Revealed pathways of furan ring opening and surface crosslinking in biobased polyfurfuryl alcohol

Aldehydes are conjugated while ketones are non-conjugated. Oxidative ring opening explain the stiffer surface of PFA materials. [Display omitted] •Ring opening in Polyfurfuryl alcohol occurs preferentially on furan-end groups.•2D-NMR investigations allow to highlight the presence of aldehyde functio...

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Bibliographic Details
Published in:European polymer journal Vol. 187; p. 111869
Main Authors: Delliere, Pierre, Guigo, Nathanael
Format: Journal Article
Language:English
Published: Elsevier Ltd 03.04.2023
Elsevier
Subjects:
2D-NMR
Biobased thermoset
Chemical Sciences
Oxidation
Poly(furfuryl alcohol)
Ring-opening
Surface crosslinking
Surface crosslinking
Oxidation
Poly(furfuryl alcohol)
2D-NMR
Biobased thermoset
Ring-opening
ISSN:0014-3057, 1873-1945
Online Access:Get full text
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Summary:Aldehydes are conjugated while ketones are non-conjugated. Oxidative ring opening explain the stiffer surface of PFA materials. [Display omitted] •Ring opening in Polyfurfuryl alcohol occurs preferentially on furan-end groups.•2D-NMR investigations allow to highlight the presence of aldehyde functions in PFA.•Oxidative and hydrolytic ring opening pathways are proposed.•The formed conjugated aldehydes are good dienophile prone for Diels-Alder ccycloaddition. Poly(furfuryl alcohol) – (PFA) is a biobased thermoset known for its highly crosslinked structure. Bidimensional NMR (2D-NMR) was employed to give new insights on the complex structural organization in PFA with a special emphasis on the side structures resulting from furan ring-opening. Interestingly, the presence of aldehyde functions was for the first time clearly highlighted and quantified in PFA resins. Overall, the aldehydes account for about 20 % of the total carbonyls present in PFA. Results from HSQC and HMBC sequences allowed proposing two pathways for the furan ring opening reactions. The first one is an hydrolytic-ring opening leading to levulinic like species. The second one is rather an oxidative furan-ring opening leading to conjugated aldehydes. These conjugated aldehydes are prone to crosslink via Diel-Alder cycloadditions with furanic entities thus leading to crosslinking. At macroscopic scale, this newly proposed crosslinking pathway would explain the formation of the rigid shell formed at the external surfaces of PFA resins.
ISSN:0014-3057
1873-1945
DOI:10.1016/j.eurpolymj.2023.111869