The abiotic UV-degradation behavior of oxodegradable LDPE was investigated in the presence of thermoplastic pea starch (TPPS) in this study. Oxodegradable LDPE was first melt-blended with thermoplastic pea starch (TPPS) using an internal mixing chamber to enhance the abiotic oxidative degradation of oxodegradable LDPE. Because of their different affinity, maleated polyethylene was added as compatibilizer. Tensile properties, thermal properties, and morphology of resulting melt-blends were determined at different content in TPPS. High content in TPPS (40 wt %) could be readily added to oxodegradable LDPE without affecting the tensile properties of resulting melt-blends. UV-ageing studies on compatibilized TPPS/oxodegradable LDPE melt-blends were carried out by Attenuated Total Reflectance infrared spectroscopy (ATR-FTIR), Dynamic Thermomechanical Analyses (DMTA) and Differential Scanning Calorimetry (DSC) under abiotic conditions. These results suggested a synergistic effect on the UV-ageing of TPPS-based melt-blends provided by both components during the first stage of UV-irradiation. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci 122: 489-496, 2011

Two types of biodegradable poly(epsilon-caprolactone (CLo))-co-poly(epsilon caprolactam (CLa)) copolymers were prepared by catalyzed hydrolytic ring-opening polymerization For the first type of materials the respective cyclic comonomers were added simultaneously in the reaction medium leading to the formation of copolymers having a random distribution of co-units within the polyesteramide sequence as evidenced by (1)H and (13)C NMR For the second type of copolymers the cyclic comonomers were added sequentially in the reaction medium yielding diblock polyesteramides again evidenced by NMR The thermal and thermo-mechanical properties of the copolymers were investigated by DSC and DMA and correlated with the copolymer topology and composition The copolymers were char acterized by a storage modulus and alpha transition temperature intermediate to the modulus and T(g) of the corresponding homopolymers The chemical composition and molecular weight of the copolymers proved to have only a limited effect on the thermo-mechanical properties of the materials The hydrolytic degradation of random copolymers was studied in a phosphate buffer at 60 degrees C and discussed in terms of chemical composition and molecular weight of the copolymers (c) 2010 Elsevier Ltd All rights reserved

Block copolymers based on a polyesteramide sequence and a polyether block were synthesized in bulk at 250 degrees C by ring-opening copolymerization (ROP) of epsilon-caprolactone (CLo) and epsilon-caprolactam (CLa) as initiated by Jeffamine(R) M1000, i.e., omega-NH2 copoly[(ethylene oxide)-co-(propylene oxide)] copolymer [P(EO-co-PO)-NH2]. For an initial molar ratio of [CLa](0)/[CLo](0) = 1, the copolymerization allowed for the formation of a diblock copolymer with a statistical polyesteramide sequence, as evidenced by C-13 NMR. Investigation of the ROP mechanism highlighted that CLo was first polymerized, leading to the formation of a diblock copolymer P(EO-co-PO)-b-PCLo-OH, followed by CLa hydrolysis to aminocaproic acid that inserted into the ester bonds of PCLo via aminolysis and subsequent condensation reactions. The outcome is the selective formation of P(EO-co-PO)-b-P(CLa-co-CLo)-OH diblock copolymers where the composition and length of the polyesteramide sequence can be fine-tuned by the [CLa](0)/[CLo](0) and ([CLa](0) + [CLo](0))/[P(EO-co-PO)-NH2](0) initial molar ratios.

The preparation and the characterization of nanotubes-reinforced poly(dimethyl)siloxane nanocomposites is reported. Surprisingly the use of "self pure" multiwall carbon nanotubes, that is, without any surface functionalization or specific surface treatment, turns out to be the most efficient approach to impart new key-properties to the silicone matrix.

