The Raman spectrum of a Nafion 117 membrane immersed in aqueous solution was recorded. Assignments are proposed for the fundamental vibrations observed for this material. The interaction of counter ions (cations) and also of sorbed electrolytes with the antagonist group SO,-of the membrane were studied. For this purpose, intensity measurements were made of selected appropriate signals versus the nature and type of counter ions (monovalent, divalent). The intensity of the symmetric stretching vibration band of the SO,-group can be used to monitor the variation of the conductivity of the membrane studied.

Industrial membranes (made of plyacrylic acid chains grafted onto a polyethylene matrix), immersed in heavy water, were studied by Raman spectroscopy. The homogeneity of the graft density was sufficient to permit the determination of relative graft ratios of different samples. Plots of measured ionization versus the pH of solutions in equilibrium with immersed membranes led to intrinsic pK determinations. For this kind of membrane, it was established that the average lengths of the plyacrylic chains are of the same order of magnitude. Consequently, the different graft ratios depend only on graft density.

Grey mould is a major disease threatening the Moroccan tomato; this disease is often controlled by fungicides. However, the latter are a real danger to human health and environment. Thus, this study is part of the research of harmless alternatives such extracts of aromatic and medicinal plants (Lavandula officinalis, Thymus vulgaris, Cymbopogon citratus, and Melissa officinalis). In this study, the extracts of four medicinal and aromatic plants were tested for their antifungal potency in vitro and in vivo in order to select the most effective. The results show that, in vitro, the Lavandula officinalis, Thymus vulgaris and Cymbopogon citratus aqueous extracts all possess significant antifungal activity, whereas Melissa officinalis shows the least effective. Also in vivo only the aqueous extract of Cymbopogon citratus proves most effective against B. cinerea on tomato fruit. The test of the plants confirms that aqueous extracts of Cymbopogon citratus and Thymus vulgaris are most effective, while the aqueous extracts of Melissa officinalis and Lavandula officinalis always seem to be the least effective. Therefore, the aqueous extracts of Cymbopogon citratus and Thymus vulgaris are the most envisaged for the biological control of grey mould.

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