Improving Impact Poly(propylene) Morphology and Production: Selective Poisoning of Catalyst Surface Sites and the Use of Antistatic Agents
Improving Impact Poly(propylene) Morphology and Production: Selective Poisoning of Catalyst Surface Sites and the Use of Antistatic Agents
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DOI：
10.1002/macp.200500379
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发表时间：
2006-01
影响因子：
2.5
通讯作者：
D. Bouzid;T. McKenna
中科院分区：
文献类型：
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作者：
D. Bouzid;T. McKenna
选择性中毒是一种改善高抗冲聚丙烯共聚物粒子形态和流变性的方法。为了在不影响反应动力学的情况下避免乙丙橡胶(EPR)的积聚，对催化剂表面进行了两种不同的中毒方法：在均聚合和共聚反应步骤之间使用乙二醇二甲醚的浆相中毒步骤；以及在气相共聚反应器中使用商用抗静电剂直接中毒。观察到，两种方法都消除了颗粒表面橡胶的形成，对动力学没有明显的影响。另一方面，在气相反应中直接使用产物也有助于减少静电。从这些实验中可以得出结论，工业抗静电剂的作用至少有一部分来自催化剂表面活性中心的中毒。此外，似乎在本研究中使用的催化剂的情况下，EPR似乎没有从不断增长的颗粒中流出。在颗粒表面发现的大部分EPR都是在它附近形成的。
Selective poisoning has been studied as a means of improving the morphology and rheological properties of high-impact poly(propylene) copolymer particles. Two different methods of poisoning the catalyst surface in order to avoid the accumulation of ethylene-propylene rubber (EPR) without influencing the reaction kinetics were tested: a slurry-phase poisoning step using ethylene glycol dimethyl ether between the homopolymerisation and copolymerisation reaction steps; and direct poisoning via the use of a commercial antistatic agent during the gas-phase copolymerisation reactor. It was observed that both methods eliminated the formation of rubber on the particle surface without noticeably influencing the kinetics. On the other hand, the use of the products directly in the gas-phase reaction also contributed to the reduction of static electricity. It can be concluded from these experiments that industrial antistatic agents derive at least part of their effect from poisoning of the active sites on the surface of the catalyst. Furthermore, it appears that in the case of the catalyst used in this study, EPR does not appear to flow out of the growing particles. Most of the EPR found at the surface of the particles is formed close to it.