Chemical modification of inexpensive commercial polymers, such as polyacrylamide (PAM), is a safe methodology to obtain new copolymers. These new materials possess properties quite different from their precursors. In this case, we synthesized copolymers containing 1,3-oxazolic pendant groups. Molecular structures were confirmed by IR and C-13 NMR. Conversion yields were calculated by means of elemental analysis. Thermal properties were studied by TGA and DSC techniques. The dependence of viscosity with conversion degrees was also analyzed. Amide-5-phenyl-1,3-oxazole copolymer (APOC) of 2 h conversion time showed high viscosity values, for this reason its applicability as fracture fluid and temporary polymer plug was studied. Dynamic experiments with small sinusoidal deformations were also performed to investigate its rheological behavior. (C) 2007 Elsevier Ltd. All rights reserved.