Synthesis, characterization and evaluation of reactional parameters on substitution degree of N-hexyl-N-methylene phosphonic chitosan

Abstract

N-methylene phosphonic chitosan (NMPC) is treated with hexyl aldehyde to give an imine, which is easily converted into N-hexyl-N-methylene phosphonic chitosan (HNMPC) under mild conditions. The structure of this new chitosan derivative is characterized by FT- IR, 1H, 13C, 31P, 1H13C–HSQC NMR, SEM and XRD. The influence of reactional parameters on the substitution degree (DS), evidenced that a mol ratio 1.50:1.00 (hexyl aldehyde: free amino groups); a reaction time of 1 h. and 45 °C of temperature afford the best DS. HNMPC molecular weight is 12,768.62 Da. It shows good emulsifying properties giving o/w emulsions with high stability in time. Microscopic observation as well as particle size distribution show an unimodal droplet size distribution with low droplet diameters. Preliminary tests lead us to believe that this new polymer has good film forming properties.