R. Schmid1, A. D. Dyrli2, K. Olafsen1, and Ø. Antonsen3
1SINTEF Materials and Chemistry, N-7465 Trondheim, Norway; 2Resman AS, N-7041 Trondheim, Norway, 3NetKem AS, N-1410 Kolbotn, Norway
Both stable oily and aqueous dispersions of Bitrex®-containing brittle crosslinked polymeric microspheres, either from polyacrylamide or polystyrene could be prepared by respectively w/o emulsion or w/o/w double emulsion processes. Only aqueous dispersions from double emulsions with non-ionic stabilizers in the outermost water-phase could be successfully mixed into commercial impregnating formulations and applied to pieces of fish farming nets. Up to now, it could be shown, that Bitrex® may be encapsulated in brittle microspheres to hinder rapid leaking out when applied to the nets, opening for triggered release during gnawing and nibbling and prolonged time-interval between impregnations. Results from field tests are not yet available. Further optimization of the preparation process, as well as testing of other capsule materials and bitter flavoring agents is planned.