Browsing by Author "Zaid, Michael"

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    Determination of the Release Mechanism of Polymer Supported Pesticides
    (Addis Ababa Universty, 1988-06) Zaid, Michael; Socher, M (PhD)
    The release mechanisms, of the two organophosphorus insecticides, malathion and chlorpyrifos, were studied from the polymer films prepared in the Laboratory. Furthermore, the behaviour of the release of chlorpyrifos from the granular commercial sample was also studied. Thus, the diffusion of the insecticides from the insecticidal polymer films; cellulose acetate impregnated with chlorpyrifos, and cellulose acetate impregnated with malathion, have shown the characterstic features of a Fickian diffusion, at higher temperature ( 100° C ), and the apparent diffusion coefficients have been calculated. While, at temperatures lower than 100°c, the release has shown a non-Fickian diffusion. On the other hand, the release of chlorpyrifos from the polyethylene vinyl acetate coplymer and the Suscon polymer films have shown a non- Fickian diffusion at all the temperatures of study (70°c, 60°C, and 50°C). Moreover, the release behaviour of the Suscon commercial sample was studied at different conditions; in soil, water, and open air. And the release was found to be dependent on the concentration of the insecticide, raihfall and temperature