Polysaccharides are complex but essential compounds utilized in many areas such as biomaterials, drug delivery, cosmetics, food chemistry or renewable energy. Modifications and functionalizations of such polymers are often necessary to achieve molecular structures of interest. In this area, the emergence of the "click" chemistry concept, and particularly the copper-catalyzed version of the Huisgen 1,3-dipolar cycloaddition reaction between terminal acetylenes and azides, had an impact on the polysaccharides chemistry. The present review summarizes the contribution of "click" chemistry in the world of polysaccharides.

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International audienceCyclodextrins are important building blocks in organic chemistry. This review deals with the role of click chemistry in this family of cyclic oligosaccharides, focusing on the different areas of chemistry, including chromatography, biological applications, the elaboration of superstructures, and metal detection, that benefit from this reaction. In this paper, attention is given to organic modifications by using functionalizations such as azidation and propargylation and to click chemistry grafting onto the two faces of cyclodextrins. Research papers where cyclodextrins are not directly involved in a click chemistry reaction are not considered

International audienceThis study aims to present structural and dielectric comparisons between two epoxy polymers. These polymers are realized by curing diglycidyl ether of bisphenol A (DGEBA) resin with either aliphatic 1,3-diaminopropane (PDA) or aromatic 4,4′-diaminodiphenyl sulfone (DDS) hardeners. They are called DGEBA/PDA and DGEBA/DDS. Several complementary techniques have been used in the present study. The structural analysis was performed using grazing incidence X-ray reflectometry. It reveals the presence of a locally ordered nanostructure in the DGEBA/DDS polymer and an amorphous character for the DGEBA/PDA one. Dielectric characterization was carried by means of dielectric relaxation spectroscopy (DRS), thermally stimulated depolarization current (TSDC) and time domain spectroscopy (TDS). DRS measurements performed over wide ranges of temperature (−80 to 160 °C) and frequency (10−1–106 Hz) showed the presence of dipolar γ and α relaxations in both polymers. Nevertheless, the interfacial Maxwell–Wagner–Sillars (MWS) relaxation appeared only in DGEBA/DDS. This can be related to the local nanostructure within this polymer, which can give rise to interfaces. Relaxation parameters were deduced from the best fits of experimental data with the Havriliak–Negami model. The calculated fragility index indicates that DGEBA/DDS is more fragile than DGEBA/PDA. The loss factor ε′′(f) was calculated from the isothermal discharging current measurements, using Hamon approximation. Thanks to this ε′′ calculation an interfacial relaxation was revealed in the frequency range of 10−3–10−1 Hz for each investigated polymer

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International audiencep-Toluenesulfonyl cellulose was prepared by reacting cellulose in aqueous medium, instead of via traditional routes, which involve the use of DMAc/LiCl, or more recently, ionic liquids. The influence of several parameters on the reaction efficiency has been studied; amount of tosylchloride, presence of triethylamine, reaction time and use of sodium hydroxide or sodium chloride. The resulting p-toluenesulfonyl cellulose samples were characterized by means of FTIR and NMR spectroscopy. The effects of solvent on the crystalline change during tosylation were investigated by X-ray diffraction (XRD). The degree of substitution (DS) was determined by 1H NMR and confirmed by X-ray photoelectron spectroscopy (XPS). Tosylcelluloses with DS from 0.1 to 1.7 have been prepared