Remolding and Deconstruction of Industrial Thermosets via Carboxylic Acid-Catalyzed Bifunctional Silyl Ether Exchange.

Autor:	Husted KEL; Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States., Brown CM; Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States., Shieh P; Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States., Kevlishvili I; Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States., Kristufek SL; Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States., Zafar H; Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States., Accardo JV; Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States., Cooper JC; Department of Chemistry, University of Illinois at Urbana Champaign, Champaign County, Illinois 61820, United States., Klausen RS; Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21287, United States., Kulik HJ; Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States., Moore JS; Department of Chemistry, University of Illinois at Urbana Champaign, Champaign County, Illinois 61820, United States.; Department of Materials Science and Engineering, University of Illinois at Urbana Champaign, Champaign County, Illinois 60208, United States., Sottos NR; Department of Materials Science and Engineering, University of Illinois at Urbana Champaign, Champaign County, Illinois 60208, United States., Kalow JA; Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States., Johnson JA; Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States.
Jazyk:	angličtina
Zdroj:	Journal of the American Chemical Society [J Am Chem Soc] 2023 Jan 25; Vol. 145 (3), pp. 1916-1923. Date of Electronic Publication: 2023 Jan 13.
DOI:	10.1021/jacs.2c11858
Abstrakt:	Convenient strategies for the deconstruction and reprocessing of thermosets could improve the circularity of these materials, but most approaches developed to date do not involve established, high-performance engineering materials. Here, we show that bifunctional silyl ether, i.e., R'O-SiR 2 -OR'', (BSE)-based comonomers generate covalent adaptable network analogues of the industrial thermoset polydicyclopentadiene (pDCPD) through a novel BSE exchange process facilitated by the low-cost food-safe catalyst octanoic acid. Experimental studies and density functional theory calculations suggest an exchange mechanism involving silyl ester intermediates with formation rates that strongly depend on the Si-R 2 substituents. As a result, pDCPD thermosets manufactured with BSE comonomers display temperature- and time-dependent stress relaxation as a function of their substituents. Moreover, bulk remolding of pDCPD thermosets is enabled for the first time. Altogether, this work presents a new approach toward the installation of exchangeable bonds into commercial thermosets and establishes acid-catalyzed BSE exchange as a versatile addition to the toolbox of dynamic covalent chemistry.
Databáze:	MEDLINE
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