DETERMINATION OF PHOSPHORUS IN POLYMERS BY INAA

An INAA technique employing beta spectrometry was developed for the de termination of phosphorus in polymers. The (n, gamma) reaction on phos phorus produces P-32, half-life 14.3 days, a pure beta emitter with en d-po:nt energy 1.71 MeV. Polymer samples in the form of powders, films and pellets are irradiated and then counted with a plastic scintillat or. The beta spectrum is corrected for interferences (especially Sb, Z n and Br which are quantified by gamma spectrometry) and for energy lo ss in the thick sample. Samples must also be analyzed for S and Cl whi ch cause nuclear interferences. With an irradiation time of 4 hours at a neutron flux of 5.10(11) n.cm(-2).s(-1), decay time 10 days and cou nting time 10 minutes, the sensitivity is 520 counts/mu g phosphorus a nd the detection limit is typically 2 mu g/g.