Preparation of controlled-release starch encapsulated pesticides: Advantages and opportunities of extrusion processing

Recent advances have been made in technology for encapsulation of pesticides within a starch matrix. This technology involves the entrapment of pesticides in the matrix without need for either crosslinking chemicals, ancillary polymers, or modification of the starch substrate. The latest technology utilizes extrusion compounding techniques to achieve the entrapment. Several types of solid, crystalline, and liquid pesticides have been successfully entrapped in unmodified cornstarch matrices by continuous, twinscrew extrusion processes developed at this Center. This report reviews and summarizes various aspects of the encapsulation research and development carried out over the past 3 years. Variables affecting the encapsulation efficiency and release rate properties of the products are discussed. The preparation, evaluation, and efficacy of starch encapsulated pesticides (herbicides) produced by a simulated scaled-up extrusion process and an engineering feasibility study for their large scale production will be reported by others. (author). 17 refs, 9 figs, 5 tabs