Simultaneous thermal analysis of cationic, nonionic and anionic polyacrylamide

Annett Steudel; Frank Friedrich; Wolfgang Lieske; Wiebke Baille; Diethard König; Rainer Schuhmann; Katja Emmerich

doi:10.1016/j.heliyon.2019.e02973

Simultaneous thermal analysis of cationic, nonionic and anionic polyacrylamide

Heliyon. 2019 Dec 12;5(12):e02973. doi: 10.1016/j.heliyon.2019.e02973. eCollection 2019 Dec.

Authors

Annett Steudel¹, Frank Friedrich¹, Wolfgang Lieske¹, Wiebke Baille¹, Diethard König¹, Rainer Schuhmann², Katja Emmerich²

Affiliations

¹ Ruhr Universität Bochum (RUB), Chair of Soil Mechanics, Foundation Engineering and Environmental Geotechnics, Universitätsstraße 150, 44780, Bochum, Germany.
² Karlsruhe Institute of Technology (KIT), Competence Centre of Material Moisture (CMM), Hermann-von-Helmholtz-Platz 1, 76344, Eggenstein-Leopoldschafen, Germany.

Abstract

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 N₂, He or Ar gas flow. The object of this study was to investigate the thermal decomposition of cationic (PAM_S,τ40Cl), nonionic (PAM°_S), and anionic (NaPAM_S,τ40) 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 NH₃, CH₄ and NO together with H₂O, CO₂ and NO₂ during decomposition. The gas release differed between the three polymers. Stoichiometric calculations showed that PAM_S,τ40Cl and PAM°_S decomposed completely, while NaPAM_S,τ40 decomposed only partially and the Na present for charge balancing remained in the form of Na₂O. The thermal decomposition of PAM_S,τ40Cl, PAM°_S and NaPAM_S,τ40 under SynA occurred via pyrolysis and oxidation reactions.

Keywords: Agricultural soil science; Analytical chemistry; Evolved gas analysis; Materials science; Mineralogy; Organic chemistry; Polyacrylamide; Soil science; Thermal analysis.