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Carbon nanotubes (CNTs) have been dispersed within polypropylene with the purpose to prepare electromagnetic interference (EMI) absorbers. In order to limit the reflectivity of the electromagnetic waves at the interface of the materials while achieving good absorbing properties, the CNTs concentration must be kept low (<3 wt%) which means that a perfect dispersion must be ensured. Since CNTs do...
A straightforward strategy is proposed to impart antimicrobial properties to biodegradable poly(oxepan-2-one) (poly(ɛ-caprolactone) or PCL), which is based on the grafting of pendant ammonium salts by “click” chemistry. First, statistical copolymerization of 3-chlorooxepan-2-one (α-chloro-ɛ-caprolactone or αClɛCL) with oxepan-2-one (ɛ-caprolactone or ɛCL) was initiated by 2,2-dibutyl-2-stanna-1,3-dioxepane...
Gold nanoparticles (NPs) were prepared by reduction of HAuCl 4 in aqueous solution and stabilized by poly(N-isopropylacrylamide) (PNIPAM). PNIPAM was prepared by two distinct routes: (i) conventional free-radical polymerization leading to polymer without any reactive end-group, and (ii) Reversible Addition–Fragmentation chain Transfer (RAFT) polymerization with 2-dodecylsulfanylthiocarbonylsulfanyl-2-methyl...
Copper-mediated azide–alkyne Huisgen's 1,3-dipolar cycloaddition is a “click” reaction that was successfully used to prepare pH-responsive, amphiphilic and biodegradable networks. Indeed, this reaction proved to be very efficient in the “one pot” grafting of amino alkyne onto azide containing poly(ɛ-caprolactone) and the cross-linking of these chains by α,ω-dialkynyl poly(ethylene oxide). The pH-controlled...
Star-shaped polymers with a fullerene (C 60 ) core and an unexpanded structure were successfully prepared by reaction of C 60 with amino end-capped polyesters H x C 60 (NHPCL n ) x and polyethers H x C 60 (NHPEG n ) x , respectively. Upon irradiation of these C 60 -derivatives, a large amount of singlet oxygen...
Synthesis of an asymmetric tadpole-shaped aliphatic copolyester consisting of a poly(ɛ-caprolactone) ring and two poly(l-lactide) tails was reported for the first time. First, a high molecular weight cyclic PCL macroinitiator (M n =31,000) was prepared by intramolecular photocross-linking of “living” chains. Polymerization of l-lactide was resumed by the tin dialkoxide containing macrocycles,...
The poly(styrene)-block-poly(2-vinylpyridine)-block-poly(ethylene oxide) triblock copolymer, PS 200 -b-P2VP 140 -b-PEO 590 , where the subscripts refer to the average degrees of polymerisation of the constitutive blocks, has been dissolved in water/toluene mixtures with a large range of composition, i.e. in (i) toluene added with a small amount of water, (ii) water-in-toluene...
The counter-ions of montmorillonite have been exchanged for ammonium cations containing either a sulfonic acid or a carboxylic acid in order to improve the performances of sulfonated membranes in direct methanol fuel cell. These layered silicates have been dispersed within Nafion ® by solution mixing. Comparison with conventional organo-modified montmorillonite (Cloisite 30B) shows that the...
Thermo-sensitive nanosized structures have been prepared in water from poly(methyl vinyl ether)-block-poly(isobutyl vinyl ether) (PMVE-b-PIBVE) block copolymers. The composition and the architecture (diblock and triblock architectures) of the PMVE-b-PIBVE copolymers have been varied. The investigated copolymers had an asymmetric composition with a major PMVE block. While the PIBVE blocks are hydrophobic,...
Poly(ε-caprolactone)/montmorillonite nanocomposites, prepared by bulk ring-opening polymerization of ε-caprolactone in the presence of tin(II) 2-ethylhexanoate as a catalyst and hydroxy groups of ammonium tethers of organoclay acting as chain-growth centers, were characterized by the stretching calorimetry technique.In the range of elastic (reversible) deformations, experimental Young's moduli and...
