Simultaneous thermal analysis of cationic, nonionic and anionic polyacrylamide.

Polyacrylamide (PAM) and its derivatives are the most commercially available water-soluble polymers and are frequently used for the production of clay-polymer composites. The characterization of their thermal behavior and decomposition was carried out mainly under reduced conditions by using N, He or Ar gas flow. The object of this study was to investigate the thermal decomposition of cationic (PAMCl), nonionic (PAM°), and anionic (NaPAM) polyacrylamide under synthetic air (SynA) in detail using a thermogravimetry/differential scanning calorimetry (TG/DSC) system connected to a quadrupole mass spectrometer (MS). MS data indicated the release of NH, CH and NO together with HO, CO and NO during decomposition. The gas release differed between the three polymers. Stoichiometric calculations showed that PAMCl and PAM° decomposed completely, while NaPAM decomposed only partially and the Na present for charge balancing remained in the form of NaO. The thermal decomposition of PAMCl, PAM° and NaPAM under SynA occurred via pyrolysis and oxidation reactions.