Beanlike structures

Polymers in Solution. Polyacrylamide is soluble in water at all concentrations, temperatures, and pH values. An extrapolated dieta temperature in water is approximately —40°C (17). Insoluble gel fractions are sometimes obtained owing to cross-link formation between chains or to die formation of imide groups along die polymer chains (18). In very dilute solution, polyacrylamide exists as unassociated coils which can have an ellipsoidal or beanlike structure (19). Large aggregates of polymer chains have been observed in hydrolyzed polyacrylamides (20) and in copolymers containing a small amount of hydrophobic groups (21). 

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