New hydrogels based on (MAA) and (NVP) copolymers crosslinked with (BAA), were prepared by free radical cross-linking copolymerization, with a NVP percent molar composition of 10, 47.5 and 85. These hydrogels have been characterized by (FTIR), (SEM), (TGA /DSC) coupling. The results show four steps of degradation. The degradation rate is inversely proportional to the mole percent of NVP, and SEM shows that the hydrogels have a pore size between 7.14 to 13.33 μm.