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

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• 作者：Finizia Auriemma ; Oreste Tarallo ; Claudio De Rosa ; Anna Malafronte ; Rocco Di Girolamo ; Antonio Proto ; Carmine Capacchione ; Rosa Ricciardi ; Daniela Saviello
• 刊名：Macromolecules
• 出版年：2015
• 出版时间：October 13, 2015
• 年：2015
• 卷：48
• 期：19
• 页码：6931-6940
• 全文大小：530K
• ISSN：1520-5835

文摘

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鈥?3 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鈥?00 掳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 脜 and are arranged in a monoclinic unit cell with parameters a = 5.70 脜, b (unique axis) = 14.95 脜, c (chain axis) = 5.13 脜, and 尾 = 114.4掳, according to the space group symmetry Pn.