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See detailFunctionalization of poly(epsilon-caprolactone) by pendant hydroxyl, carboxylic acid and epoxide groups by atom transfer radical addition
Riva, Raphaël ULg; Lenoir, Sandrine ULg; Jérôme, Robert ULg et al

in Polymer (2005), 46(19), 8511-8518

A straightforward strategy is proposed for grafting hydroxyl, carboxylic acid and epoxide groups along poly (epsilon-caprolactone) chains. Statistical copolymerization of epsilon-caprolactone (epsilon-CL ... [more ▼]

A straightforward strategy is proposed for grafting hydroxyl, carboxylic acid and epoxide groups along poly (epsilon-caprolactone) chains. Statistical copolymerization of epsilon-caprolactone (epsilon-CL) with alpha-chloro-epsilon-caprolactone (alpha-Cl-epsilon-CL) has been initiated by 2,2-dibutyl-2-stanna-1,3-dioxepane (DSDOP), followed by the atom transfer radical addition (ATRA) of but-3-en-1-ol, vinylacetic acid and 1,2-epoxyhex-5-ene, respectively, onto the alpha-chloro units of a poly(alpha-Cl-epsilon-CL-co-epsilon-CL) copolymer. alpha-Cl-epsilon-CL is easily prepared by the Baeyer-Villiger oxidation of 2-chlorocyclohexanone. The influence of the experimental conditions, i.e. temperature, solvent, catalyst, on the grafting yield has been discussed. Because ATRA is tolerant of the investigated functional groups, no protection/deprotection reaction is required, which is a major advantage of the method. [less ▲]

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See detailStretching calorimetry studies of poly(epsilon-caprolactone)/organoclay nanocomposites
Karaman, Vitaly M; Privalko, Eleonora G; Valery, P Privalko et al

in Polymer (2005), 46(6), 1943-1948

Poly(epsilon-caprolactone)/montmorillonite nanocomposites, prepared by bulk ring-opening polymerization of epsilon-caprolactone in the presence of tin(II) 2-ethylhexanoate as a catalyst and hydroxy groups ... [more ▼]

Poly(epsilon-caprolactone)/montmorillonite nanocomposites, prepared by bulk ring-opening polymerization of epsilon-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 linear thermal expansivities of both the intercalated and exfoliated nanocomposites could be fitted to the predictions of Chow's model assuming the apparent aspect ratio of clay nanoparticles of the order of 10. In the range of anelastic deformations, the values of the internal energy increments DeltaU/m for the intercalated nanocomposite lay somewhat below those for the corresponding neat polymer, while the DeltaU/m vs. epsilon plots for the exfoliated nanocomposite and for the corresponding neat polymer were nearly identical both in shape and in absolute values over the entire range of strains, up to the breaking strains epsilon(b). These data suggested higher and lower probabilities of interfacial debonding in the range of anelastic deformations for intercalated and exfoliated samples, respectively. [less ▲]

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See detailSelf-association of double-hydrophilic copolymers of acrylic acid and poly(ethylene oxide) macromonomer
Khousakoun, Eric; Gohy, Jean-François; Jérôme, Robert ULg

in Polymer (2004), 45(25), 8303-8310

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 ... [more ▼]

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 the PEO branches were varied. Dynamic light scattering (DLS) was used to characterize the aggregates formed in water and to investigate their response to stimuli, such as pH, temperature and ionic strength. In parallel, the morphology of the aggregates was directly observed by transmission electron microscopy (TEM). Well-defined aggregates were formed in the 5<pH<8 range, with a morphology strongly depending on the copolymer composition. At pH<5, the copolymers were poorly soluble and no well-defined structure was observed, whereas free chains were formed at pH>8 as consequence of the complete ionization of the PAA block. [less ▲]

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See detailGrafting of alkoxyamine end-capped (co)polymers onto multi-walled carbon nanotubes
Lou, Xudong; Detrembleur, Christophe ULg; Sciannamea, Valérie et al

in Polymer (2004), 45(18), 6097-6102

Multi-walled carbon nanotubes (MWNTs) have been successfully modified by polystyrene, poly(epsilon-caprolactone), and their block copolymers by addition reaction of the alkoxyamine-terminated precursors ... [more ▼]

