Specific modifications of galactomannans

A sample of galactomannan extracted from the seeds of Leucaema leucocephala is modified on a specific position using the reactant 2,2,6,6-tetramethylp iperidine-1-oxyl (TEMPO). This method allows oxidation at the C-6 position of galactose and free mannose (not connected to a side group). The kinetics of oxidation is followed under well-defined conditions. Different methods are proposed for the characterization of the modified polysaccharides and N MR spectroscopy is shown to give useful information. New polyelectrolytes a re produced with different degrees of oxidation. Successive alkylations on the C-6 sites are investigated. The degree of alkylation obtained remains l ow but it can be increased easily to reinforce the amphiphilic character. ( C) 2000 Elsevier Science Ltd. All rights reserved.