Agronomic Performances of biodegradable films as an alternative to polyethylene mulches in vineyards

International audienc

Agronomic Performances of biodegradable films as an alternative to polyethylene mulches in vineyards

International audienc

Overview of current methodologies and standards for assessing plastic biodegradation

International audienc

Overview of current methodologies and standards for assessing plastic biodegradation

International audienc

Overview of current methodologies and standards for assessing plastic biodegradation

International audienc

Polymères rapidement biodégradables

Date de publication : 10 janvier 2018 Mots-clés biosourcé | Biopolymère | BiodégradationInternational audienceSome materials can undergo fast natural decomposition by being consumed by bacteria, fungi or algae. This end of life can thus be considered as an alternative to recycling or incineration. This article starts with a description of the biodegradation process, focusing on the different steps, reactions and factors involved together with the main measuring methods. Different biodegradable materials derived from natural or artificial polymers are then presented together with their industrial applications.Certains matériaux ont la possibilité de subir une décomposition naturelle rapide en étant «consommés» par des bactéries, des champignons, des algues, des insectes, etc. C'est donc une alternative au mode de valorisation par recyclage (et donc de récupération d'énergie). Cet article se propose tout d’abord d’expliciter les étapes de la biodégradation en détaillant les principales réactions, les facteurs impliqués ainsi que les méthodes de mesure utilisées sont ensuite présentés les différents matériaux biodégradables issus de polymères naturels ou artificiels, et les principales applications industrielles des polymères biodégradables

Protein/Clay Nano-Biocomposites

International audienceIn the current context, protein-based materials might be considered as an alternative to the petroleum-based plastics since fully biodegradable and characterized by remarkable functional properties that can be exploited in a wide range of non-food applications. To improve their performances that are often restricted by high water sensitivity and low mechanical properties, a relevant strategy consisted in the development of protein/clay nanocomposite. For this purpose, several examples of protein-based nano-biocomposites were presented with a special attention for the methods used for the incorporation of layered silicates (organically modified or not) into the matrices and the ultimate functional properties exhibited by the resulting materials. In terms of mechanical properties, the addition of nanoclays leads to a significant improvement of material performance with an increase of Young’s modulus and tensile strength ranging between 1.5 and 2 times. As regards as barrier properties, the improvement appeared quite moderate in spite of a rather good dispersion of layered silicates that would be expected to result in a tortuous pathway limiting diffusion of gases molecules. Thus, a two-fold reduction in water vapour permeability was obtained, and the same or no effect in the case of permeability toward O2 and CO2

Micellar Transition State in Casein Between pH 5.5 and 5.0

International audiencepH-induced changes in casein micelles during direct acidification and bacterial fermentation of reconstituted skim milk at 20ЊC were monitored by scanning electron microscopy (SEM) in combination with biochemical and rheological methods. For SEM casein micelle observations, an original method of milk sample preparation with porous inorganic membranes was developed. Micrographs suggested that different stages of micellar association were related to pH and that between pH 5.5 and 5.0 casein micelles coalesced. Correlations between microstructural and biochemical changes in casein micelles, and rheological behavior of milk or gel, help to explain the different steps leading to the final protein network of the acid milk gel

Impact of high pressure treatment on the structure of montmorillonite

International audienceThe modification of sodium montmorillonite after a high pressure pasteurization treatment was followed by X-ray diffraction, FTIR spectroscopy and thermogravimetric analysis. Regardless of the treatment intensity (300 and 800 MPa), the structure of montmorillonite was clearly modified. Such changes should be taken into consideration when binging montmorillonite polymer nanocomposites into contact with food