scleroglucan and chloroacetic-acid

The synthesis of negatively and positively charged polyelectrolytes from scleroglucan is described. Polycarboxylates were synthesised through nucleophilic substitution with chloroacetic acid or through a selective 2,2,6,6-tetramethyl-l-piperidinyloxy (TEMPO)-mediated oxidation of the primary alcohol groups. Amine groups were introduced through nucleophilic substitution with 2-chloroethylamine or 3-chloropropylamine. Reaction conditions were varied to obtain insight into the influence of variables on the degree of substitution. The conformational behaviour of the obtained polyelectrolytes was studied as a function of pH, temperature and solvent. For the products with a low degree of modification, evidence of an ordered conformation was found, whereas the polymers with a higher degree of modification behaved as random coils in solution. The negatively charged polymers were reticulated using the Ugi four-component condensation, obtaining negatively charged hydrogels. The positively charged polymers were reticulated using diethyl squarate (3,4-diethoxy-3-cyclobutene-1,2-dion, DES) to obtain positively charged hydrogels.

Topics: Absorption; Acetates; Carbohydrate Conformation; Carbohydrate Sequence; Cross-Linking Reagents; Cyclic N-Oxides; Electrolytes; Glucans; Hydrogels; Hydrogen-Ion Concentration; Methylation; Molecular Sequence Data; Oxidation-Reduction; Solvents; Static Electricity; Temperature