STUDIES ON SOME CONDENSATION POLYMERS FOR CONTROLLED-RELEASE OF HERBICIDES

Monomeric herbicides of diethanolamine derivatives were prepared from diethanolamine and 2,4-dichlorophenoxyacetic and 4-chloro-2-methylphen oxyacetic acids. The melt polycondensation reactions of the monomeric diethanolamine derivatives with dicarboxylic acids afforded the corres ponding herbicide polyesters. However, the solution polycondensation t echnique was used in the preparation of the herbicide-polyurethane der ivatives by the reaction of diethanolamine derivatives with HMDI. Intr oduction of different ratios of crosslinker into the linear polymers w as achieved by subjecting them to reactions with different ratios of H MDI (5 and 10%) to afford swellable polymeric materials. Furthermore, the preformed amine-containing polyester of hydroquinol-diacetic acid was also modified with 2,4-dichlorophenoxyacetic acid. The produced mo nomers, polyesters, and polyurethanes were characterized by various ph ysical techniques. The hydrolyses of 2,4-dichlorophenoxyacetic acid fr om polymeric herbicides were carried out under different simulated con ditions. The amounts of the released herbicide were evaluated by measu ring the UV absorbance of the supernatant solution at different period s of time.