Multi-walled carbon nanotubes (MWNTs) have been successfully modified by polystyrene, poly(epsilon-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 at the surface of MWNTs depends on the polymer molecular weight. [less ▲]

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See detailMorphology of core-shell-corona aqueous micelles: II. Addition of core-forming homopolymer
Lei, Liangcai C; Gohy, Jean-François; Willet, Nicolas ULg et al

in Polymer (2004), 45(13), 4375-4381

The poly(styrene)-block-poly(2-vinylpyridine)-block-poly(ethylene oxide) triblock copolymer PS200-b-P2VP(140)-b-PEO590, where the subscripts refer to the number average degrees of polymerization, forms ... [more ▼]

The poly(styrene)-block-poly(2-vinylpyridine)-block-poly(ethylene oxide) triblock copolymer PS200-b-P2VP(140)-b-PEO590, where the subscripts refer to the number average degrees of polymerization, forms spherical micelles in water, that consist of a PS core, a pH-responsive P2VP shell and a PEO corona. This triblock has been added with homo-PS before micellization in order to increase the volume fraction of the core-forming block. The length of the added homo-PS has been varied with respect to the length of the PS core-forming block: much shorter, much longer and approximately the same. The structure of the micelles has been investigated by transmission electron microscopy, static and dynamic light scattering. Homo-PS phase separates whenever its length is larger than the one of the PS core-forming chains; otherwise this phenomenon occurs beyond a critical concentration that depends on molecular weight. The addition of homo-PS has no influence on the morphology of the micelles and on the characteristic size of both the PS core and the P2VP shell, although the hydrodynamic diameter of the micelles is decreased. Substitution of styrene for homopolystyrene results in transition from a spherical to a dominant rod-like morphology. (C) 2004 Published by Elsevier Ltd. [less ▲]

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See detailSilica reinforced triblock copolymer gels
Theunissen, E.; Overbergh, N.; Reynaers, H. et al

in Polymer (2004), 45(6), 1857-1865

The effect of silica and polymer coated silica particles as reinforcing agents on the structural and mechanical properties of polystyrene-poly(ethylene/butylene)-polystyrene (PS-PEB-PS) triblock gel has ... [more ▼]

The effect of silica and polymer coated silica particles as reinforcing agents on the structural and mechanical properties of polystyrene-poly(ethylene/butylene)-polystyrene (PS-PEB-PS) triblock gel has been investigated. Different types of chemically modified silica have been compared in order to evaluate the influence of the compatibility between gel and filler. Time-resolved SANS and small-angle X-ray scattering (SAXS) shows that the presence of silica particles affects the ordering of the polystyrene domains during gelsetting. The scattering pattern of silica-reinforced gels reveals strong scattering at very low q, but no structure and formfactor information. However, on heating above the viscoelastic to plastic transition, the 'typical' scattering pattern of the copolymer gel builds-up. All reinforced gels are strengthened by the addition of the reinforcing agent. The transitions from a viscoclastic rubber to a plastic fluid and from a plastic fluid to a viscoelastic liquid are shifted to more elevated temperatures when silica is added to the triblock copolymer gel. [less ▲]

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See detailPolymer/layered silicate nanocomposites by combined intercalative polymerization and melt intercalation: a masterbatch process
Lepoittevin, Bénédicte; Pantoustier, Nadège; Devalckenaere, Myriam et al

in Polymer (2003), 44(7), 2033-2040

Poly(ε-caprolactone) (PCL) and poly(vinyl chloride) (PVC) layered silicate nanocomposites were prepared by combination of intercalative polymerization and melt intercalation. In a first step, high clay ... [more ▼]

