| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 1383609 | Carbohydrate Polymers | 2015 | 8 Pages |
•Amphoteric derivatives were obtained by cationization of kappa and iota carrageenan.•Reaction was carried out with 3-chloro-2-hydroxypropyltrimethylammonium chloride.•Products were characterized by elemental analysis, FT-IR, NMR, and ESI MS.•Mechanical and rheological behavior showed interesting properties.•Modified carrageenans improved flocculation of kaolin compared to controls.
Commercial kappa- and iota carrageenans were cationized with 3-chloro-2-hydroxypropyltrimethylammonium chloride in aqueous sodium hydroxide solution. For kappa-carrageenan three derivatives with different degrees of substitution were obtained. Native and amphoteric kappa-carrageenans were characterized by NMR and infrared spectroscopy, scanning electron and atomic force microscopy; methanolysis products were studied by electrospray ionization mass spectrometry. Young moduli and the strain at break of films, differential scanning calorimetry, rheological and flocculation behavior were also evaluated; the native and the amphoteric derivatives showed different and interesting properties. Cationization of iota-carrageenan was more difficult, indicating as it was previously observed for agarose, that substitution starts preferentially on the 2-position of 3,6-anhydrogalactose residues; in iota-carrageenan this latter unit is sulfated.