An experimental study was carried out to design polylactide (PLA)-clay nanocomposites for developing fibers. PLA and 1-1.0 wt % of a selected organomodified bentonite (Bentone (R) 104-B104) were melt mixed to examine the effect of processing conditions (temperature, shear, residence time) on the morphology of performed polymer nanocomposites (PNC). Because of a good compatibility with PLA matrix, the dispersion of B104 occurred under different conditions without difficulty, and a similar morphology was obtained. The results obtained showed that at low temperature of mixing, the shear stress exerted on polymer has a key role on the extent of intercalation and delamination. Upscale experiments were further performed using optimized conditions and 4 wt % B104 was added to PLA matrix by melt blending to produce PNC for spinning. Then, the recovered PNC were melt spun to produce multifilaments yarns, and it was demonstrated that surprisingly, it is not necessary to use a plasticizer to spin a blend with 4 wt % B104. The properties of the yarns have been studied in terms of clay dispersion as well as thermal, mechanical, and shrinkage properties. B104 could be added up to 4 wt % into PLA without detrimentally sacrificing the tensile strength of melt-spun filaments, especially at high draw ratio. Interestingly, the PNC-based multifilaments were knitted and the flammability studied using cone calorimeter at 35 kW/m(2). A strong decrease, up to 46%, of the heat release rate was measured. (C) 2008 Wiley Periodicals, Inc.

End-grained wood/polyurethane composites were obtained by a water-based one-pot process free of diisocyanates. Wood was impregnated with both PEG and CBC-functionalized PEG as a coupling agent. A thorough study of the CBC-mediated end-groups conversion of PEG was achieved. It came out that functionalization conditions strongly affected the polyurethane chain extension and its grafting onto the wood structure. Antiswelling efficiency measurements showed that the one-pot procedure allowed to reach comparable dimensional stabilization than the diisocyanate-based process previously described. Morphological analysis demonstrated that such an improvement was attributable to the formation of cell wall-bulked WPCs.

The activity, recyclability, and chemical stability as a catalyst of undecyltin trichloride grafted to crosslinked polystyrene, [P-H]((1-t))[P-(CH2)(11)-SnCl3](t), with [P-H] the monomeric unit of the nonfunctionalized polymer and t the organotin-functionalized monomer fraction, are assessed in the ring-opening polymerization (ROP) of epsilon-caprolactone. Quantitative conversion is obtained within 2 h under conditions in which conversion is by far incomplete for two other organotin grafts, [P-H]((1-t))[P-(CH2)(11)-SnBuCl2](t) and [P-H]((1-t)){[P-(CH2)11-SnBuCl](2)O}(t/2). Even after 15 min of reaction, conversions of at least 70% are achieved for the grafted tin trichloride. The catalytic reactions of the grafted undecyltin trichloride, more particularly its chemical integrity and recycling ability, are monitored, in situ, at the solid-liquid interface, using high-resolution magic angle spinning (HR-MAS) H-1 and Sn-119 NMR. Residual tin contents in the reaction products were assessed by inductively coupled plasma/atomic emission spectroscopy (ICP/AES). The polydispersity index of the synthesized poly (epsilon-caprolactone), investigated with size exclusion chromatography, is closer to unity than for grafted tin dichloride catalysts.

Well-defined adaptative and amphiphilic polymer conetworks based on hydrophilic poly(N,N-dimethylamino-2-ethyl methacrylate) (PDMAEMA) and hydrophobic poly(e-caprolactone) (PCL) have been prepared by combination of ATRP, ROP, and "Click chemistry." Telechelic alpha,omega-alkyne terminated PCL crosslinker was obtained by ring-opening polymerization (ROP) of CL in THF at 80 degrees C initiated by 1,4-butanediol and catalyzed by tin(II) bis 2-ethyl hexanoate (Sn(Oct)(2)), followed by the quantitative esterification of hydroxyl end-groups by activated 4-pentynoic acid. In parallel, an azido-containing PDMAEMA-based copolymer was obtained in a three-step strategy involving primarily the copolymerization of DMAEMA with newly synthesized 2(2-azidoethoxy)ethyl methacrylate (AEEMA) monomer. The latter was obtained by nucleophilic substitution of chloride atom from 2-(2-chloroethoxy)ethanol by an azide group followed by the esterification reaction of the hydroxyl group with methaerylic anhydride. The copolymerization was carried out in an equivolumic mixture of H2O and isopropanol at r.t. and initiated by a omega-bromoisobutyryl oligo PEO macroinitiator in the presence of various ligated copper(I)-based catalysts. In a last step, both polymer precursors were chemically linked by the Huisgen-1,3-dipolar cycloaddition in anhydrous THF at r.t. using CuBr complexed by 2,2 '-bipyridine ligand as catalyst. Final material was characterized by the means of DSC and SEM, both attesting of a homogeneous distribution of the PCL crosslinkers and a highly porous structure in this new amphiphilic model conetworks. (C) 2008 Wiley Periodicals, Inc.

