Solution properties of dextran-polyacrylamide graft copolymers

Copolymers obtained by grafting polyacrylamide (PAA) onto polydextran (DEX) have been synthesised by ceric-ion-reduced redox initiation method. These copolymers have been characterized by light scattering, self-exclusion chromatography and viscometry in aqueous solutions. The short range molecular structure has been studied by small-angle X-ray scattering. From these results it is suggested that close to the anchoring point the grafted chains are extended while they take on a random conformation far from this point. A few investigations have been carried out in water/DMF (dimethyl formamide) mixtures. It is observed that the molecular weight depends strongly on the dimethyl formamide fraction. These results are discussed by contemplating the existence of PAA/DMF complexes.