Abstract
A family of stereoregular poly(amide-triazole)s derived from D-galactose was obtained following several principles of Green Chemistry, namely bio-based starting materials, high yields, benign reaction conditions, energy efficiency, catalysis, atom economy, and chemical degradation. The monomer precursors, the α-azido-ω-N-alkynylamide derivatives, were prepared from D-galactose, which was oxidized to D-galactono-1,4-lactone and the secondary hydroxyl groups were protected as isopropylidene acetals. The AB-type azide-alkyne click polymerization led to poly(amide-triazole)s. The Cu(I)-catalyzed polymerization led regioselectively to 1,4-disubstituted triazole ring, and hence to a stereoregular polymer. In contrast, the thermal polymerization produced also 1,5-disubstituted triazole units. The stereoregular polymer underwent acid-promoted chemical degradation, and the degradation products were identified. Moreover, selective removal of theacid labile acetonide moieties led to a partially protected poly(amide-triazole). This polymer was further modified using the “grafting from” approach. Thus, the ROP of caprolactone initiated from the free hydroxyl groups of the polymer led to a linear poly(amide-triazole) grafted with short biodegradable polycaprolactone side-chains. On the other hand, complete HO-deprotection of the monomer gave, after click polymerization, the fully unprotected polymer. The protected poly(amide-triazole)s showed a higher thermal stability compared to the hydroxylated derivatives, which could undergo dehydration processes at lower temperatures. Similarly, the partially protected polymer gave a lower Tg value, in agreement with an increasing degree of structural disorder (non-stereoregular materials) and/or lower molecular weight.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.