Physico-Chemical, Rheological, and Viscoelastic Properties of Starch Bio-Based Materials

International audienceThis study describes the elaboration and characterization of plasticized starch composites based on lignocellulosic fibers. The transformation of native to plasticized starch (TPS) and the preparation of TPS blends were performed with a new lab-scale mixer based on an original concept. Firstly, the morphology and chemical composition of flax shives were analyzed to better understand the intrinsic properties of these natural fillers. Then, the impact of the processing parameters (temperature, speed screw) on the quality and the structural properties of plasticized starch were examined by SEM and DRX. After that, we focused on the elaboration of various formulations based on plasticized starch matrix by varying TPS formulation and filler content (from 10 to 30%). The viscoelastic and rheological properties of TPS/flax blends have been analyzed by TGA, SEM, and DMTA

Polymerization and Characterization of PMMA. Polymer Chemistry Laboratory Experiments for Undergraduate Students

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Morphologie et rhéologie de biocomposites à base d’amidon plastifié en écoulement élongationnel RMX

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Morphologie et rhéologie de biocomposites à base d’amidon plastifié en écoulement élongationnel RMX

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Self-assembly and hydrophobic clusters of amphiphilic polysaccharides

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Stabilization of membranes upon interaction of amphipathic polymers with membrane proteins

Amphipathic polymers derived from polysaccharides, namely hydrophobically modified pullulans, were previously suggested to be useful as polymeric substitutes of ordinary surfactants for efficient and structure-conserving solubilization of membrane proteins, and one such polymer, 18C10, was optimized for solubilization of proteins derived from bacterial outer membranes (Duval-Terrié et al. 2003). We asked whether a similar ability to solubilize proteins could also be demonstrated in eukaryotic membranes, namely sarcoplasmic reticulum (SR) fragments, the major protein of which is SERCA1a, an integral membrane protein with Ca2+-dependent ATPase and Ca2+-pumping activity. We found that 18C10-mediated solubilization of these SR membranes did not occur. Simultaneously, however, we found that low amounts of this hydrophobically modified pullulan were very efficient at preventing long-term aggregation of these SR membranes. This presumably occurred because the negatively charged polymer coated the membranous vesicles with a hydrophilic corona (a property shared by many other amphipathic polymers), and thus minimized their flocculation. Reminiscent of the old Arabic gum, which stabilizes Indian ink by coating charcoal particles, the newly designed amphipathic polymers might therefore unintentionally prove useful also for stabilization of membrane suspensions

Agromatériaux à base de farine de blé renforcés par des fibres de coton

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