An Investigation on Polymerization of Ethylene by Ziegler-Natta Catalyst in the Presence of a Promoter: Polymerization Behavior and Polymer Microstructure

DOI: https://doi.org/10.9767/bcrec.13.3.1574.412-419
Copyright (c) 2018 Bulletin of Chemical Reaction Engineering & Catalysis
Creative Commons License
This work is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License.
Cover Image

Article Metrics: (Click on the Metric tab below to see the detail)

Article Info
Submitted: 02-10-2017
Published: 04-12-2018
Section: Original Research Articles
Fulltext PDF Tell your colleagues Email the author

The effect of a halocarbon (ethyl chloride) as a promoter on a Ziegler-Natta catalyst composed of‌ T‌iCl4 (catalyst), AlEt3 (activator) and Mg(OEt)2 (support) in the polymerization of ethylene have been investigated. In addition, the impact of this compound on the structural and thermal properties of the produced polyethylene has been studied. The catalyst activity and polymerization rate increased almost up to twice when a suitable molar ratio of ethyl chloride to triethylaluminum (TEA) was used. There was no change in the type of the profile of the polymerization rate during the polymerization time. A reduction in the polymer molecular weight was observed in the presence of the promoter and hydrogen. In addition, the MWD curve shifted toward lower values in the presence of ethyl chloride. Furthermore, a numerical method was used to obtain the most probable chain-length distribution, number   average molecular weight and weight fraction corresponding to each site type in the presence and absence of the promoter. Since, the catalyst had an irregular shape, the produced polymer also showed a similar morphology. In addition, the promoter used in the polymerization did not have any effect on the produced polymer morphology. The DSC results indicated that the presence of the promoter in the polymerization led to a decrease in the melting point of the produced polymer; whereas, there were no remarkable changes in the crystallization temperature of the polymers. Copyright © 2018 BCREC Group. All rights reserved

Received: 2nd October 2017; Revised: 5th April 2018; Accepted: 26th April 2018

How to Cite: Gholami, Y., Abdouss, M., Abedi, S., Azadi, F., Baniani, P., Arsalanfar, M. (2018). An Investigation on Polymerization of Ethylene by Ziegler-Natta Catalyst in the Presence of a Promoter: Polymerization Behavior and Polymer Microstructure. Bulletin of Chemical Reaction Engineering & Catalysis, 13 (3): 412-419 (doi:10.9767/bcrec.13.3.1574.412-419)

Permalink/DOI: https://doi.org/10.9767/bcrec.13.3.1574.412-419

  

