产生更好的结果。使用近距离螺旋带搅拌器搅拌第一反应器。对于相同的功率，绘制HRA提供更好程度的搅拌和流量，具有循环模式，流体流动，壁向上处于中心轴线。将该反应器中的混合时间作为搅拌器RPM的恒定时间给出。对于35rpm的CSTR，可以将混合时间作为4分钟。引发剂的半衰期可以小于混合时间会导致不均匀的嫁接。所以选择了较高半衰期的启动器。在任何情况下，发起者都可以以2.5Hz的频率作为气泡列车在反应器中引入。例如气泡直径为2cm。对于启动器半衰期为7分钟的半衰期，计算了半路点的气泡的界面区域。以45.5kg / hr的进料速率，单体浓度为20kg / hr，转化率为15％的引发剂与移植物相的传质速率为0.21mol / m ^ 2 / s。

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