Linear Low Density Polyethylene Production by Tandem Polymerization of Ethylene: Properties and Applications

Document Type : compile

Authors

1 MSc student, Institute for Advanced Studies in Basic Sciences (IASBS)

2 Academic Staff, Institute for Advanced Studies in Basic Sciences (IASBS)

Abstract

Linear low density polyethylene (LLDPE) is a linear polyethylene with considerable number of short branches that is produced by the copolymerization of ethylene with α-olefins such as 1-butene, 1-hexene and 1-octene. LLDPE has higher tensile strength and higher impact resistance than LDPE. It is very flexible and elongates under stress. It can be used to make thinner films, with better environmental stress cracking resistance. It is an important family of polyolefins, which has been widely used as thermoplastic polymers because of their combined stiffness and stress-crack resistance. Commonly, LLDPE is produced through a two-stage process including comonomer and copolymer formation in two separate reactors; though an alternative LLDPE preparation method that has attracted good attention among academic and industrial producers is tandem polymerization where one catalyst produces α-olefin in situ and another copolymerizes ethylene and α-olefin monomers. Compared to the commonly used two-stage processes, single-stage approach has a clear advantage in plant investment, α-olefin purification, storage, transport and reducing operational unit. Furthermore in tandem systems, the reactivity of the active sites must be well matched so that the product of one cycle does not overwhelm the overall tandem sequence. In this paper, a historical overview is provided on the developments in LLDPE production through tandem polymerization of ethylene.

Keywords

Main Subjects

References

1.Meyer T.H. and Keurentjez J., Handnook of Polymer Reaction Engineering, An Integrated Approach, Wiley-VCH, Weinheim,1-15, 2005.
2.Handbook of Thermoplastics, Olagoke O. and Adewale K. (Eds.), Vol. 41, CRC, Taylor and Francis, Boca Raton, 2016.
3.Griffith J.H. and Runby B.G., Dilatometric Measurments on Poly(4-methyl-1-1-pentene) Glass and Melt Transition Temperatures,Crystallization Rates, and Unusual Density Behavior,J. Polym. Sci., 44, 369-381, 1960.
4.Komon Z.J.A. and Bazan G.C., Synthesis of Branched Polyethyleneby Tandem Catalysis, Macromol. Rapid Commun., 22, 467-478, 2001.
5.Manyik R.M., Walker W.E., and Wilsin T.P., A Soluble Chromium-based Catalyst for Ethylene Trimerization and Polymerization,J. Catal., 47, 197-202, 1977.
6.Bianchini C., Miller H., and Ciardelli F., Combinations of Transition Metal Catalysts for Reactor Blending; Modification
and Blending of Synthetic and Natural Macromolecules, Ciardelli F., Penczek S. (Eds.), NATO Science Series, Vol.175, Springer, Dordrecht, 2004.
7.Bensason S., Minick J., Moet A., Chum S., Hiltner A., and Baer E., Classification of Homogeneous Ethylene-Octene CopolymersBased on Comonomer Content, J. Polym. Sci., Part B: Polym. Phys., 34, 1301-1315, 1996.
8.Liu S.H., Motta A., Delferro M., and Marks T.J., Synthesis, Characterization, and Heterobimetallic Cooperation in a Titanium-chromium Catalyst for Highly Branched Polyethylenes, J. Am. Chem. Soc., 135, 8030-8033, 2013.
9.Furlan L.G., Kunrath F.A., Mauler R.S., Souza R.F., and Casagrande O.L., Linear Low Density Polyethylene (LLDPE)from Ethylene Using TpMsNiCl (TpMs=hydridotris(3-mesitylpyrazol-1-yl)) and Cp2ZrCl2 as a Tandem Catalyst System, J. Mol. Catal. A: Chem., 214, 207-211, 2004.
10.Bianchini C., Frediani M., Giambastiani G., Kaminsky W., Meli A., and Passaglia E., Amorphous Polyethylene by Tandem
Action of Cobalt and Titanium Single-site Catalysts, Macromol. Rapid Commun., 26, 1218-1223, 2005.
11.Kuhn M.C.A., Silva J.L., Casargrande A.C.A., Mauler R.S., and Casagrande O.L., Tandem Action of TpMsNiCl and supportedCp2ZrCl2 Catalysts for the Production of Linear Low Density Polyethylene, Macromol. Chem. Phys., 207, 827-835, 2006.
12.Zhang J., Fan H., Li B., and Zhu S., Effect of Catalysts Supportingon Tandem Polymerization of Ethylene Stock in Synthesisof Ethylene-1-hexene Copolymer, Ind. Eng. Chem. Res., 47, 5369-5375, 2008.
13.Jiang T., Huang Z., Luo M., Chen H., and Ning Y., Preparation of Ethylene/1-octene Copolymers from Ethylene Stock with Tandem Catalytic System, J. Appl. Polym. Sci., 107, 3071-3075, 2008.
14.Guo S., Fan H., Bu Z., Li B., and Zhu S., Tandem Action of SNS-Cr and CGC-Ti in Preparation of Ethylene-1-hexene Copolymersfrom Ethylene Feedstock, Macromol. Chem. Phys., 215, 1661-1667, 2014.
15.Mohamadnia Z., Ahmadi E., Nekoomanesh Haghighi M., Farandpour A., Rezazadeh Z., and Fallahi M., Preparation of LLDPE Through Tandem Ethylene Polymerization Using Chromium and Zirconium Catalysts, Iran. Polym. J., 24, 621-628, 2015.
16.Pinheiro A.C., Casagrande A.C., and Csagrande O.L., Linear Low-density Polyethylene Nanocomposites by in situ PolymerizationUsing a Zirconium-nickel Tandem Catalyst System, J. Polym. Sci. Part A: Polym. Chem., 52, 3506-3512, 2014.
Basparesh
Volume 7, Issue 3 - Serial Number 24
December 2017
Pages 16-25

Files

Share

How to cite

Statistics