p-Methoxybenzyl-N-phenyl-2,2,2-trifluoroacetimidate: a versatile reagent for mild acid catalyzed etherification

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New insights on Uranium recovery from seawater and aqueous media

International audienceOceans uranium reserve of 4.5 billion tons can be the answer for the next-generation sustainable nuclear energy. However, extracting the extremely diluted uranium (3.3 ppb) is a difficult task and adsorption materials with high selectivity and uptake capacity are still to be found. Here, we propose the use of poly(4-vinyldipicolinic acid) (PVDPA) as a new highly promising polymer for uranium harvesting from seawater. PVDPA showed a uranium uptake capacity of 597 mg/g in simulated seawater conditions, even at high ionic strength and in the presence of the challenging vanadium species, that tend to limit the performance of other existing materials. PVDPA is also built from a solid PVC-based substrate using an easy and oxygen tolerant strategy. The used PVDPA-modified fibers showed a uranium uptake capacity of 392 mg/g and reached the adsorption equilibrium in less than 3 h, the fastest and highest reported, to the best of our knowledge. The cheap, easy and fast preparation, combined with fast and high uranium recovery, make PVDPA highly promising, not only for uranium harvesting from seawater, but also for treating waters contaminated with uraniu

Poly(ethylene terephthalate) films modified by UV-induced surface graft polymerization of vanillin derived monomer for antibacterial activity

International audienceNew antibacterial PET surfaces were developed from vanillin-derived biobased monomer. An easy one-step and high yielding synthesis of N-(4-hydroxy-3-methoxybenzyl)-acrylamide monomer was successfully achieved. PET was modified by a two-step procedure: Type II photoinitiator was first grafted through a PET aminolysis with N,N-diethylethylenediamine, then the photopolymerization of the biobased acrylamide monomer was performed according to a “grafting from” technique. PET surface modifications were characterized by XPS and UV–visible spectroscopies, as well as water contact angle measurements. Finally, antiadhesion biotests were conducted to evaluate the potential antibacterial performances of the modified surfaces against gram-positive (Rhodococcus wratislaviensis and Staphylococcus aureus) and gram-negative (Escherichia coli and Pseudomonas aeruginosa) strains

Copolymers Derived from Two Active Esters: Synthesis, Characterization, Thermal Properties, and Reactivity in Post-Modification

Copolymers with two distinguished reactive repeating units are of great interest, as such copolymers might open the possibility of obtaining selective and/or consequent copolymers with different chemical structures and properties. In the present work, copolymers based on two active esters (pentafluorophenyl methacrylate and p-nitrophenyl methacrylate) with varied compositions were synthesized by Cu(0)-mediated reversible deactivation radical polymerization. This polymerization technique allows the preparation of copolymers with high to quantitative conversion of both comonomers, with moderate control over dispersity (Đ = 1.3–1.7). Additionally, by in-depth study on the composition of each copolymer by various techniques including elemental analysis, NMR, FT-IR, and XPS, it was possible to confirm the coherence between expected and obtained composition. Thermal analyses by DSC and TGA were implemented to investigate the relation between copolymers’ composition and their thermal properties. Finally, an evaluation of the difference in reactivity of the two monomer moieties was confirmed by post-modification of copolymers with a primary amine and a primary alcohol as the model

Facile and efficient Cu(0)-mediated radical polymerisation of pentafluorophenyl methacrylate grafting from poly(ethylene terephthalate) film

International audienceGrafting polymers bearing active esters, especially pentafluorophenyl methacrylate (PFPMA), onto or from surface is a promising approach towards the preparation of highly functional materials due to the ease in post-polymerisation modification of their corresponding polymers. Herein, a handy and efficient chemical modification process is proposed to modify extreme surface of poly(ethylene terephthalate) (PET) films towards the final purpose of grafting PFPMA polymer from PET surface via surface-initiated Cu(0)-mediated radical polymerisation. The characteristics of modified surface were evaluated after each step using various techniques including water contact angle, attenuated total reflectance Fourier-transform infrared spectroscopy, X-ray photoelectron spectroscopy, atomic force microscopy, and scanning electron spectroscopy. Due to its robust conditions, the proposed approach allows grafting at ease PFPMA polymer from PET supporting surface, which not only enhances the reactivity of this inert material but also improves significantly the hydrophobicity of the surface

