Thermal analysis of controlled‐release formulations based on entrapment of a larvicide in cross‐linked carboxymethylcellulose

摘要

AbstractThermal analysis of controlled‐release formulations of fenthion, prepared by its entrapment in cross‐linked carboxymethylcellulose and carboxymethylcellulose–gelatin matrices was carried out by thermogravimetric analysis and under accelerated storage conditions. Thermograms of samples of sodium carboxymethylcellulose, cross‐linked polymer samples, and the formulations were studied. The thermogravimetric analysis showed improved heat resistance and retention of fenthion or its decomposition products in the formulated samples. The decomposition maximum of technical‐grade fenthion was 260°C and the corresponding weight loss was about 90, whereas fenthion or its decomposition products appear to be retained up to temperatures ranging from 400 to 500°C in the formulations. The half‐life of fenthion in the mechanical mixture with the carrier polymer was found to range from 19.92 to 29.98 days, whereas in the formulated samples, it was found to range between 41.54 and 113.35 days. © 1994 John W