Keywords

Halocarbon; Polymerization; Polyethylene; Promoter; Ziegler-Natta Catalyst

  1. Yaghoob Gholami 
    Department of Chemistry, Amirkabir University of Technology , Hafez Ave, Tehran, Iran, Islamic Republic of
  2. Majid Abdouss 
    Department of Chemistry, Amirkabir University of Technology , Hafez Ave, Tehran, Iran, Islamic Republic of
  3. Sadegh Abedi 
    Petrochemical R&T Company of NPC (Tehran Center), Iranian Institute of Polymer and Petrochemical Research , Pajouhesh Blvd., Karaj Highway, Tehran, Iran, Islamic Republic of
  4. Farhad Azadi 
    Petrochemical R&T Company of NPC (Tehran Center), Iranian Institute of Polymer and Petrochemical Research , Pajouhesh Blvd., Karaj Highway, Tehran, Iran, Islamic Republic of
  5. Pezhman Baniani 
    Petrochemical R&T Company of NPC (Tehran Center), Iranian Institute of Polymer and Petrochemical Research , Pajouhesh Blvd., Karaj Highway, Tehran, Iran, Islamic Republic of
  6. Maryam Arsalanfar 
    Department of Chemistry, Amirkabir University of Technology , Hafez Ave, Tehran, Iran, Islamic Republic of
  1. Chien, J.C.W., Nozaki, T. (1991). High Activity Magnesium Chloride Supported Catalysts for Olefin Polymerization. XXIX. Molecular Basis of Hydrogen Activation of Magnesium Chloride Supported Ziegler–Natta Catalysts. J. Polym. Sci. Pol. Chem., 29: 505-514.
  2. Abedi, S., Hassanpour, N. (2006). Prepration of Bimodal Polypropylene in Two-Step Poly-merization. J. Appl. Polym. Sci., 101: 1456-1462.
  3. Nikolaeva, M.I., Mikenas, T.B., Matsko, M.A., Echevskaya, L.G., Zakharov, V.A. (2011). Ethylene Polymerization over Supported Titanium‐Magnesium Catalysts: Effect of Polymerization Parameters on the Molecular Weight Distribution of Polyethylene. J. Appl. Polym. Sci., 122: 3092-3101.
  4. Czaja, K., Białek, M., (2001). Effect of Hydrogen on the Ethylene Polymerization Process over Ziegler–Natta Catalysts Supported on MgCl2(THF)2. II. Kinetic Studies. J. Appl. Polym. Sci., 79: 361-365.
  5. Mazaherian, M., Dashti, A., Mortazavi, M.M., Ahmadjo, S. (2015). Effect of Halocarbon as Promoter on Activity of Ziegler-Natta Catalyst in 1-Hexene Polymerization, The 9 th International Chemical Engineering Congress & Exhibition (IChEC 2015). 12-26.
  6. Winslow, L.N., Klendworth, D.D., Menon, R., Lynch, M.W., Fields, G.L., Johnson, K.W., (1996). Vanadium-containing Catalyst System. US5534472 A.
  7. Luo, H.K., Tang, R.G., Yang, H., Zhao Q.F., An, J.Y. (2000). Studies on Highly Efficient Promoters for Titanium-based Ziegler–Natta Catalyst for Ethylene Polymerization. Appl. Catal. A Gen., 203: 269-273.
  8. Adisson, E., Deffieux, A., Fontanille, M., Bujadoux, K. (1994). Polymerization of Ethylene at High Temperature by Vanadium-based Heterogeneous Ziegler-Natta Catalysts. II. Study of the Activation by Halocarbons. J. Polym. Sci. Pol. Chem., 32: 1033-1041
  9. Yang, Y., Kim, H., Lee, J., Paik, H., Jang, H. (2000). Roles of Chloro Compound in Homogeneous [Cr(2-Ethylhexanoate)3/2,5-Dimethylpyrrole / Triethylaluminum / Chloro Compound] Catalyst System for Ethylene Trimerization. Appl. Catal. A Gen., 193: 29-38.
  10. Luo, H.K., Tang, R.G., Gao, K.J. (2002). Studies on the Formation of New, Highly Active Silica-Supported Ziegler–Natta Catalyst for Ethylene Polymerization. J. Catal., 210: 328-339.
  11. Bahri-Laleh, N., Arabi, H., Mehdipor-Ataei, S., Nekoomanesh-Haghighi, M., Zohuri, G., Seifali, M., Akbari, Z. (2012). Activation of Ziegler‐Natta Catalysts by Organohalide Promoters: A Combined Experimental and Density Functional Theory Study. J. Appl. Polym. Sci., 123: 2526-2533.
  12. Bohm, L. (1997). Process for the Preparation of a Poly-1-olefin. US5648309 A.
  13. Kang, K.K., Shiono, T., Jeong, Y.T., Lee, D.H. (1999). Polymerization of Propylene by using MG(OEt)2–DNBP–TiCl4 Catalyst with Alkoxy Disilanes as External Donor. J. Appl. Polym. Sci., 71: 293-301.
  14. Vogel, A.L., Bassett, J. (1978). Vogel's Textbook of Quantitative Inorganic Analysis : Including Elementary Instrumental Analysis. Longman, London, New York.
  15. Kashiwa, N., Yoshitake, J. (1984). The Influence of the Valence State of Titanium in MgCl2‐supported Titanium Catalysts on Olefin Polymerization. Die Makromolekulare Chemie, 185: 1133-1138.
  16. Inoue, M. (1963). Studies on Crystallization of High Polymers by Differential Thermal Analysis. J. Polym. Sci. A Gen., 1: 2697-2709.
  17. Salajka, Z., Kratochvíla, J., Hudec, P., Vĕcorek, P. (1993). One‐phase Supported Titanium‐Based Catalysts for Polymerization of Ethylene. II. Effect of Hydrogen. J. Polym. Sci. Pol. Chem., 31: 1493-1498.
  18. Soares, J.B.P., Hamielec, A.E., (1995). Deconvolution of Chain-Length Distributions of Linear Polymers Made by Multiple-Site-Type Catalysts. Polym., 36: 2257-2263.
  19. Ribeiro, M.R, Deffieux, A., Fontanille, M., Portela, M.F. (1995). Homo and Copolymerization of Ethylene: Improvement of Supported Vanadium Catalysts Performance by Halocarbons. Macromol. Chem. Phys., 196: 3833-3844.
  20. Ghafelebashi Zarand, S.M.; Mortazavi, S.M.M., Najafi, M., Haddadi-Asl, V. (2012). Effects of Temperature and Cocatalyst Concentration on the Number of Active Sites in a TiCl4/Mg(OEt)2 Catalyst for Ethylene Polymerization. J. Petrol. Sci. Technol., 2: 12-16.
  21. Richards, R.B. (1951).Polyethylene‐structure, Crystallinity and Properties. J. Appl. Chem., 1: 370-376.