Abstract

The aim of this study is to obtain a biodegradable, inexpensive and highly water- swellable agricultural hydrogel by radical copolymerization of a starch-chitosan (St-g-CTS) hybrid with acrylic acid (AA). When examining the synthesized ((St/СTS)/PAA) based hydrogel using a scanning electron microscope (SEM), it was found that it has pores necessary for absorption and desorption. IR spectroscopy and differential thermogravimetric analyzes of the obtained hydrogels are investigated. The water absorption of the resulting hydrogels in distilled water and saline solutions of various concentrations was determined. Swelling in distilled water was 550 g/g, in saline solutions 60 to 127 g/g (0.9% saline solution). The dependence of the degree of swelling of the synthesized superabsorbent hydrogels on the molar ratio of starch, chitosan and acrylic acid, the amount of initiator and binder, the duration and temperature of the reaction has been determined. The use of synthesized hydrogel in agriculture helps to reduce the consumption of irrigation water, reduces the drying of plants, ensures the retention of fertilizers in the soil around the roots, and increases the growth rate and productivity of plants.

Key words: Starch-chitosan, vinyl monomer, copolymerization, water absorption, acrylic acid grafting.