Controlled release of biocide from silica microparticles in wood paint

Porous microparticles represent an attractive encapsulation platform as they provide a feasible route to a wide range of encapsulated chemical compounds. This assures an increased lifetime of the encapsulated compound by protecting it from the surrounding environment as well as providing a way to control the release rate. Porous microparticles encapsulating the commonly used biocide for wood protection, 3-iodoprop-2-ynyl N-butylcarbamate (IPBC), have been synthesized. The microparticles are spherical with an average size distribution of roughly 1 μm as determined by scanning electron microscopy (SEM). Determination of the release rate of the biocide from microcapsules incorporated into the paint film has been performed under diluted conditions. These experiments show that a slower release of the biocide can be obtained by encapsulation. Additionally, the microparticles have been shown to prolong the biocidal effect of the fungicide under accelerated weathering tests by protecting the biocide from UV-induced chemical degradation.