Poly(ε-caprolactone) (PCL) and poly(vinyl chloride) (PVC) layered silicate nanocomposites were prepared by combination of intercalative polymerization and melt intercalation. In a first step, high clay content PCL nanocomposites were prepared by in situ polymerization of -caprolactone intercalated between selected organo-modified silicate layers. The polymerization was catalyzed with dibutyltin dimethoxide in the presence of montmorillonites, the surface of which were previously exchanged with (functionalized) long alkyl chains ammonium cations. Then, these highly filled PCL nanocomposites were added as masterbatches in commercial PCL and PVC by melt blending. The intercalation of PCL chains within the silicate layers by in situ polymerization proved to be very efficient, leading to the formation of intercalated and/or exfoliated structures depending on the organo-clay. These masterbatches were readily dispersed into the molten PCL and PVC matrices yielding intercalated/exfoliated layered silicate nanocomposites which could not be obtained by melt blending the matrix directly with the same organo-modified clays. The formation of nanocomposites was assessed both by X-ray diffraction and transmission electronic microscopy. Interestingly, this so-called 'masterbatch' two-step process allowed for preparing PCL nanocomposites even with non-modified natural clay, i.e. sodium montmorillonite, which showed a material stiffness much higher than the corresponding microcomposites recovered by direct melt intercalation. The thermal stability of PCL nanocomposites as a function of clay content was investigated by thermogravimetry (TGA). [less ▲]

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See detailNew nanocomposite materials based on plasticized poly(L-lactide) and organo-modified montmorillonites: thermal and morphological study
Paul, Marie-Amélie; Degée, Philippe; Henrist, Catherine ULg et al

in Polymer (2003), 44(2), 443-450

Plasticized poly(L-lactide) (PLA) based nanocomposites were prepared by melt blending of the matrix with 20 wt% of poly(ethyleneglycol) 1000 (PEG 1000) and different amounts of montmorillonite, organo ... [more ▼]

Plasticized poly(L-lactide) (PLA) based nanocomposites were prepared by melt blending of the matrix with 20 wt% of poly(ethyleneglycol) 1000 (PEG 1000) and different amounts of montmorillonite, organo-modified or not. The intercalation of the polymer chains between the aluminosilicates layers and morphological structure of the filled PLAs were analysed by wide-angle X-ray scattering (WAXS). Thermogravimetric analyses (TGA) and differential scanning calorimetry (DSC) were performed to study the thermal behaviour of the prepared composites. At constant filler level, it appears that from all the clays studied, the montmorillonite organo-modified by bis-(2-hydroxyethyl)methyl (hydrogenated tallowalkyl) ammonium cations brings the greater effect in terms of thermal stability. Increasing the amount of clay allows to delay the onset of thermal degradation of the plasticized polymer matrix. It was also pointed out, by WAXS and DSC analyses, that it exists a real competition between PEG 1000 and PLA for the intercalation into the interlayer spacing of the clay. (C) 2002 Elsevier Science Ltd. All rights reserved. [less ▲]

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See detailCharacterization of hyperporous polyurethane-based gels by non-intrusive mercury porosimetry
Pirard, René ULg; Rigacci, Arnaud; Marechal, Jacqueline ULg et al

in Polymer (2003), 44(17), 4881-4887

Evaporative drying of polyurethane-based gels produces xerogels. Supercritical drying after replacement of interstitial liquid by supercritical CO2 produces aerogels. SEM micrographs show that both ... [more ▼]

Evaporative drying of polyurethane-based gels produces xerogels. Supercritical drying after replacement of interstitial liquid by supercritical CO2 produces aerogels. SEM micrographs show that both materials are made up of small size particles gathered up in filament-shaped, strongly cross-linked aggregates. Density measurements show that they both have a large pore volume. When submitted to mercury porosimetry, the behavior of these materials is similar to that of inorganic aerogels, as previously observed. Mercury does not penetrate the pore network, but the whole material is densified. The usual Washburn equation cannot be used to analyze the mercury porosimetry. A well-suited equation based on a buckling model of filament-shaped aggregates has been developed in order to determine the pore volume distribution of mineral dried gels. This equation is also valid for analyzing the texture of organic hyperporous materials like polyurethane dried nanoporous gel. (C) 2003 Elsevier Science Ltd. All rights reserved. [less ▲]

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See detailThe in situ formation of a new initiator system for the syndiotactic anionic polymerization of methyl methacrylate in toluene at 0°C
Zundel, Thomas; Teyssié, Philippe; Jérôme, Robert ULg

in Polymer (2002), 43(25), 7191-7193

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 °C ... [more ▼]

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 °C. Predominantly syndiotactic PMMA is formed. [less ▲]

