COMPARATIVE-STUDY OF RELEASE KINETICS OF PHEROMONE FROM POLYMER DISPENSERS

Polymer membranes loaded with agrochemicals are used as controlled rel ease monolithic dispensers in pest control. Plasticized poly(vinyl chl oride) dispensers loaded with a fixed concentration of gossyplure pher omone were prepared by a solution-casting method. A solvent trap syste m was designed and fabricated to collect the gossyplure released from the dispenser at desired intervals of time. The release of pheromone w as estimated quantitatively by using high-performance liquid chromatog raphy. The rate of release is found to be slightly higher in the first 12 h and then it became steady, obeying Ficks law of diffusion. The d iffusion coefficient of the pheromone is observed to be directly propo rtional to the concentration of the plasticizer in the dispenser. Simu ltaneously, the rate of release of pheromone from the dispenser was al so determined by a gravimetric desorption method. The diffusion coeffi cient data obtained from the gravimetric desorption method was found t o be fairly comparable to that obtained from high-performance liquid c hromatographic estimation. The results indicate the authenticity and r eliability of the gravimetric desorption method. The dispensers were f ound to release gossyplure at reasonably controlled rates even after 3 0 days. (C) 1997 John Wiley & Sons, Inc.