Acetochlor is an important herbicide for gramineous weeds and some small seed broadleaf<br />weeds. Controlled-release formulations of herbicide are highly desirable not only for attaining<br />the most effective utilisation of the weed control, but also for reducing environmental<br />pollution. Acetochlor was incorporated in poly (butyl methacrylate-diacetone acrylamide)<br />based formulation to obtain controlled release properties. The acetochlor nanocapsules were<br />characterised by size distribution, infrared spectroscopy (IR) and field emission scanning<br />electron microscopy (FESEM), and factors related to loading efficiency, swelling behaviour<br />of the formulation were investigated. For this controlled-release formulation, the loading<br />efficiency could reach about 50% (w/w). n, the diffusion parameter was indicative of the<br />transport mechanism, and the values for ‘n’ were in the range of 0.28–0.61, which indicated<br />that the release of acetochlor was diffusion-controlled. The time taken for 50% of the active<br />ingredient to be released into water, t50, was also calculated for the comparison of formulations<br />in different conditions. The formulation with higher temperature and more diacetone<br />acrylamide had lower value of t50, which means a quicker release of the active ingredient.<br />This study highlighted some pieces of evidence that improved herbicide incorporation and<br />slower release were linked to potential interactions between the herbicide and the polymer.<br />

--

SOUTHWEST UNIVERSITY