Physical property testing of a novel hybrid natural rubber-graft-cassava starch/sodium alginate bead for encapsulating herbicide

A novel bead of modified starch for encapsulating 2,4-dichlorophenoxy acetate (2,4 DA) was made from natural rubber-graft-cassava starch (NS) and sodium alginate (SA) in a water-based system. The particle size and zeta potential of pristine NS, the NS/SA blend and the NS/SA blend containing 2,4 DA were evaluated. The swelling ratio in water of the beads was investigated and found to be enhanced as a function of the SA portion in the hydrogel due to an increase in the hydrophilic groups in the beads. In addition, the chemical interaction between 2,4 DA and the polymer matrix was investigated by FTIR and XRD. The results suggest that an NS/SA matrix is a good polymer membrane for encapsulating 2,4 DA in a water medium and the beads are also easily decomposed in the natural environment after use.