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Chemija / Chemistry

ISSN 0235-7216
ISSN 2424-4538 (online)

2009 m. Nr. 2

Polyampholytes from natural building blocks: synthesis and properties of chitosan-O-alginate copolymers
Ugnė JANČIAUSKAITĖ, Česlav VIŠNEVSKIJ, Kostas RADZEVIČIUS, Ričardas MAKUŠKA

Chitosan-O-alginate comb copolymers with a different degree of chitosan substitution were synthesized using chitosan protected by phthaloylation and “activated” by tosylation, and reduced low-molecular-weight sodium alginate. The obtained chitosan derivatives were characterized by FT-IR and 1H NMR spectroscopy, functional group analysis, viscometry and potentiometric titration. The novel nature-friendly polyampholytes contained a 15–25-fold excess of carboxyl groups and were soluble in neutral and alkaline water. The intrinsic viscosity and molecular weight of these chitosan derivatives were relatively low, suggesting a significant breakdown of chitosan backbone under derivatization. The solution viscosity of the polyampholytes had a tendency to decrease by lowering the pH toward a supposed isoelectric point at pH 3.5–4.0. Comb-shaped copolymers in aqueous solutions are expected to form tight coils which are stabilized by intra- and intermolecular complexes between carboxyl and amine groups.

Keywords: chitosan, sodium alginate, comb copolymer, polyampholyte, nature-friendly

Issues:

2017 - Vol.28
No. 1, No. 2, No. 3

2016 - Vol.27
No. 1, No. 2, No. 3, No. 4

2015 - Vol.26
No. 1, No. 2, No. 3, No. 4

2014 - Vol.25
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2013 - Vol.24
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2012 - Vol.23
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2011 - Vol.22
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2001 - Vol.12
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