Microencapsulation d’agent antimicrobien pour le développement de conditionnements primaires fonctionnalisés

Abstract : First, this work focused on the formulation of microparticles loaded with antimicrobial agent using the emulsion/solvent evaporation method. Several morphologies have been obtained with nonsmooth microparticles characterized by scars and defects, roughness and holes. The parameters and the physico-chemical mechanisms involved in these morphological deteriorations have been identified and discussed. It has been shown that the formulation and processing parameters as the polymer mass and molar mass, the surfactant as well as the speed and shear rate of the propeller play a key role in the final microparticles surface states. This study proved that there is a competition between solvent evaporation and the coalescence of emulsion droplets which is responsible for the morphological degradations. Following this study, the resulting microspheres loaded with phenylethyl alcohol were dispersed in a binder and coated as thin films of various thicknesses by the dip-coating method at the polyolefin surface. It has been measured that the use of microparticles slows the antimicrobial agent diffusion by increasing the number of polymeric matrices that have to be crossed in order to reach the external medium. Such thin films resulted in an antimicrobial agent delivery up to 3 months which is 15 times higher than the delivery obtained for the non-encapsulated antimicrobial agent. The antimicrobial activity of the phenylethyl alcohol in an emulsion has also been investigated. The phenylethyl alcohol partition between the water phase, the oil phase and the micellar phase of an emulsion has been measured. These results led to the development of a mathematical model calculating the fraction of free antimicrobial agent present in the aqueous phase. It has been correlated with emulsion dosages and microbiological measurements using the five microorganisms of the challenge test during 14 days. It has been demonstrated that calculations enable the prediction of the antimicrobial agent concentration needed to ensure the antimicrobial protection. In particular, this work proved that the phenylethyl alcohol quantity necessary for antimicrobial protection is respectively 1.6 and 4.3 times higher for a micellar solution and an emulsion compared to an aqueous solution
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  • HAL Id : tel-01267568, version 1



Jessica Bile. Microencapsulation d’agent antimicrobien pour le développement de conditionnements primaires fonctionnalisés. Chimie théorique et/ou physique. Université Claude Bernard - Lyon I, 2015. Français. ⟨NNT : 2015LYO10182⟩. ⟨tel-01267568⟩



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