From Epoxide to Cyclodithiocarbonate Telechelic Polycyclooctene through Chain-Transfer Ring-Opening Metathesis Polymerization (ROMP): Precursors to Non-Isocyanate Polyurethanes (NIPUs)
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- 作者：Elise Vanbiervliet ; Stéphane Fouquay ; Guillaume Michaud ; Frédéric Simon ; Jean-François Carpentier ; Sophie M. Guillaume
- 刊名：Macromolecules
- 出版年：2017
- 出版时间：January 10, 2017
- 年：2017
- 卷：50
- 期：1
- 页码：69-82
- 全文大小：749K
- ISSN：1520-5835
文摘
Telechelic polycyclooctenes (PCOEs) have been successfully synthesized by ring-opening metathesis polymerization (ROMP)/cross-metathesis (CM) of cyclooctene (COE) using Grubbs’ second-generation catalyst (G2) in the presence of epoxide-functionalized chain-transfer agents (CTAs). The monofunctional epoxide oxiran-2-ylmethyl acrylate CTA (1) afforded the isomerized α-(glycidyl alkenoate),ω-propenyl functional (IMF) PCOEs. The use of 1,4-benzoquinone (BZQ) as additive completely inhibited the C═C isomerization process, thereby leading selectively to α-(glycidyl alkenoate),ω-vinyl telechelic (MF) PCOE. On the other hand, difunctional epoxide CTAs, bis(oxiran-2-ylmethyl) fumarate (3), bis(oxiran-2-ylmethyl) maleate (4), bis(oxiran-2-ylmethyl) (E)-hex-3-enedioate (5), and (Z)-1,4-bis(oxiran-2-ylmethoxy)but-2-ene (6), selectively afforded the corresponding α,ω-di(glycidyl alkenoate) telechelic PCOEs (DF) along with minor amounts of cyclic nonfunctional (CNF) PCOE. In the presence of these difunctional symmetric CTAs, the mechanism is proposed to proceed through a tandem one-pot CM/ROMP/ring-closing metathesis (RCM) approach. CM was more effective with Z- than E-configurated CTAs (4 > 6 ≫ 3 ≫ 5), regardless of the presence of a methylene group in-between the C═C double bond and the glycidyl moiety. Subsequent dithiocarbonatation of the α,ω-diepoxide telechelic PCOEs upon reaction with CS2 in the presence of LiBr quantitatively afforded the first examples of bis(cyclodithiocarbonate) end-functional PCOEs. Ensuing aminolysis of the bis(cyclodithiocarbonate) telechelic PCOEs with the polyether (triethylene glycol) diamine JEFFAMINE EDR-148 quantitatively afforded, at room temperature without any added catalyst, the desired poly(mercaptothiourethane)s NIPUs, as evidenced from FTIR spectroscopy, TGA, and DSC analyses.