Preparation and characterization of branched chitosans
| Autor: | Kjell M. Vårum, Kristoffer Tømmeraas, Sabina P. Strand, Bjørn E. Christensen, Olav Smidsrød |
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| Rok vydání: | 2011 |
| Předmět: |
Polymers and Plastics
Dimer Organic Chemistry technology industry and agriculture macromolecular substances Random hexamer Condensation reaction Branching (polymer chemistry) Oligomer Chitosan chemistry.chemical_compound chemistry Polymerization Covalent bond Polymer chemistry Materials Chemistry Organic chemistry |
| Zdroj: | Carbohydrate Polymers. 83:1558-1564 |
| ISSN: | 0144-8617 |
| Popis: | Fully de-N-acetylated chito-oligomers were prepared by de-amination of chitosan using nitrous acid (HNO2). The dimer to hexamer fractions of chitosan oligomers were fractionated with preparative size-exclusion chromatography (SEC) and characterized using 1H NMR spectroscopy. The purified oligomers were polymerized by reductive N-alkylation by the action of NaCNBH3, in a reaction between the terminal 2,5-anhydro- d -mannofuranose (M-unit) and the primary amines of the repeating units (1 → 4) bound β- d -glucosamine (D-unit) resulting in a covalent bond and formation of secondary amines. The polymerized products were studied by SEC-RI and SEC-MALLS-RI and were confirmed to be branched reaching molecular weights of up to 10 000 g/mol. Analysis by 1H NMR spectroscopy confirmed that the chitosan oligomers had been branched by formation of secondary amines. Fully de-N-acetylated chitosan (FA |
| Databáze: | OpenAIRE |
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