SYMPOSIA PAPER Published: 01 January 1989

New Polymeric Materials for Temperature Controlled Release of Agricultural Chemicals


Currently there is significant interest in the development of controlled release delivery of agricultural agents: herbicides, insecticides, fungicides and fertilizers. Extended release of pesticides allow the potential for lowered doses, decreased application costs and reduced environmental risk. To date, however, existing systems are incapable of providing predictable delivery at a future date in response to an environmental need. Our approach is to develop an encapsulating polymer which will reversibly respond to ambient soil or air temperatures by releasing the core material at a temperature corresponding to the onset of the pest. We have now developed a class of polymeric membrane materials for the delayed delivery of pesticides. These materials exhibit large, reversible changes in permeability in response to seasonal temperature changes. Lab data is presented showing the permeability of films and microcapsules made from these polymers to a carbamate and organophosphate insecticide and a dinitroaniline herbicide over the temperature range of 10°C to 40°C. Reversible permeability changes from 200 to 2000% have been obtained over a 10°C interval.

Author Information

Greene, L
Stewart, RF
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Developed by Committee: E35
Pages: 74–84
DOI: 10.1520/STP22908S
ISBN-EB: 978-0-8031-5092-8
ISBN-13: 978-0-8031-1450-0