Di- and Triblock Copolymers Based on Polyethylene and Polyisobutene Blocks. Toward New Thermoplastic Elastomers

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• 作者：Edgar Espinosa ; Bernadette Charleux ; Franck D鈥橝gosto ; Christophe Boisson ; Ranjan Tripathy ; Rudolf Faust ; Corinne Souli茅-Ziakovic
• 刊名：Macromolecules
• 出版年：2013
• 出版时间：May 14, 2013
• 年：2013
• 卷：46
• 期：9
• 页码：3417-3424
• 全文大小：432K
• 年卷期：v.46,no.9(May 14, 2013)
• ISSN：1520-5835

文摘

Azido end-functionalized polyethylenes (PE-N₃, 2250 or 2500 g mol^鈥?, 膼 = 1.2, functionality higher than 88%) were reacted with alkyne end-functionalized or telechelic polyisobutenes (PIB-C鈮H: M_n = 2400 g mol^鈥?, 膼 = 1.1; HC鈮-PIB-C鈮H: M_n = 6900 g mol^鈥?, 膼 = 1.2, respectively) using the 1,3-dipolar cycloadddition reaction in a mixture of toluene and dimethylformamide at 110 掳C. The reaction led to the quantitative formation of di- and triblock copolymers (PE-b-PIB and PE-b-PIB-b-PE) that were characterized by size exclusion chromatography and ¹H NMR analyses. The original copolymer PE-b-PIB-b-PE that incorporates hard semicrystalline PE blocks and a soft PIB block was further studied by differential scanning calorimetry, optical microscopy, X-ray scattering, and dynamic mechanical analysis. It was shown that the crystallinity of PE segments was not perturbed by the PIB phase and that the T_g of PIB was slightly raised because of chain motion restrictions due to PE crystallites. In addition, mechanical analyses showed that PE-b-PIB-b-PE behaved as a thermoplastic elastomer over a broad temperature range (0鈥?10 掳C) with a tensile strength of 4 MPa and an elongation at break of 16%. The use of blocks of higher molar mass should improve the copolymer nanostructuration.