Effect of Cross-linking Time on Sodium Alginate Based Blend Films as a Supporter of Bordeaux Mixture

Blend films based on sodium alginate (SA) are synthesized and the use of these films as a supporter for Bordeaux mixture to adhere the crops for longer time and sustained release of active ingredient were studied. An aqueous solution of Sodium alginate was prepared and the obtained solution was added to bordeaux mixture of fixed compositions. Alginate solution is cross-linked by the multivalent cations present in bordeaux mixture and forms films. Blends based on sodium alginate with gelatin(SAGN) and sodium alginate with guar gum(SAGM) were synthesised. The thickening and cross linking action of these films were controlled by varying the cross linking time. The films were dried at 50oC in an oven and kept in different buffer solutions for swelling studies. From the swelling data, rate and kinetics of swelling were studied and swelling parameters were tabulated. The swelling parameters showed that the various bordeaux mixture cross-linked films were stable and they can absorb sufficient quantity of water and may prevent leaching out of active ingredients on rough weathers. Also the cross-linked polymer film may serve in increasing life and sustained release of active ingredients.

Keywords: Blends, Bordeaux mixture, ionic cross linking, pH sensitivity, sustained release