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See detailSynthesis and compatibilization ability of hydrogenated polybutadiene-b-polyamide 6 diblock copolymer in low density polyethylene and polyamide 6 blends
Harrats, Charef; Fayt, R.; Jérôme, Robert ULg

in Polymer (2002), 43(19), 5347-5354

This paper describes the synthesis of hydrogenated polybutadiene-b-polyamide 6 (HPB-b-PA6), a pure diblock copolymer, which consists of three main steps: synthesis of hydroxyl terminated polybutadiene ... [more ▼]

This paper describes the synthesis of hydrogenated polybutadiene-b-polyamide 6 (HPB-b-PA6), a pure diblock copolymer, which consists of three main steps: synthesis of hydroxyl terminated polybutadiene, its hydrogenation and functionalization with an epsilon-caprolactam blocked diisocyanate. In a third step the functionalized HPB is copolymerized with epsilon-caprolactam monomer via ring opening anionic polymerization. The compatibilization ability of the synthesized pure diblock copolymer was evaluated in low-density polyethylene (LDPE)/polyamide 6 (PA6) blends. The investigation includes phase morphology development using both optical and electron scanning microscopy. The ultimate tensile properties of the modified and non-modified blends were also evaluated. The synthesized pure diblock copolymer exhibits very interesting interfacial activity both in terms of particle size reduction and improvement of the interfacial adhesion between the incompatible LDPE/PA6 phases. The tensile properties of the investigated blends were also significantly affected by the addition of the copolymer. The efficiency of compatibilization was found to be very sensitive to the molecular characteristics such as composition and molecular weight of the copolymer. Among the copolymers investigated a copolymer containing 24 wt% PA6 and having a total molecular weight (M) over bar (a) of 87,000 was found to exhibit the most efficient interfacial activity. [less ▲]

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See detailPoly(epsilon-caprolactone)/clay nanocomposites prepared by melt intercalation: mechanical, thermal and rheological properties
Lepoittevin, Bénédicte; Devalckenaere, Myriam; Pantoustier, Nadège et al

in Polymer (2002), 43(14), 4017-4023

(Nano)composites of poly(epsilon-caprolactone) (PCL) were prepared by melt blending the polymer with natural Na+ montmorillonite and montmorillonite modified by hydrogenated tallowalkyl (HTA)-based ... [more ▼]

(Nano)composites of poly(epsilon-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 montmorillonites was used, as assessed by X-ray diffraction and transmission electron microscopy. Mechanical and thermal properties were studied as a function of the filter content by tensile testing, Izod impact testing, thermogravimetric analysis and differential scanning calorimetry. The rheological behaviour at 80 degreesC was also analysed in relation to the structure and content of the layered silicate. Effect of exfoliated silicates on the mechanical properties, thermal stability and flame resistance of PCL was considered. Stiffness and thermal stability improved with the filler loading until a content of 5 wt%. Further loading resulted in the levelling off and possibly in a decrease of these properties. A marked charring effect was observed upon exposure to a flame. [less ▲]

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See detailPolyethylene-layered silicate nanocomposites prepared by the polymerization-filling technique: synthesis and mechanical properties
Alexandre, Michaël ULg; Dubois, Philippe ULg; Sun, Tao et al

in Polymer (2002), 43(8), 2123-2132

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 ... [more ▼]

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 by trimethylaluminum-depleted methylaluminoxane before being contacted by a Ti-based constrained geometry catalyst. The nanocomposite was formed by addition and polymerization of ethylene. In the absence of a chain transfer agent, ultra high molecular weight polyethylene was produced. The tensile properties of these nanocomposites were poor and essentially independent of the nature and content of the silicate. Upon hydrogen addition, the molecular weight of the polyethylene was decreased with parallel improvement of the tensile and shear moduli, in relation to the filler content. The exfoliation of the layered silicates was confirmed by XRD analysis and TEM observation. The mechanical kneading of the molten nanocomposites resulted in the partial collapse of the exfoliated structure driven by the thermodynamic stability of the layered filler. [less ▲]

