| Abstract: | Polymer membranes loaded with agrochemicals are used as controlled release monolithic dispensers in pest control. Plasticized poly(vinyl chloride) dispensers loaded with a fixed concentration of gossyplure pheromone were prepared by a solution-casting method. A solvent trap system was designed and fabricated to collect the gossyplure released from the dispenser at desired intervals of time. The release of pheromone was estimated quantitatively by using high-performance liquid chromatography. The rate of release is found to be slightly higher in the first 12 h and then it became steady, obeying Fick's law of diffusion. The diffusion coefficient of the pheromone is observed to be directly proportional to the concentration of the plasticizer in the dispenser. Simultaneously, the rate of release of pheromone from the dispenser was also determined by a gravimetric desorption method. The diffusion coefficient data obtained from the gravimetric desorption method was found to be fairly comparable to that obtained from high-performance liquid chromatographic estimation. The results indicate the authenticity and reliability of the gravimetric desorption method. The dispensers were found to release gossyplure at reasonably controlled rates even after 30 days. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 64: 1373–1380, 1997 |
