510 research outputs found

    Design of modified plastic surfaces for antimicrobial applications: Impact of ionizing radiation on the physical and mechanical properties of polypropylene

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    Surface modification of polypropylene (PP) sheets was carried out by radiation induced graft polymer- ization of hydrophilic functional molecules such as N,N-dimethylacrylamide (DMA) and [2-methacry- loyloxy)ethyl] trimethylammonium chloride, which is a quaternary ammonium salt (QAS). Polypropylene sheets were activated prior to the grafting reaction by using electron beam radiation. The changes in morphology, crystallinity and tensile parameters like deformation and stress at yield and deformation at break of PP after irradiation were investigated. The results showed that a minor crystalline reorganization takes place during the irradiation of PP at 100 kGy. The grafting has been observed to be strongly dependent on the monomer dilution in the reaction medium. After grafting of QAS (40%) and DMA (20%) it was possible to develop highly hydrophilic surfaces (water contact angle comprised between 30 and 411). The surfaces of virgin, irradiated and grafted PP were studied using polarized optical microscopy (POM) and scanning electron microscopy (SEM). Spherical particles (i.e. polystyrene or silica beads) adhering to the modified samples were studied according to the surface parameters. Adhesion tests confirmed the strong influence of substrate type (mainly hydrophilicity and roughness) and to a lesser extent underlined the role of electrostatic interactions for the design of plastic surfaces for antimicrobial applications

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    Programme de l’année 2014-2015 : I. Les archives économiques du monastère de Baouit. — II. Étude des textes oraculaires d’Antinoé

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    Programme de l’année 2018-2019 : I. L’épigraphie funéraire chrétienne d’Égypte et de Nubie. — II. Documents juridiques de Moyenne-Égypte (suite)

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    Programme de l’année 2014-2015 : I. Les archives économiques du monastère de Baouit. — II. Étude des textes oraculaires d’Antinoé

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    Programme de l’année 2015-2016 : I. Déplacements et circulation dans la région thébaine. — II. Documents coptes d’Edfou

    Chapter Un contrat de travail atypique d’Antinoupolis

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    Chapter Corrections à quelques documents de Vienne

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    Programme de l’année 2019-2020 : I. L’épigraphie funéraire chrétienne d’Égypte et de Nubie (suite). — II. Documents juridiques de Moyenne-Égypte (suite)
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