Thermal degradation studies of polystyrene sulfonic and polyacrylic carboxylic cationites

The thermal degradation of polyacrylic carboxylic and polystyrene sulfonic cationites was investigated using thermal analysis (TG) combined with Scanning Electron Microscopy (SEM). Fourier Transform Infrared Spectroscopy (FTIR) was used to characterize the resins degradation steps. The carboxylic cationite undergoes degradation through dehydration forming polyanhydrides, decomposition of polyanhydrides through decarboxylation with elimination of CO₂ and CO. The sulfonic cationite undergoes degradation through dehydration, followed by decomposition of sulfonic acid functional groups liberating SO₂. It was observed that strong acid (−SO₃H⁺) cationite shows small mass loss of 55%, as against 88% mass loss shown by low-acidity carboxylic cationite. The possible reason for small mass loss of sulfonic cationite is discussed. The text was submitted by the authors in English.