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See detailEffect of block copolymers of various molecular architecture on the phase morphology and tensile properties of LDPE rich (LDPE/PS) blends
Harrats, Charef; Fayt, R.; Jérôme, Robert ULg

in Polymer (2002), 43(3), 863-873

The emulsification efficiency of three different block copolymers consisting of hydrogenated polybutadiene (HPB) and polystyrene (PS), i.e. a pure diblock , a tapered diblock and a triblock copolymer has ... [more ▼]

The emulsification efficiency of three different block copolymers consisting of hydrogenated polybutadiene (HPB) and polystyrene (PS), i.e. a pure diblock , a tapered diblock and a triblock copolymer has been compared in low density polyethylene/polystyrene (LDPE/PS) blends rich in polyethylene. The comparison relies upon the ability of these potential interfacial agents to stabilize fine phase dispersion and to promote good interfacial adhesion. Based on the phase morphology, the ultimate tensile properties and the dynamic viscosity of the modified blends, the tapered diblock copolymer is clearly the most efficient emulsifier. For instance a plateau is observed in the property-copolymer content dependence when 2 wt% tapered diblock are used compared to ca. 5 wt% in case of the pure diblock. In contrast, no plateau is observed when the triblock copolymer is used. This is assumed to result from a less quantitative localization of these two copolymers i.e. the pue diblock or the triblock at the LDPE/PS interface. [less ▲]

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See detailSelf-aggregation of poly(methyl methacrylate)-block-poly(sulfonated glycidyl methacrylate) copolymers
Gohy, Jean-François; Antoun, Sayed; Jérôme, Robert ULg

in Polymer (2001), 42(21), 8637-8645

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 ... [more ▼]

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 SEC. These larger structures dissociate into smaller ones upon increasing the temperature. The extent of this dissociation process is strongly dependent on the copolymer composition. It is large as the content of the hydrophilic block is high. [less ▲]

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See detailMetallocene catalyzed polymerization of ethylene in the presence of graphite. 2. Structure and electrical properties of the composites
Pluta, Miroslaw; Alexandre, Michaël ULg; Blacher, Silvia ULg et al

in Polymer (2001), 42(22), 9293-9300

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 ... [more ▼]

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 and graphite. The extent of the filler dispersion depends on the method used for the composite preparation. Moreover, the graphite particles can be oriented by the molding of the samples used for the measurement of the electrical properties. This orientation is as pronounced as the melt viscosity of polyethylene is low, this characteristic feature changing with the preparation method. These structural details have consequences on the electrophysical properties and the percolation threshold. Finally, the thermal dependence of the electrical resistivity has been studied. [less ▲]

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See detailMicellization of quaternized poly(2-(dimethylamino)ethyl methacrylate)-block-poly(methyl methacrylate) copolymers in water
Antoun, Sayed; Gohy, Jean-François; Jérôme, Robert ULg

in Polymer (2001), 42(8), 3641-3648

Micellization of a series of amphiphilic quaternized poly(2-(dimethylamino)ethyl methacrylate)-block-poly(methyl methacrylate) (PQDMAEMA-b-PMMA) copolymers has been studied in water. The alkyl halide used ... [more ▼]

Micellization of a series of amphiphilic quaternized poly(2-(dimethylamino)ethyl methacrylate)-block-poly(methyl methacrylate) (PQDMAEMA-b-PMMA) copolymers has been studied in water. The alkyl halide used for the quaternization of the aminated block has an effect on the solution properties of the diblocks, that have been investigated by dynamic light scattering and surface tension measurements. When a short length alkyl halide is used, the diblock copolymers behave like traditional amphiphiles, whereas their behavior is similar to polysoaps in case of long alkyl halides. The size of the micelles increases when 1-bromopropan-3-ol is substituted for 1-bromopropane in the quaternization reaction. It is, however, independent of the structure of butyl bromide, i.e. n-butyl vs tert-butyl bromide. The solution properties of a star-shaped PQDMAEMA-b-PMMA copolymer have also been studied and compared to the linear counterpart. The star-shaped architecture actually prevents the block copolymer to be properly oriented at the air/water interface in agreement with the formation of unimer micelles. [less ▲]

