Thermal Polymerization of Acrylamide by Differential Scanning Calorimetry

Thermal polymerization of acrylamide was studied by differential scanning calorimetry. Latent heat of fusion \bigtriangleup Hf and enthalpy of polymerization \bigtriangleup Hp values were found to be 36 and $-18.0 kcal mol^{-1}$, respectively. The overall activation energy E for the polymerization was calculated to be $19 k cal mol^{-1}$ up to 60% conversion. The added free-radical inhibitor (benzoquinone) was found to desensitize the thermal polymerization of acrylamide suggesting the polymerization to be a free-radical type. The existing rate equation for the heterogeneous bulk polymerization in the presence of initiators has been modified for the thermally initiated bulk polymerization of acrylamide. The experimental overall E value was found to agree well with the calculated E value when considering only the propagation and termination steps, thereby suggesting the process to be similar to postpolymerization of acrylamide