APPLICATION OF A NEW CHROMATOGRAPHIC METHOD, LC CAP, IN THE CHARACTERIZATION OF POLYSTYRENE-GRAFT-POLY(ETHYLENE-OXIDE) COPOLYMERS

The application of liquid chromatography at the critical adsorption po int (LC CAP) to a graft copolymer analysis is presented. This procedur e is based on the coupling of size exclusion and adsorption chromatogr aphic mechanisms. The data obtained by LC CAP (the apparent molecular weights of the polystyrene backbone, the number of the grafts per unit backbone and the amount of poly(ethylene oxide) in the graft copolyme rs) were compared with results of static light scattering (SLS), diffe rential refractometry and conventional SEC. SLS measurement were perfo rmed in toluene as an isorefractive solvent for polyethylene oxide sid e chains. Good agreement was found among the data obtained with all th e above methods and it can be concluded that the LC CAP method can als o be applied to graft copolymers with not very long side chains. (C) 1 998 Elsevier Science Ltd. All rights reserved.