The porous structure and pore sizes of the gels can be tuned by changing the curing conditions, such as temperature, initiator amount, or stoichiometric ratio of isocyanate and ethyl carbazate. Generally, a porous structure is a desired property of hydrogels, as it increases the surface area and aids diffusion of molecules, such as drugs and biologics. We analyzed the thermal stability of the hydrogel using thermogravimetric analysis (TGA). The TGA analysis showed that the semicarbazide gel was thermally the least stable (Fig. ). It should be noted that in the urazole cyclization step, the high temperature probably helped unreacted isocyanate (i.e., isocyanate remaining in the gel network) to react to form extra bonds, resulting in higher thermal stability for urazole gels. The urazole free acid gel was slightly more stable than its potassium salt version below 300°C. This might be due to the hydrogen bonding capability of the urazole group when urazole is in free acid form. Under the same conditions, the urazole-potassium salt has a residual mass of 14.85% of its weight after heating to 700°C, whereas semicarbazide 5.01% and free acid has only 0.05%. The potassium mass contribution to the material is heoretically 12.90% that explains high residual mass for urazole potassium gel.