Development of pheromone slow release systems through microencapsulation in polymers

Synthesis of oil containing polyurea microcapsules

Study of interface properties

Encapsulation of the pheromone of the moth Sesamia Nonagrioides (Z-11-Hexadecenyl acetate) in polyurea shells

In vitro release experiments – Biological tests

Slow release processes have recently attracted an increasing attention due to their applications in diverse fields such as controlled and/or sustained release of agrochemicals, drugs, pesticides, herbicides etc. One of the most important techniques in the area of controlled release technology is the microencapsulation of active principles in different polymeric matrices by post polymerization methods or by in-situ polymerization techniques. Microencapsulation is a relatively new and rapidly expanding technology. As a process it is a means of applying relatively thin coating to small particles of solids or droplets of liquids and dispersions. The purpose is the inclusion of a substance into the polymeric microsphere.

During the reseach we attempted to penetrate the in situ polymerization and more specifically the interfacial polycondensation technique. The efforts turned to the synthesis of oil-containing polyurea microcapsules. We tried to elucidate the thickness and the morphology of the coating material, the stability of the microsphere, the importance of the emulsifier on the morphology and the size of the produced microcapsules. Different organic molecules such as pheromones were enclosed in polyurea shells and the release capability of the core material was studied. Biological tests were also carried out.

[2] P. W. Morgan, Condensation Polymers by Interfacial and Solution Methods 1965, Interscience, New York.

[3] S. K. Yadav, K. C. Khilar, A. K. Suresh, AIChE J., 1996, 9, 2616-2626.

[4] T. M. S. Chang, Science, 1964, 146, 524-525.

Sesamia Nonagrioides

Adult: 30 to 40 mm wingspan: fore wings grey-yellowish, marked with a marginal band and with rounded, indistinct points. Hind wings are entirely white.

This moth, active in the spring, attacks maize, wheat, rice, sugar cane, barley, oats, millet and less frequently asparagus and cotton.

Infected maize plants

View of microcapsule using optical microscopy

Ilias1.TGA

View of microcapsules into water.

Observe the transparency and the harsh surface of the capsules.

Ilias32.tga

Microcapsules after drying

The capsules preserve their integrity and do not break up

Xelias12.tga

Microcapsules after drying

Xelias13,22.tga