Aalto University Schools of Technology - electronic academic dissertations - http://otalib.aalto.fi/fi/kokoelmat_tiedonhaku/e-julkaisut/vaitoskirjat/
Aalto

α,ω-Diene Functionalized Polyethene Prepared with Metallocene Catalyst

Pirjo Pietikäinen

Dissertation for the degree of Doctor of Science in Technology to be presented with due permission of the Department of Chemical Technology for public examination and debate in Auditorium E at Helsinki University of Technology (Espoo, Finland) on the 12th of October, 2007, at 12 noon.

Overview in PDF format (ISBN 978-951-22-8956-1)   [2383 KB]
Dissertation is also available in print (ISBN 978-951-22-8955-4)

Abstract

Ethene was copolymerized with linear nonconjugated dienes (1,5-hexadiene (HD), 1,7-octadiene (OD), 7-methyl-1,6-octadiene (MOD)) using homogeneous metallocene catalysts (cyclopentadienylzirconium dichloride, Cp2ZrCl2; rac-ethylenebis(indenyl)zirconium dichloride, Et[Ind]2ZrCl2; bis(n-butylcyclopentadienyl)zirconium dichloride, (n-BuCp)2ZrCl2; rac-ethylenebis(indenyl)hafnium dichloride, Et[Ind]2HfCl2). The cocatalyst was methylaluminoxane (MAO).

A wide variety of structures can be formed in the copolymerization of ethene and linear non-conjugated dienes. Whether the diene is incorporated in polyethene chain as branches or cyclic structures is determined by the choice of diene, metallocene catalyst, and polymerization conditions. HD is easily cyclized, forming 1,3-cyclopentane rings in the polyethene chain, MOD has a methyl group that prevents its cyclization, and the ability of OD to cyclize depends on the catalyst. In addition, it is important to be able to control the crosslinking, which is effectively diminished by increasing the polymerization temperature.

Polyethenes with modified rheologies can be produced by incorporating long-chain branching (LCB). LCB is desired in metallocene-catalyzed polyethene to enhance processability. The ability of metallocenes to induce LCB in situ in ethene polymerization was exploited. Since the formation of LCB is favored by the presence of vinyl groups, copolymerizations with diene offer a useful approach to the formation of LCB. Reasonable amounts of LCB were formed in copolymers of ethene with both HD and OD.

Ethene/diene copolymers were post-polymerization functionalized to reactive silane functional polyethenes (PE-co-SiX, X=Cl, OEt, Ph). These functional polyethenes were able to interact with filler and transfer part of the filler to the rubbery phase of heterophasic polypropene. Significant improvement was thereby achieved in the toughness as compared with unfilled hPP, both below the Tg of PP and at ambient temperature.

This thesis consists of an overview and of the following 6 publications:

  1. Pietikäinen, P., Väänänen, T., and Seppälä, J.V., Copolymerization of Ethylene and Non-conjugated Dienes with Cp2ZrCl2/MAO Catalyst System, European Polymer Journal 35 (1999) 1047-1055. © 1999 Elsevier Science. By permission.
  2. Pietikäinen, P., Seppälä, J.V., Ahjopalo, L., and Pietilä, L.-O., Copolymerization of Ethylene and Non-conjugated Dienes with Cp2ZrCl2/MAO Catalyst System: Effect of Polymerization Temperature on the Copolymer Structure, European Polymer Journal 36 (2000) 183-192. © 2000 Elsevier Science. By permission.
  3. Pietikäinen, P., Starck, P., and Seppälä, J.V., Characterization of Comonomer Distributions in Ethylene/Diene Copolymers by 13C-NMR, and Using the Segregation Fractionation Technique by DSC and DMTA, Journal of Polymer Science Part A: Polymer Chemistry 37 (1999) 2379-2389.
  4. Pietikäinen, P., Malmberg, A., Löfgren, B., and Seppälä, J., Studies on Properties of Metallocene Catalysed Copolymers of Ethylene and Linear, Non-conjugated Dienes, in Kaminsky, W. (ed.), Metalorganic Catalysts for Synthesis and Polymerization: Recent Results by Ziegler-Natta and Metallocene Investigations, Springer-Verlag, Berlin, Germany, 1999, pp. 502-508.
  5. Kokko, E., Pietikäinen, P., Koivunen, J., and Seppälä, J.V., Long-Chain-Branched Polyethene by the Copolymerization of Ethene and Nonconjugated α,ω-Dienes, Journal of Polymer Science Part A: Polymer Chemistry 39 (2001) 3805-3817.
  6. Lipponen, S., Pietikäinen, P., Vainio, U., Serimaa, R., and Seppälä, J., Silane Functionalized Ethylene/Diene Copolymer Modifiers in Composites of Heterophasic Polypropylene and Microsilica, Polymers and Polymer Composites 15 (2007) 343-355. © 2007 Smithers Rapra Technology. By permission.

Keywords: polyethene, linear nonconjugated diene, metallocene, functionalization

This publication is copyrighted. You may download, display and print it for Your own personal use. Commercial use is prohibited.

© 2008 Helsinki University of Technology

Last update 2011-05-26