The aim of this study was to synthesize ethylene-hexene copolymers of the type LLDPE using a combination of metallocene binary catalysts (Cat 1: Cp2ZrCl2 and Cat 2: Et(IndH4)2ZrCl2), where each catalyst has different microstructural control capacities. The effect of diethyl zinc (DEZ) concentration as a chain shuttling agent (CSA) was evaluated in parameters such as catalytic activity, as well as thermal properties, comonomer content incorporated into the polymer chain, crystal structure, and also dynamic mechanical properties of the obtained copolymers. The results showed that, opposite to the behavior of the catalyst mixtures, DEZ promoted an increase in the polymerization activity with the isolated catalysts. Furthermore, CSA provided the increase of the rigid segments in the copolymer chain obtained with the binary catalyst.
[1] Makio H., Terao H., Iwashita A. and Fujita T.: Chem. Rev., 2011, 111, 2363.
[2] Mitani M., Saito J., Ishii S-I. et al.: Chem. Rec., 2004, 4,137.
[3] Qiao J., Guo M., Wang L. et al.: Polym. Chem., 2011, 8, 1611.
[4] Makio H. and Fugita T.: Accounts of Chem. Res., 2009, 42, 1532.
[5] Makio H., Kashiwa N. and Fujita T.: Adv. Synthesis & Catalysis, 2002, 344, 477.
[6] Gibson C.: Science, 2009, 312, 703.
[7] Tynys E., Eilertsen J., Seppällä J. and Rytter E.: J. Polym. Sci. A, 2007, 45, 1364.
[8] Alfano F., Boone H., Busico V. et al.: Macromolecules, 2007, 40, 7736.
[9] Shan C. and Hazlitt L.: Macromol. Symposia, 2007, 257, 80.
[10] Kuhlman R. and Wenzel T.: Macromolecules, 2008, 41, 4090.
[11] Wang H., Khariwala D., Cheung W. et al.: Macromolecules, 2008, 40, 2852.
[12] Khariwala D., Taha A., Chum S. et al.: Polymer, 2008, 49, 1365.
[13] Zinck P.: Polym. Int., 2012, 61, 2.
[14] Martins R., Quinello L., Souza G. and Marques M.: Chem.& Chem. Techn., 2012, 6, 153.
[15] Silveira F., Loureiro S., Galland G. et al.: J. Mol. Catal. A, 2003, 206, 389.
[16] Chien J., Iwamoto Y. and Rausch M.: J. Polym. Sci. A, 1999, 37, 2439.
[17] Bastos Q. and Marques M.: J. Polym. Sci. A, 2005, 43, 263.
[18] Meurs M., Britovsek G., Gibson V. and Cohen S.: J. Am. Chem. Soc., 2005, 127, 9913.
[19] Wang H., Khariwala D., Cheung W. et al.: Macromolecules, 2008, 40, 2852.
[20] Zuo F., Hsiao B., Mehta A. et al.: Macromolecules, 2010, 43, 1922.
[21] Arriola D., Carnahan E., Hustad P. et al.: Science, 2006, 312, 714.