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See detailMorphology and mechanical properties of poly(methylmethacrylate)-b-poly(alkylacrylate)-b-poly(methylmethacrylate)
Tong, J. D.; Leclère, Philippe; Doneux, C. et al

in Polymer (2001), 42(8), 3503-3514

A series of well-defined poly(methylmethacrylate) (PMMA)-b-poly(alkylacrylate)-b-PMMA triblock copolymers (MAM) has been synthesized by transalcoholysis of PMMA-b-poly(tert-butylacrylate)-b-PMMA ... [more ▼]

A series of well-defined poly(methylmethacrylate) (PMMA)-b-poly(alkylacrylate)-b-PMMA triblock copolymers (MAM) has been synthesized by transalcoholysis of PMMA-b-poly(tert-butylacrylate)-b-PMMA precursors by alkyl alcohols. The molecular weight (MW) of the outer PMMA blocks is in the 10,000-50,000 range, compared to 50,000-200,000 for the inner poly(alkylacrylate) block. Phase separation, as studied in direct space by atomic force microscopy, is observed for all the investigated triblock copolymers, except for the PMMA-b-poly(ethylacrylate)-b-PMMA and the PMMA-b-poly(n-propylacrylate)-b-PMMA triblocks of 10,000-50,000-10,000 MW. The ultimate tensile strength measured for the MAM triblocks is strongly dependent on the MW between chain entanglements for the central block. The tensile behavior is however affected by the partial miscibility of the outer and inner blocks when the PMMA MW is low. When this situation prevails, it makes the melt processing possible at temperatures lower than 200°C. [less ▲]

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See detailParticle-in-particle morphology for the dispersed phase formed in reactive compatibilization of SAN/EPDM blends
Pagnoulle, Christophe; Jérôme, Robert ULg

in Polymer (2001), 42(5), 1893-1906

Poly(ethylene-co-propylene-co-diene) (EPDM) containing 50 wt% of poly(ethylene-co-propylene) grafted with maleic anhydride (EP-g-MA) has been melt blended with poly(styrene-co-acrylonitrile) (SAN) added ... [more ▼]

Poly(ethylene-co-propylene-co-diene) (EPDM) containing 50 wt% of poly(ethylene-co-propylene) grafted with maleic anhydride (EP-g-MA) has been melt blended with poly(styrene-co-acrylonitrile) (SAN) added with various amounts of reactive SAN, i.e. SAN bearing either primary amine (SAN-NH2) or carbamate groups (SAN-carb). Carbamate groups are precursors of primary amines by thermal thermolysis during melt processing. These reactive systems are good models for studying the effect of the kinetics of the interfacial reaction on the phase morphology. Reaction of maleic anhydride with the primary amine is indeed very fast, at high temperature, in contrast to the reaction with carbamate, which is controlled by the carbamate thermolyis into primary amine. Special attention has been paid to the experimental conditions required for the development of the particle-in-particle morphology for the dispersed phase. Depending on the mixing sequence and the grafting kinetics (NH2/MA versus carb/MA), this particular phase morphology can be forced or occurs spontaneously. [less ▲]

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See detailPremade versus in situ formed compatibilizer at the PS/PMMA interface: contribution of the Raman confocal microscopy to the fracture analysis
Koulic, Christian; Yin, Zhihui; Pagnoulle, Christophe et al

in Polymer (2001), 42(7), 2947-2957

The interface of a two-layer assembly of polystyrene (PS) and poly(methyl methacrylate) (PMMA) was modified by an intermediate layer of either a premade poly(styrene-g-methyl methacrylate) copolymer (P(S ... [more ▼]

The interface of a two-layer assembly of polystyrene (PS) and poly(methyl methacrylate) (PMMA) was modified by an intermediate layer of either a premade poly(styrene-g-methyl methacrylate) copolymer (P(S-g-MMA)) or a preblend of mutually reactive PS and PMMA synthesized by atom transfer radical polymerization (ATRP). No significant difference was found in the interfacial fracture toughness measured by the double cantilever beam test, although the morphology of the interfacial region was not the same when observed by transmission electron microscopy. The premade copolymer formed a distinct interphase, in contrast to the sharp interface that was observed in the case of the reactive system. The analysis of the fracture surfaces by Raman confocal microscopy showed that the fracture occurred alternatively in the PS phase and either at the PS/copolymer interface for the non reactive system or at the PS/PMMA interface for the reactive one. [less ▲]

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