Interplay of reversible chain transfer and comonomer incorporation reactions in coordination copolymerization of ethylene/1–hexene

Document Type : Original research


1 Department of Polymer Engineering and Color Technology, Amirkabir University of Technology, Tehran, Iran

2 Engineering Department, Catalyst Group, Iran Polymer and Petrochemical Institute, Tehran, Iran.

3 Department of Polymer Engineering, Faculty of Engineering, Qom University of Technology, Qom, Iran.

4 4Institute of Physical Chemistry, Johannes Gutenberg-Universität Mainz, Duesbergweg 10-14, D-55128 Mainz, Germany


Coordinative chain transfer polymerization (CCTP) has opened a new path for the development of novel products like olefin block copolymers and chain-end functional polyolefins. However, conflicting results are frequently reported on the catalyst performance including activity and comonomer selectivity under CCTP conditions. Here we have selected two catalysts including rac-ethylenebis(1-η5-indenyl)zirconocene and bis(imino) pyridine iron, with drastically different comonomer affinities. The effect of diethyl zinc as the chain transfer agent (CTA) on their individual performances is evaluated at different 1–hexene concentrations, in copolymerization with ethylene. Combined thermal fractionation and GPC results confirm that not all chains experience the reversible transfer reaction. Nevertheless, the metallocene catalyst shows twice activity and about 30% lower comonomer incorporation in the presence of CTA. Conversely, the late transition metal catalyst demonstrates lower activity and remains comonomer irresponsive. It could be concluded that, in addition to establishing a reversible transfer reaction, CTA affects the nature of active centers. This finding can help designing olefin copolymers with a more defined chemical composition based on CCTP reaction.


