On the interest of using degradable fillers in co-ground composite materials

The article presents the results of a study whose objective is to show the interest of using vegetable and biodegradable fillers in composite materials. The incorporation of fillers made up of starch in the synthetic polymeric matrix was carried out by co-grinding, a process supporting the dispersion of one component in another one and thus supporting the homogeneity of the composite properties. The follow-up of the particle size and morphology has permitted to identify how the composite is formed. We could note that co-grinding makes it possible to improve the mechanical properties of the composite material, not only through a better dispersion of the filler in the matrix, but also thanks to a modification of the interface properties. Finally a study on the material degradation in water has shown that the incorporation of a vegetable, degradable and cheap filler in the synthetic matrix and the application of co-grinding during an adapted time offer interesting water-resistant properties

Intérêt d'utiliser des charges végétales dans des matériaux composites co-broyés

L’article présente les résultats d’une étude visant à montrer l’intérêt de mettre en oeuvre une charge végétale, biodégradable, dans les matériaux composites. L’incorporation de la charge constituée d’amidon, dans la matrice polymère a été effectuée par co-broyage, procédé favorisant la dispersion d’un constituant dans l’autre et favorisant ainsi l’homogénéité des propriétés du composite. Le suivi de la taille des particules et de leurs morphologies a permis d’identifier comment le composite est formé. Nous avons pu constater que le co-broyage permet d’améliorer les propriétés mécaniques du matériau, non seulement de par l’amélioration de la dispersion de la charge dans la matrice, mais aussi grâce à une modification des propriétés de l’interface

Caractérisation des propriétés mécaniques et des propriétés de surface de matériaux composites synthétisés par co-broyage en voie sèche

Cette contribution présente les résultats d’une étude sur les propriétés mécaniques et de surface d’un système particulaire constitué de poly(acétate de vinyle) (la matrice) et de carbonate de calcium (la charge) préparé par co-broyage des deux produits dans un broyeur à boulets fonctionnant en voie sèche. Le suivi de la taille a permis de définir le mécanisme de fabrication du composite obtenu par co-broyage. Les propriétés mécaniques du composite varient au cours du broyage et sont étroitement liées à l’évolution des propriétés de surface

Production of PVAc–starch composite materials by co-grinding — Influence of the amylopectin to amylose ratio on the properties

Mixtures of polyvinyl acetate (PVAc) filled with two starch types containing different amylopectin to amylose ratios were co-ground in a laboratory tumbling ball mill. The influence of the starch nature and of the co-grinding treatment on the production mechanism and on the composite properties was studied. The thermal and mechanical properties were characterized, as well as the behavior in water. The presence of starch in the mixture reduces agglomeration phenomena between matrix particles, as well as the mobility of polymeric chains. While a simple mixing of the constituents generates starch concentration points in the matrix, co-grinding favors filler dispersion and PVAc–starch interactions enabling an increase of the mixture properties without adding any chemical agent. The amylopectin to amylose ratio does not affect significantly mechanical properties while a high amylopectin rate promotes water uptake

Mechanical properties and degradation of starch-filled polystyrene coground composites

A vegetable biodegradable filler was incorporated in a synthetic matrix to produce composite materials, using a co-grinding process. This process permits a better dispersion of the filler in the matrix and better interactions at the materials interface. The mechanical properties of the as-produced composite are slightly better than those of blends, and are not significantly enhanced compared to those of the matrix alone, but this process permits to reduce the consumption of synthetic polymers. Moreover, an adapted co-grinding time permits to offer good water-resistant properties to the composite compared to blends

On the interest of using degradable fillers in co-ground composite materials

International audienceThe article presents the results of a study whose objective is to show the interest of using vegetable and biodegradable fillers in composite materials. The incorporation of fillers made up of starch in the synthetic polymeric matrix was carried out by co-grinding, a process supporting the dispersion of one component in another one and thus supporting the homogeneity of the composite properties. The follow-up of the particle size and morphology has permitted to identify how the composite is formed. We could note that co-grinding makes it possible to improve the mechanical properties of the composite material, not only through a better dispersion of the filler in the matrix, but also thanks to a modification of the interface properties. Finally a study on the material degradation in water has shown that the incorporation of a vegetable, degradable and cheap filler in the synthetic matrix and the application of co-grinding during an adapted time offer interesting water-resistant properties

Dynamic mechanical analysis of the multiple glass transitions of plasticized wheat gluten biopolymer

Glass transition of thermo-molded biomaterials made from wheat gluten and its main protein classes is studied by dynamic mechanical analysis (DMA). The materials are plasticized with variable contents of glycerol (30-40 wt %) and water (0-20 wt %). For all materials, three successive relaxation phases are systematically detected. Their positions shift to lower temperature as the plasticizer content of materials increases. Composition in gluten, glycerol and water of each relaxation phase is estimated using the Couchman-Karasz model. Irrespective of the plasticizer content or composition, the relaxation phases shows rather constant plasticizer volume fractions. The low-, middle-, and high relaxation phases include respectively around 30, 60 and 80 vol % of gluten protein. These relaxations are assigned to the segmental motion of the surface amino-acid side groups, to the collective motion of packed gluten proteins, and to the gain in protein conformational mobility as a 2D network of interacting plasticizer molecules forms

Competitive adsorption of phenol and heavy metal ions onto titanium dioxide (Dugussa P25)

International audienc

Ice-templated freeze-dried cryogels from tunicate cellulose nanocrystals with high specific surface area and anisotropic morphological and mechanical properties

International audienc

Optimization of the preparation of aqueous suspensions of waxy maize starch nanocrystals using a response surface methodology

International audienceResponse surface methodology was used to investigate the effect of five selected factors on the selective H2SO4 hydrolysis of waxy maize starch granules. These predictors were temperature, acid concentration, starch concentration, hydrolysis duration, and stirring speed. The goal of this study was to optimize the preparation of aqueous suspensions of starch nanocrystals, i.e., to determine the operative conditions leading to the smallest size of insoluble hydrolyzed residue within the shortest time and with the highest yield. Therefore empirical models were elaborated for the hydrolysis yield and the size of the insoluble residues using a central composite face design involving 31 trials. They allowed us to show that it was possible to obtain starch nanocrystals after only 5 days of H2SO4 hydrolysis with a yield of 15 wt % and having the same shape as those obtained from the classical procedure after 40 days of HCl treatment, with a yield of 0.5 wt %