Structure of Isotactic Ethylene/4-Methyl-1,3-pentadiene Alternating Copolymers Obtained from Postmetallocene Catalysts

TitleStructure of Isotactic Ethylene/4-Methyl-1,3-pentadiene Alternating Copolymers Obtained from Postmetallocene Catalysts
Publication TypeArticolo su Rivista peer-reviewed
Year of Publication2015
AuthorsAuriemma, F., Tarallo O., De Rosa C., Malafronte A., Di Girolamo R., Proto A., Capacchione C., Ricciardi Rosa, and Saviello D.
JournalMacromolecules
Volume48
Pagination6931-6940
ISSN00249297
KeywordsAlternating copolymer, Catalyst precursors, Catalysts, Crystalline materials, Equimolar concentrations, Ethylene, Isotactic copolymers, Nuclear magnetic resonance spectroscopy, Post-metallocene catalysts, Space-group symmetry, Structure and thermal properties, Synthesis (chemical), Trans-planar conformation
Abstract

The structure and thermal properties of a new class of isotactic copolymers of ethylene (E)/4-methyl-1,3-pentadiene (4MPD) with 4MPD content in the range 40-73 mol % and of isotactic poly-1,2-(4-methyl-1,3-pentadiene) (iP4MPD) homopolymer have been analyzed. The copolymers have been synthesized using 1,4-dithiabutanediyl-linked bis(phenolate) titanium complexes as catalyst precursors, activated by methylaluminoxane. Solution 13C NMR analysis reveals the tendency of the catalyst system to produce copolymers with alternating 4MPD/E constitution. All copolymers are crystalline and show melting temperatures in the range 90-100 °C. The samples with nearly equimolar concentration of units crystallize in a new crystalline form because of the alternating constitution. Structural analysis indicates that in this new form the alternating 4MPD-E sequences assume a nearly trans-planar conformation with periodicity c = 5.13 Å and are arranged in a monoclinic unit cell with parameters a = 5.70 Å, b (unique axis) = 14.95 Å, c (chain axis) = 5.13 Å, and β = 114.4°, according to the space group symmetry Pn. © 2015 American Chemical Society.

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URLhttps://www.scopus.com/inward/record.uri?eid=2-s2.0-84944097431&doi=10.1021%2facs.macromol.5b01660&partnerID=40&md5=ff7cbae3292615c6d99fbb3b5da95532
DOI10.1021/acs.macromol.5b01660