Relationship between the swelling process and the releases of water soluble agrochemicals from radiation crosslinked acrylamide/itaconic acid copolymers
An attempt was made in this study to relate the releases of water soluble herbicide (sodium 2,2 dichloropropionate (Dowpon)) and model fertilizers (ammonium nitrate, potassium nitrate and ammonium sulfate) from the cylindrical devices of radiation crosslinked poly(aclylamide/itaconic acid) (AAm/IA) copolymers with the swelling that may effect the release behaviour. AAm/IA copolymers containing agrochemicals are prepared by two different composition of itaconic acid and two different gamma -rays doses. The agrochemicals were trapped in the gels by including it in the feed mixture of radiation polymerization. The equilibrium swelling, diffusional exponent, and diffusion and intrinsic diffusion coefficients of the process were obtained. The agrochemical dissolution was determined by conductimetric method. The maximum concentrations of releasing agrochemicals and initial releasing rates were calculated by using of second order kinetics equation. The agrochemical releases appeared to be controlled by swelling. As a result, if AAm/IA hydrogels containing agrochemicals were swelled in water, release of agrochemicals was decreased with the raising of gamma -rays doses and itaconic acid quantities in the hydrogel.