The thermal degradation of FIBAN K-l fibrous copper-containing and copper-f
ree cationites was studied by differential thermal analysis, IR and ESR spe
ctroscopy, X-ray diffraction, and atomic absorptive analysis. It was shown
that Cu2+ ions strongly influence the processes that proceed during the sam
ple heating in the range from 315 to 340 degreesC. It was demonstrated that
the state of copper and the concentration of its paramagnetic ions vary wi
th temperature.