Modeling and kinetics of tandem polymerization of ethylene catalyzed by bis(2-dodecylsulfanyl-ethyl)amine-CrCl3 and Et(Ind)(2)ZrCl2

作者：Zhang Junwei; Fan Hong^*; Li Bo Geng; Zhu Shiping

来源：Chemical Engineering Science, 2008, 63(8): 2057-2065.

DOI：10.1016/j.ces.2007.12.032

• ethylene-1-hexene copolymer
• ethylene trimerization
• tandem catalysis system
• LLDPE
• modeling

A mathematical model was developed to describe ethylene-1-hexene copolymerization with a tandem catalysis system. A series of semibatch polymerization runs catalyzed by a trimerization catalyst bis(2-dodecylsulfanyi-ethyl)amine-CrCl3 and a copolymerization catalyst Et(Ind)(2)ZrCl2 in toluene at 74 degrees C were carried out to verify the model. Both experimentation and modeling showed that adjusting the Cr/Zr ratio yielded various branching densities and thus melting temperatures, as well as molecular weights and polydispersities. Broad composition distributions and thus broad DSC curves were observed at high Cr/Zr ratios. Modeling results elucidated that this is due to an accumulation of I-hexene component and to composition drifting during the copolymerization. It was also found that applying a short time period of pre-trimerization improved homogeneity in chain microstructure and minimized broadening in DSC curves.

• 出版日期2008-4
• 单位浙江大学