Challenges in Synthesis and Analysis of Asymmetrically Grafted Cellulose Nanocrystals via Atom Transfer Radical Polymerization

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Volume Title
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
Date
2021-06-14
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Language
en
Pages
16
2702–2717
Series
Biomacromolecules, Volume 22, issue 6
Abstract
When cellulose nanocrystals (CNCs) are isolated from cellulose microfibrils, the parallel arrangement of the cellulose chains in the crystalline domains is retained so that all reducing end-groups (REGs) point to one crystallite end. This permits the selective chemical modification of one end of the CNCs. In this study, two reaction pathways are compared to selectively attach atom-transfer radical polymerization (ATRP) initiators to the REGs of CNCs, using reductive amination. This modification further enabled the site-specific grafting of the anionic polyelectrolyte poly(sodium 4-styrenesulfonate) (PSS) from the CNCs. Different analytical methods, including colorimetry and solution-state NMR analysis, were combined to confirm the REG-modification with ATRP-initiators and PSS. The achieved grafting yield was low due to either a limited conversion of the CNC REGs or side reactions on the polymerization initiator during the reductive amination. The end-tethered CNCs were easy to redisperse in water after freeze-drying, and the shear birefringence of colloidal suspensions is maintained after this process.
Description
Funding Information: This work was part of the Academy of Finland’s Flagship Program (Project Numbers 318890 and 318891, Competence Center for Materials Bioeconomy, FinnCERES). K.H. acknowledges postdoc funding provided by the Academy of Finland (Project Number 333905). A.K. and T.K. would like to acknowledge the Academy of Finland for funding under the project “WTF-Click-Nano” (Project #311255). G.D. and J.Z. acknowledge funding provided by the Swiss National Science Foundation (SNSF; Ambizione Grant No. PZ00P2_167900), and G.D., C.W., and J.Z. thank the Adolphe Merkle Foundation for support. J.Z. gratefully acknowledges the Serra Hunter Fellowship from the Generalitat de Catalunya. Publisher Copyright: ©
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Delepierre, G, Heise, K, Malinen, K, Koso, T, Pitkänen, L, Cranston, E D, Kilpeläinen, I, Kostiainen, M A, Kontturi, E, Weder, C, Zoppe, J O & King, A W T 2021, ' Challenges in Synthesis and Analysis of Asymmetrically Grafted Cellulose Nanocrystals via Atom Transfer Radical Polymerization ', Biomacromolecules, vol. 22, no. 6, pp. 2702–2717 . https://doi.org/10.1021/acs.biomac.1c00392