Amphiphilic chitosan/acrylic acid/thiourea based semi-interpenetrating hydrogel: Solvothermal synthesis and evaluation for controlled release of organophosphate pesticide, triazophos

The current study reports the solvothermal synthesis of amphiphilic chitosan-based semi-interpenetrating (CAT-SIPH) hydrogel for controlled release of an organophosphate pesticide, triazophos. CAT-SIPH is prepared from natural backbone polymer chitosan (CS) and monomer, acrylic acid (AA) employing initiator (K2S2O8), and cross-linker, thiourea (CSN2H4) using solvothermal technique under 7 Psi pressure in an autoclave. The polymerization reaction variables like reaction time, the volume of solvent, concentration of initiator, cross-linker, and monomer are optimized to get the best product yield in terms of percentage grafting. The optimized conditions for solvothermal polymerization reaction carried out for 60 min are solvent volume (10 ml), concentrations of acrylic acid (0.2 mol/L), K2S2O8 (0.45 x 10(-2)mol/L) and thiourea (1.75 x 10(-4) mol/L). The swelling behavior of CAT-SIPH hydrogel synthesized under optimized conditions is studied in the terms of swelling ratio. CAT-SIPH is characterized by Fourier transform infrared spectra (FT-IR), (HNMR)-H-I, thermal analysis (TA), Zeta potential, and scanning electron microscopy (SEM). The potential of cross-linked hydrogel CAT-SIPH for controlled release of an organophosphate pesticide, Triazophos on to sandy loam soil is assessed. The experimental investigations proved that synthesized hydrogel can be effectively employed as a pesticide carrier for controlled release on to loamy soil as the maximum release (53%) is observed even after 25 days at pH 6 and value get lowered under acidic and basic conditions. The present investigation demonstrated the potential of chitosan-based CAT-SIPH hydrogel as a pH-responsive release vehicle for agrochemicals onto the soil matrix and offers a potential solution for the prevention of surface and groundwater contamination.

Automated summary

This study demonstrates the solvothermal synthesis of amphiphilic chitosan-based semi-interpenetrating (CAT-SIPH) hydrogel for controlled release of the organophosphate pesticide, triazophos. The optimized CAT-SIPH hydrogel exhibits promising swelling behavior and is effective as a pesticide carrier for controlled release onto loamy soil.