Uneven distribution of nanoparticles in immiscible fluids: Morphology development in polymer blends

AbstractThe present review aims at summarizing the current knowledge on how solid nanoparticles organize in polymer blends. First, the behavior of low viscosity fluid emulsions containing solid colloidal particles is briefly presented. By contrast with polymer blends, they have been the subject of intensive studies for a long time, with both applicative and comprehensive objectives. High viscosity fluid emulsions like polymer blends loaded with nanofillers have received less attention until the recent enthusiasm about nanotechnology and more specifically polymer nanocomposites. Some similarities and differences between both types of emulsions are highlighted. The solid particles are well known to distribute unevenly in those types of complex fluids and the factors that determine their distribution in polymer blends are discussed. A particular emphasis is given on the competition between thermodynamic wetting of the solid by the polymeric phases and kinetic control of the filler localization directly linked to the rate of the mixing process. This aspect is believed to be a specificity of filled polymer blends and is known to have a drastic and sometimes predominant effect on particle localization. It explains that finely tuned morphologies can be obtained where the particles do not occupy their equilibrium position

Peste porcine classique : le cas allemand

La peste porcine classique (PPC) est une maladie très contagieuse aux répercussions sanitaires et économiques importantes. Au cours des dix dernières années, l'Allemagne, bien que premier producteur européen, n'a cessé de subir des foyers de PPC au sein de sa population de porcs domestiques. Les souches virales identifiées conjuguées aux résultats des enquêtes épidémiologiques ont permis de dégager les facteurs de risque majeurs en Allemagne. La population de sangliers infectés joue notamment un rôle déterminant dans la transmission du virus aux porcs domestiques. L'Allemagne lutte ainsi sur deux fronts avec les méthodes lui paraissant les plus adaptées : abattage total pour les porcs, chasse et vaccination orale pour les sangliers. Le bilan, favorable quant au nombre et à la localisation plus restreinte des cas, n'exclut cependant pas d'éventuelles résurgences. Parfaire les connaissances épidémiologiques et les moyens de lutte constitue l'enjeu de l'Allemagne dans la protection de sa production porcine ainsi que de celle de ses voisins européens

Etat Des Lieux Du Dispositif D’alimentation Dans Quelques Écoles Primaires De La Ville De Yaoundé (Cameroun)

School feeding refers to all the conditions through which pupils have access, choose and consume food within the school. School feeding has gained increasing attention in recent years and it is an important route in the process for achieving quality education. The availability of healthy and balanced food in schools is a necessity highlighted in many studies. In developed countries, the institutional framework for school feeding is well developed, schools have canteens, where the meals are prepared and consumed by children according to health standards. The situation is different in developing countries, especially in Cameroon where we carried out a study with an aim to have an overview of the feeding organization in some primary schools in the Yaounde I subdivision. The methodology adopted consist of a survey carried out amongst school stakeholders (school principals, teachers, students and food handlers) and visits to targeted schools. According to the results obtained, 85% of the targeted schools don’t have a building space, equipped with all the amenities (Clean water, tables, chairs, toilets) and ready to receive food vendors. Different types of foods are served to children (meals, pastries, fruits, sweets, beverages and icecreams). Unfortunately, those foods are prepared and serve under low hygienic conditions according to standards required for this purpose. Many deficiencies have been highlighted in the framework of our study and in order to mitigate them, the national government should take some actions such as the development of a national policy, the establishment of an adequate institutional framework, the development of a sustainable financing strategy and a capacity building strategy food handlers

Mediating gel formation from structurally controlled poly(electrolytes) through multiple "head-to-body" electrostatic interactions

Tuning the chain-end functionality of a short-chain cationic homopolymer, owing to the nature of the initiator used in the ATRP polymerisation step, can be used to mediate the formation of a gel of this poly(electrolyte) in water. While a neutral end group gives a solution of low viscosity, a highly homogeneous gel is obtained with a phosphonate anionic moiety, as characterized by rheometry and diffusion NMR. This novel type of supramolecular control over poly(electrolytic) gel formation could find potential use in a variety of applications in the field of electroactive materials

Relations structure-propriétés dans les polymères chargés

International audienc

Dispersion and Localization of Nanoparticles in Polymers : A Rheological Approach

International audienc

Dispersion and Localization of Nanoparticles in Polymers: A Rheological Approach

International audienc

Dispersion and Localization of Nanoparticles in Polymers : A Rheological Approach

International audienc