Poly(4-vinylpyridine)-modified silica for efficient oil/water separation

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Surface initiated supplemental activator and reducing agent atom transfer radical polymerization (SI-SARA-ATRP) of 4-vinylpyridine on poly(ethylene terephthalate)

International audiencePoly(ethylene terephthalate) (PET) substrates were modified by means of surface-initiated supplemental activator and reducing agent atom transfer radical polymerization (SI-SARA-ATRP) of 4-vinylpyridine (4VP). Substrates were pretreated in order to graft chloromethylbenzene (CMB) units capable of initiating the radical polymerization reaction of 4VP units. Surface characterization techniques, including Water Contact Angle (WCA), Attenuated Total Reflection (ATR), X-ray photoelectron spectroscopy (XPS), Atomic Force Microscopy (AFM) and Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS) showed a successful grafting of a stable, smooth and homogenous layer of p4VP. This process offers the advantages of a rapid, simplified and low cost strategy to chemically modify polymer substrates with covalently bonded layer of the pH responsive p4VP for different applications. Moreover, by using TOF-SIMS profiling, we were able to track a density gradient along the z-axis generated by the interpenetrating phases of the different layers of the final modified surface. Fact that we correlated to the various positions of initiation sites within the polyethylenimine (PEI) used for PET aminolysis prior to CMB grafting. Our strategy will be used in future work to graft other polymers for different applications where industrial scale viable options are needed

An eco-friendly process for the elaboration of poly(ethylene terephthalate) surfaces grafted with biobased network embedding silver nanoparticles with multiple antibacterial modes

This paper reports a strategy for the elaboration of highly performing antibacterial PET surfaces according to an eco-friendly photoinduced process. Modified PET surfaces were elaborated through the grafting of a three dimensional (3D) biopolymer derived from vanillin with antibacterial activity. Biobased polymer grafting was performed through a grafting-from photopolymerization approach initiated from a photoinitiator compound preliminary functionalized onto PET surface. Antibacterial activity of the elaborated materials was tested against Gram-positive (Rhodococcus wratislaviensis and Staphylococcus aureus) and Gram-negative (Escherichia coli and Pseudomonas aeruginosa) strains. Antibacterial activity of the biopolymer covalently linked onto PET surface was observed for all tested bacterial strains. Antibacterial effect of vanillin derivative coated onto PET material was combined with a multi-scale roughness induced through the grafting process giving antifouling behaviour to the material. Besides, to improve antibacterial activity of the modified material, biobased network was used as binding sites for photoembedding of antimicrobial silver nanoparticles. The hybrid material showed excellent antibacterial properties against Gram-positive and Gram-negative tested cells. The enhancement of material antibacterial activity against this wide range of pathogens resulted of a combination of different effects: the antibacterial activity of coated vanillin derivative and nanosilver combined with a surface nanostructuration imparting antifouling properties. Grafting of biobased polymer network loaded with nanosilver onto PET material was characterized at various stages of the modification by UV–vis spectroscopy, water contact angle measurements, scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The surface topography was studied by atomic force microscopy (AFM)

Plasma deposition of silver nanoparticles onto poly(ethylene terephthalate) surfaces for the preparation of antimicrobial materials

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Synthesis, characterization and catalytic properties of salen-containing polymers obtained by atom transfer radical polymerization

International audienceStyrene copolymers containing 5–50 mol % of a comonomer with a salen catalytic-active moiety are synthesized by using ATRP in solution. Control of the synthesis is obtained only when the salen comonomer incorporation is less than 10 mol %. In those conditions, first-order kinetics, linear increase of Mn versus time and monomodal narrow molar mass distributions with molar mass dispersities Ð in the range 1.28–1.33 are satisfactorily achieved. For copolymers with higher incorporated salen comonomer, control of the reaction progressively disappears with dispersities increasing with salen comonomer incorporation up to Ð = 1.72. Cobalt complexation of those copolymers allows high yield and selectivity in the catalysis of the dynamic hydrolytic kinetic resolution of epibromohydrin. In spite of the loss of polymerization control, the highest (50%) salen incorporation yields the best catalytic results. Under these conditions, the high concentration of Co catalytic sites might favor the formation of bimetallic complexes responsible for the high activity and enantioselectivity