Abstract: Anew way for preparing crosslinked starch matrix for slow release of carboxylic-containing herbicides had been investigated and proposed. The matrix was crosslinked by formaldehyde in encapsulation process in order to reduce the swellability and release rates, and to raise the performance of slow release and resistance to water. By using 2,4,5-T and 2,4-D as model herbicides, the improvement on swellability, encapsulation efficiency and release characteristic of the crosslinked matrix as compared with native starch had been evaluated. The effects of formaldehyde amount, herbicide contents, and particle sizes on the matrix behavior and release rates were also investigated.

Key words: Starch, Encapsulation, Slow release, Crosslinking