Main Subjects

  1. Domski GJ, Rose JM, Coates GW, Bolig AD, Brookhart M (2007) Living alkene polymeriza­tion: New methods for the precision synthesis of polyolefins. Prog polym Sci 32: 30-92
  2. Makio H, Terao H, Iwashita A, Fujita T (2011) FI catalysts for olefin polymerization- A compre­hensive treatment. Chem Rev 111: 2363-2449
  3. Rouholahnejad F, Mathis D, Chen P (2009) Nar­rowly distributed polyethylene via reversible chain transfer to aluminum by a sterically hin­dered zirconocene/MAO. Organometallics 29: 294-302
  4. Valente A, Mortreux A, Visseaux M, Zinck P (2013) Coordinative chain transfer polymeriza­tion. Chem Rev 113: 3836-3857
  5. Britovsek GJ, Cohen SA, Gibson VC, Maddox PJ, van Meurs M (2002) Iron-catalyzed polyeth­ylene chain growth on zinc: Linear α-olefins with a Poisson distribution. Angew Chem Int Ed 41: 489-491
  6. Britovsek G, Cohen SA, Gibson VC, van Meurs M (2004) Iron catalyzed polyethylene chain growth on zinc: A study of the factors delineating chain transfer versus catalyzed chain growth in zinc and related metal alkyl systems. J Am Chem Soc 126: 10701-10712
  7. Arriola DJ, Carnahan EM, Hustad PD, Kuhlman RL, Wenzel TT (2006) Catalytic production of olefin block copolymers via chain shuttling po­lymerization. Science 312: 714-719
  8. Auriemma F, De Rosa C, Scoti M, Di Girolamo R, Malafronte A, D’Alterio MC, Boggioni L, Losio S, Boccia AC, Tritto I (2019) Structure and mechanical properties of ethylene/1-octene multiblock copolymers from chain shuttling technology. Macromolecules:DOI:10.1021/acs. macromol.8b02470
  9. Ahmadi M, Saeb MR, Mohammadi Y, Khorasani MM, Stadler FJ (2015) A perspective on mod­eling and characterization of transformations in the blocky nature of olefin block copolymers. Ind Eng Chem Res 54: 8867-8873
  10. Mohammadi Y, Ahmadi M, Saeb MR, Khorasani MM, Yang P, Stadler FJ (2014) A detailed model on kinetics and microstructure evolution dur­ing copolymerization of ethylene and 1-octene: From coordinative chain transfer to chain shut­tling polymerization. Macromolecules 47: 4778- 4789
  11. Saeb MR, Khorasani MM, Ahmadi M, Moham­madi Y, Stadler FJ (2015) A unified picture of hard-soft segmental development along olefin chain shuttling copolymerization. Polymer 76: 245-253
  12. Shan CLP, Hazlitt LG (2007) Block index for characterizing olefin block copolymers. Macro­mol Symp 257: 80-93
  13. Wang H, Khariwala D, Cheung W, Chum S, Hilt­ner A, Baer E (2007) Characterization of some new olefinic block copolymers. Macromolecules 40: 2852-2862
  14. Briquel R, Mazzolini J, Le Bris T, Boyron O, Boisson F, Delolme F, D'Agosto F, Boisson C, Spitz R (2008) Polyethylene building blocks by catalyzed chain growth and efficient end func­tionalization strategies, including click chemis­try. Angew Chem Int Ed 47: 9311-9313
  15. German I, Kelhifi W, Norsic S, Boisson C, D'Agosto F (2013) Telechelic polyethylene from catalyzed chain-growth polymerization. Angew Chem Int Ed 52: 3438-3441
  16. Mazzolini J, Espinosa E, D'Agosto F, Boisson C (2010), Catalyzed chain growth (CCG) on a main group metal: an efficient tool to functional­ize polyethylene. Polym Chem 1: 793-800
  17. van Meurs M, Britovsek GJ, Gibson VC, Cohen SA (2005) Polyethylene chain growth on zinc catalyzed by olefin polymerization catalysts: Acomparative investigation of highly active cat­alyst systems across the transition series. J Am Chem Soc 127: 9913-9923
  18. Kuhlman RL, Wenzel TT (2008) Investigations of chain shuttling olefin polymerization using deute­rium labeling. Macromolecules 41: 4090-4094
  19. Kuhlman RL, Klosin J (2010) Tuning block compositions of polyethylene multi-block co­polymers by catalyst selection. Macromolecules 43: 7903-7904
  20. Zinck P (2016) Unexpected reactivities in chain shuttling copolymerizations. Polym Int 65: 11-15
  21. Boggioni L, Sidari D, Losio S, Stehling UM, Au­riemma F, Di Girolamo R, De Rosa C, Tritto I (2018) Ethylene–co–norbornene copolymeriza­tion in the presence of a chain transfer agent. Eur Polym J 107: 54-66
  22. Boggioni L, Sidari D, Losio S, Stehling UM, Auriemma F, Malafronte A, Di Girolamo R, De Rosa C, Tritto I (2019) Ethylene-co-norbornene copolymerization using a dual catalyst system in the presence of a chain transfer agent. Polymers 11: 554
  23. Vittoria A, Busico V, Cannavacciuolo FD, Ci­pullo R (2018) Molecular kinetic study of “chain shuttling” olefin copolymerization. ACS Catal 8: 5051-5061
  24. Zhang M, Karjala TW, Jain P (2010) Modeling of α-olefin copolymerization with chain-shuttling chemistry using dual catalysts in stirred-tank re­actors: Molecular weight distributions and copo­lymer composition. Ind Eng Chem Res 49: 8135- 8146
  25. Ahmadi M, Nasresfahani A (2015) Realistic rep­resentation of kinetics and microstructure devel­opment during chain shuttling polymerization of olefin block copolymers. Macromol Theor Simul 24: 311-321
  26. Jandaghian MH, Soleimannezhad A, Ahmadjo S, Mortazavi SMM, Ahmadi M (2018) Synthesis and characterization of isotactic poly (1-hexene)/ branched polyethylene multiblock copolymer via chain shuttling polymerization technique. Ind Eng Chem Res 57: 4807-4814
  27. Hustad PD, Kuhlman RL, Carnahan EM, Wen­zel TT, Arriola DJ (2008) An exploration of the effects of reversibility in chain transfer to metal in olefin polymerization. Macromolecules 41: 4081-4089
  28. Zhang M, Carnahan EM, Karjala TW, Jain P (2009) Theoretical analysis of the copolymer composition equation in chain shuttling copoly­merization. Macromolecules 42: 8013-8016
  29. Zhang M, Karjala TW, Jain P, Villa C (2013) The­oretical modeling of average block structure in chain-shuttling α–olefin copolymerization using dual catalysts. Macromolecules 46: 4847-4853
