Synthesis of polypropylene-co-p-methylstyrene copolymers by metallocene and Ziegler-Natta catalysts

H. L. Lu, S. Hong, Tze-chiang Chung

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54 Scopus citations

Abstract

This paper discusses the copolymerization reaction of propylene and p-methylstyrene (p-MS) via four of the best-known isospecific catalysts, including two homogeneous metallocene catalysts, namely, {SiMe2[2-Me-4-Ph(Ind)]2}ZrCl2 and Et(Ind)2ZrCl2, and two heterogeneous Ziegler-Natta catalysts, namely, MgCl2/TiCl4/ electron donor (ED)/AlEt3 and TiCl3. AA/Et2AlCl. By comparing the experimental results, metallocene catalysts show no advantage over Ziegler-Natta catalysts. The combination of steric jamming during the consective insertion of 2,1-inserted p-MS and 1,2-inserted propylene (k21 reaction) and the lack of p-MS homopolymerization (k22 reaction) in the metallocene coordination mechanism drastically reduces catalyst activity and polymer molecular weight. On the other hand, the Ziegler-Natta heterogeneous catalyst proceeding with 1,2-specific insertion manner for both monomers shows no retardation because of the p-MS comonomer. Specifically, the supported MgCl2/TiCl4/ED/AlEt3 catalyst, which contains an internal ED, produces copolymers with high molecular weight, high melting point, and no p-MS homopolymer.

Original languageEnglish (US)
Pages (from-to)2795-2802
Number of pages8
JournalJournal of Polymer Science, Part A: Polymer Chemistry
Volume37
Issue number15
DOIs
StatePublished - Aug 1 1999

All Science Journal Classification (ASJC) codes

  • Polymers and Plastics
  • Organic Chemistry
  • Materials Chemistry

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