Poly(ethylene oxide) (PEO) end-capped by a methacrylate unsaturation was copolymerized with acrylic acid by RAFT with dibenzyltrithiocarbonate as a chain transfer agent. Tapered triblock copolymers consisting of a poly(acrylic acid) (PAA) inner block and comb-like outer blocks of PEO macromomers were formed as result of the comonomers reactivity ratios. Composition of these copolymers and length of...
Multi-walled carbon nanotubes (MWNTs) have been successfully modified by polystyrene, poly(ɛ-caprolactone), and their block copolymers by addition reaction of the alkoxyamine-terminated precursors. Polymer-modified MWNTs are easily dispersed in good solvents for the grafted polymer, such as toluene and THF. This observation has been confirmed by TEM analysis. The grafting ratio of polystyrene chains...
(Nano)composites of poly( -caprolactone) (PCL) were prepared by melt blending the polymer with natural Na + montmorillonite and montmorillonite modified by hydrogenated tallowalkyl (HTA)-based quaternary ammonium cations, such as dimethyl 2-ethylhexyl HTA ammonium and methyl bis(2-hydroxyethyl) HTA ammonium. Microcomposites or nanocomposites were prepared depending on whether neat or modified...
Polyethylene-layered silicate nanocomposites were prepared by the in situ intercalative polymerization of ethylene by the so-called polymerization-filling technique and analyzed by transmission electron microscopy (TEM), X-ray diffraction analysis (XRD), differential scanning calorimetry, dynamic mechanical analysis and tensile testing. Non-modified montmorillonite and hectorite were first treated...
This paper reports on an efficient 'in-situ' one pot synthesis of an initiatior/ligand adduct, which can be used to initiate the anionic polymerization of methyl methacrylate in toluene at 0 o C. Predominantly syndiotactic PMMA is formed.
The self-aggregation of a series of amphiphilic poly(methyl methacrylate)-block-poly(sulfonated glycidyl methacrylate) (PMMA-b-PSGMA) copolymers in water has been studied by dynamic light scattering (DLS), size exclusion chromatography (SEC) and surface tension measurements. All the copolymers considered in this study form micelles which, however, aggregate into larger structures as shown by DLS and...
Structure and electrical properties of conducting polyethylene/graphite composites have been studied in relation to the preparation method, i.e. (i) the polymerization-filling technique (PFT), in which the polyolefinic chains are growing from the graphite surface, (ii) the slurry polymerization of ethylene in the presence of untreated graphite, and (iii) the mechanical blending of preformed polyethylene...
Thermoplastic elastomers consisting of triblock copolymers (MBM) with outer syndiotactic poly(methyl methacrylate) (sPMMA) blocks associated to an inner polybutadiene (PBD) block have been modified by stereocomplexation with isotactic PMMA (iPMMA) at a constant 21 sPMMAiPMMA (or si) mixing ratio. Toluene cast films of these stereocomplexes have been studied by thermal analysis as a function of molecular...
A novel thermoplastic elastomer consisting of a triblock copolymer (MBM) with outer syndiotactic poly(methyl methacrylate) (sPMMA) blocks associated to an inner polybutadiene (PBD) block has been modified by stereocomplexation with isotactic PMMA (iPMMA). Solution cast films of stereocomplexes have been analysed by thermal analysis as a function of the iPMMA/sPMMA (i/s) mixing ratio and the solvent...
Syndiotactic poly(methyl methacrylate) (sPMMA)-polybutadiene (PBD)-sPMMA triblock copolymers, or MBM, have been studied in the presence of o-xylene which is a selective solvent for the central PBD block. Syndiotactic PMMA is known to self associate in o-xylene. The central PBD sequence does not prevent the self-association of sPMMA from occurring. Actually, this phenomenon contributes to the stability...
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