  30. Ribeiro R, Ruivo R, Nsiri H, Norsic SB, D’Agosto F, Perrin L, Boisson C (2016) Deci­phering the mechanism of coordinative chain transfer polymerization of ethylene using neody­mocene catalysts and dialkylmagnesium. ACS Catal 6: 851-860
  31. Bhriain NN, Brintzinger H-H, Ruchatz D, Fink G (2005) Polymeryl exchange between a nsa-zirconocene catalysts for norbornene− ethene copolymerization and aluminum or zinc alkyls. Macromolecules 38: 2056-2063
  32. Georges SB, Touré AO, Visseaux M, Zinck P (2014) Coordinative chain transfer copolymer­ization and terpolymerization of conjugated di­enes. Macromolecules 47: 4538-4547
  33. Loughmari S, Hafid A, Bouazza A, El Bouadili A, Zinck P, Visseaux M (2012) Highly stereoselec­tive coordination polymerization of β-myrcene from a lanthanide-based catalyst: Access to bio-sourced elastomers. J Polym Sci Pol Chem 50: 2898-2905
  34. Ventura A, Chenal T, Bria M, Bonnet F, Zinck P, Ngono-Ravache Y, Balanzat E, Visseaux M (2013) Trans-stereospecific polymerization of butadiene and random copolymerization with styrene using borohydrido neodymium/magne­sium dialkyl catalysts. Eur Polym J 49: 4130- 4140
  35. Valente A, Zinck P, Mortreux A, Visseaux M (2009) Catalytic chain transfer (co-) polymeriza­tion: Unprecedented polyisoprene CCG and a new concept to tune the composition of a statis­tical copolymer. Macromol Rapid Commun 30: 528-531
  36. Valente A, Stoclet G, Bonnet F, Mortreux A, Vis­seaux M, Zinck P (2014) Isoprene–styrene chain shuttling copolymerization mediated by a lan­thanide half-sandwich complex and a lanthani­docene: straightforward access to a new type of thermoplastic elastomers. Angew Chem Int Ed 53: 4638-4641
  37. Mahdavi H, Badiei A, Zohuri GH, Rezaee A, Jamjah R, Ahmadjo S (2007) Homogeneous polymerization of ethylene using an iron-based metal catalyst system. J Appl Polym Sci 103: 1517-1522
  38. Xiao A, Wang L, Liu Q, Yu H, Wang J, Huo J, Tan Q, Ding J, Ding W, Amin AM (2009) A nov­el linear− hyperbranched multiblock polyethyl­ene produced from ethylene monomer alone via chain walking and chain shuttling polymeriza­tion. Macromolecules 42: 1834-1837
  39. Mehdiabadi S, Soares JB (2016) Quantifying the copolymerization kinetics of ethylene and 1-oc­tene catalyzed with rac-Et (Ind)2ZrCl2 in a solu­tion reactor. Macromolecules 49: 2448-2457
  40. Gibson VC, Redshaw C, Solan GA (2007) Bis (imino) pyridines: surprisingly reactive ligands and a gateway to new families of catalysts. Chem Rev 107: 1745-1776
  41. Bianchini C, Giambastiani G, Rios IG, Man­tovani G, Meli A, Segarra AM (2006) Ethylene oligomerization, homopolymerization and copo­lymerization by iron and cobalt catalysts with 2, 6-(bis-organylimino) pyridyl ligands. Coordina­tion Chem Rev 250: 1391-1418
  42. Tong Z-Z, Zhou B, Huang J, Xu J-T, Fan Z-Q (2014) Regulation of crystallization kinetics, morphology, and mechanical properties of ole­finic blocky copolymers. Macromolecules 47: 333-346
  43.  Britovsek GJ, Gibson VC, McTavish SJ, Solan GA, White AJ, Williams DJ, Kimberley BS, Maddox PJ (1998) Novel olefin polymerization catalysts based on iron and cobalt. Chemical Communications 1998: 849-850
  44. Ahmadi M, Rezaei F, Mortazavi SMM, Entezam M, Stadler FJ (2017) Complex interplay of short-and long-chain branching on thermal and rheological properties of ethylene/α-olefin copo­lymers made by metallocene catalysts with oscil­lating ligand structure. Polymer 112: 43-52
  45. Awudza JA, Tait PJ (2008) The “comonomer ef­fect” in ethylene/α-olefin copolymerization us­ing homogeneous and silica-supported Cp2ZrCl2/ MAO catalyst systems: Some insights from the kinetics of polymerization, active center studies, and polymerization temperature. J Polym Sci Pol Chem 46: 267-277
  46. Ahmadi M, Nekoomanesh M, Jamjah R, Zohuri G Arabi H (2007) Modeling of slurry polym­erization of ethylene using a soluble Cp2ZrCl2/ MAO catalytic system. Macromol Theory Simul 16: 557-565
  47. Wang W (2015) Effect of diethylzinc on the ac­tivity of ethylene polymerization by metallocene catalyst. Macromol React Eng 9: 333-338
  48. Ahmadi M, Mortazavi SMM, Ahmadjo S, Zah­mati M, Valieghbal K, Jafarifar D, Rashedi R (2016) Evaluation of continuous and discrete melting endotherms in determination of struc­tural heterogeneities in Ziegler-Natta catalyzed linear low density polyethylene. Polyolefins J 3: 135-146
  49. Hosoda S (1988) Structural distribution of linear low-density polyethylenes. Polym J 20: 383-397
  50. Britovsek GJ, Clentsmith GK, Gibson VC, Goodgame DM, McTavish SJ, Pankhurst QA (2002) The nature of the active site in bis (imino) pyridine iron ethylene polymerisation catalysts. Catal Commun 3: 207-211
  51. Liu W, Wang W-J, Fan H, Yu L, Li B-G, Zhu S (2014) Structure analysis of ethylene/1-octene copolymers synthesized from living coordina­tion polymerization. Europ Polym J 54: 160-171
  52. Mortazavi M, Arabi H, Zohuri GH, Ahmadjo S, Nekoomanesh M, Ahmadi M (2009) Ethylene homo-and copolymerization using a bis-IndZr­Cl2 metallocene catalyst: Structural composition distribution of the copolymer. Macromol React Eng 3: 263-270
  53. Mortazavi SMM, Arabi H, Zohuri G, Ahmadjo S, Nekoomanesh M, Ahmadi M (2010) Copolymer­ization of ethylene/α-olefins using bis (2-phenyl­indenyl) zirconium dichloride metallocene cata­lyst: structural study of comonomer distribution. Polym Int 59: 1258-1265
  54. Kissin YV, Qian C, Xie G, Chen Y (2006) Multi-center nature of ethylene polymerization cata­lysts based on 2, 6-bis (imino) pyridyl complexes of iron and cobalt. J Polym Sci Polym Chem 44: 6159-6170