Study of sodium dodecyl sulfate/poly(propylene oxide) methacrylate mixed micelles for the synthesis of thermo-associative polymers by micellar polymerization
Résumé
Water soluble associative polymers based on polyacrylamide (PAM) grafted with short poly(propylene oxide) (PPO) chains as pendant groups were synthesized. Two different methods were used (1) homogeneous (water + acetonitrile) (2) micellar copolymerization, in the presence of sodium dodecyl sulphate (SDS) to solubilize the hydrophobic comonomer, PPO methacrylate (PPOMA). As expected from the literature, random or blocky distribution of PPO along the PAM chain, respectively, is obtained by these two methods. This work focuses on the characterization of the micellar reactional medium in order to have a good estimate of the length of the PPO sequences along the main chain. An extensive study of the mixture SDS/PPOMA was performed, by using fluorimetry, light scattering and conductimetry, to characterize the initial mixed micelles (critical micellar concentration and aggregation number). It is shown that the total aggregation number of the micelles and that of SDS decrease when the concentration of PPOMA increases. In addition, preliminary turbidimetry and viscosimetry studies of the thermo-associative properties of the two polymers are given. © 2002 Society of Chemical Industry.