Modification of Kraft Lignin to Expose Diazobenzene Groups: Toward pH- and Light-Responsive Biobased Polymers
2015 (English)In: Biomacromolecules, ISSN 1525-7797, E-ISSN 1526-4602, Vol. 16, no 9, 2979-2989 p.Article in journal (Refereed) Published
A pH- and light-responsive polymer has been synthesized from softwood kraft lignin by a two-step strategy that aimed to incorporate diazobenzene groups. Initially, styrene oxide was reacted with the phenolic hydroxyl groups in lignin, to offer the attachment of benzene rings, thus creating unhindered reactive sites for further modifications. The use of advanced spectroscopic techniques H-1 and P-31 NMR, UV and FTIR) demonstrated that the reaction was quantitative and selective toward the phenolic hydroxyl groups. In a second step, the newly incorporated benzene rings were reacted with a diazonium cation to form the target diazobenzene motif, whose formation was again thoroughly verified. As anticipated, the diazobenzene-containing kraft lignin derivatives showed a pH-dependent color change in solution and light-responsive properties resulting from the cis-trans photoisomerization of the diazobenzene group.
Place, publisher, year, edition, pages
American Chemical Society (ACS), 2015. Vol. 16, no 9, 2979-2989 p.
Phenolic Hydroxyl-groups, Functional-groups, Biosynthesis, Chemicals, NMR
Polymer Chemistry Organic Chemistry
IdentifiersURN: urn:nbn:se:kth:diva-174927DOI: 10.1021/acs.biomac.5b00882ISI: 000361341700045PubMedID: 26288366ScopusID: 2-s2.0-84941702853OAI: oai:DiVA.org:kth-174927DiVA: diva2:861812
FunderKnut and Alice Wallenberg Foundation
QC 201510192015-10-192015-10-092015-12-07Bibliographically approved