TY - JOUR
T1 - Remolding and Deconstruction of Industrial Thermosets via Carboxylic Acid-Catalyzed Bifunctional Silyl Ether Exchange
AU - Husted, Keith E.L.
AU - Brown, Christopher M.
AU - Shieh, Peyton
AU - Kevlishvili, Ilia
AU - Kristufek, Samantha L.
AU - Zafar, Hadiqa
AU - Accardo, Joseph V.
AU - Cooper, Julian C.
AU - Klausen, Rebekka S.
AU - Kulik, Heather J.
AU - Moore, Jeffrey S.
AU - Sottos, Nancy R.
AU - Kalow, Julia A.
AU - Johnson, Jeremiah A.
N1 - This work was supported by the NSF Center for the Chemistry of Molecularly Optimized Networks (MONET), CHE-2116298. K.E.L.H. acknowledges support from the National Sciences and Engineering Research Council of Canada (for the NSERC PGSD fellowship). C.M.B. acknowledges NSERC for a Postdoctoral Fellowship. H.Z. acknowledges the National Science Foundation Graduate Research Fellowship Grant no. 2141064 for funding. This work used Expanse at San Diego Supercomputing Center through allocation CHE140073 from the Advanced Cyberinfrastructure Coordination Ecosystem: Services and Support (ACCESS) program, which is supported by National Science Foundation Grants #2138259, #2138286, #2138307, #2137603, and #2138296.
PY - 2023/1/25
Y1 - 2023/1/25
N2 - 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-SiR2-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-R2 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.
AB - 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-SiR2-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-R2 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.
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U2 - 10.1021/jacs.2c11858
DO - 10.1021/jacs.2c11858
M3 - Article
C2 - 36637230
AN - SCOPUS:85146345920
SN - 0002-7863
VL - 145
SP - 1916
EP - 1923
JO - Journal of the American Chemical Society
JF - Journal of the American Chemical Society
IS - 3
ER -