The synthesis of amphiphilic and adaptative block copolymers has been envisioned following a commutative two-step strategy involving atom transfer radical polymerization (ATRP) and the Huisgen-1,3-dipolar cycloaddition techniques. The reliability of this strategy is based on the use of an azido-containing ATRP initiator, the 2-(2-azidoethoxy)ethylbromoisobutyrate (N3EiBBr), able to be “clicked” to an alkyne-terminated derivative and to promote the ATRP polymerization from the active site. In the context of this work, an alkyne-terminated poly(ε-caprolactone) produced by ring-opening polymerization (ROP) of CL was employed as hydrophobic “clickable” segment. The N3EiBBr initiator was obtained by nucleophilic substitution of the chloride atom from 2-(2-chloroethoxy)ethanol by an azide function and followed by the esterification of the hydroxy function by bromoisobutyryl bromide. This initiator was employed in polymerization of N,N-dimethylamino-2-ethyl methacrylate (DMAEMA) monomer by ATRP in THF at 60 °C using CuBr complexed by 1,1,4,7,10,10-hexamethyltriethylenetetramine (HMTETA) as catalytic complex. Low initiation efficiencies were obtained and they were ascribed to intramolecular cyclization during the polymerization as evidenced by ESI-MS and 2D NMR spectroscopy. The “Click” coupling reaction was performed in THF at r.t. and was found to be efficient when using CuBr complexed by 2,2′-bipyridine ligand. To circumvent the low initiation efficiency, the N3EiBBr could be “clicked” in a first step to PCL precursors before initiating the polymerization of DMAEMA monomer by ATRP. In this context, various catalytic complexes in different composition ratio were employed to optimize the “click” coupling step. Moreover, this strategy was found to be suitable to produce well-defined PCL-b-PDMAEMA block copolymers, characterized by narrow polydispersity indices. Since ATRP and the Huisgen-1,3-dipolar cycloaddition both require the use of a copper(I)-based catalyst, the two first strategies were merged in a “one-pot” process in order to obtain in one step a well-defined block copolymer characterized by a narrow polydispersity index and predictable composition and block lengths.

Amphiphilic poly(epsilon-caprolactone)-b-poly[(methacrylate-graft-poly(ethylene oxide))-co-6-O-methacryloyl-D-galactopyranose] (PCL-b-P(MAPEO-co-GaMa)) with various compositions and molecular weights were synthesized via a controlled four-step strategy. The first step involves the synthesis of functionalized poly(epsilon-caprolactone) macroinitiator by ring-opening polymerization (ROP) of epsilon-caprolactone (CL) as initiated by aluminum triisopropoxide (Al(O(i)Pr)(3)). After selective bromination of the hydroxyl end-group of the resulting alpha-isopropoxy, omega-hydroxy poly(epsilon-caprolactone) by using 2-bromoisobutyryl bromide, the controlled radical copolymerization of alpha-methoxy, omega-methacrylate poly(ethylene oxide) (MAPEO) with 6-O-methacryloyl-1,2;3,4-di-O-isopropylidene-D-galactopyranose (DIGaMa) was performed by atom transfer radical polymerization (ATRP) in THF at 60 degrees C using CuBr ligated with 1,1,4,7,10,10 hexamethyltriethylenetetramine (HMTETA) as catalytic complex. In the final step, isopropylidene protective functions were selectively removed using an aqueous formic acid solution leading to the expected amphiphilic graft copolymers. The molecular characterization of those copolymers was performed by (1)H NMR spectroscopy and gel permeation chromatography (GPC) analysis. The self-assembly of the copolymers into micellar aggregates as well as the related critical micellization concentration (CMC) in aqueous media were determined by dynamic light scattering (DLS) and fluorescence spectroscopy, respectively. In parallel, the morphology of the solid deposits of micellar aggregates was examined with atomic force microscopy (AFM). (C) 2008 Wiley Periodicals, Inc.

The hydrolytic polymerization of ε-caprolactam (CLa) was carried out in bulk (in absence of solvent) at 250°C in the presence of carboxylic esters and aqueous H3PO2. It turned out that by conducting the ring opening polymerization (ROP) of CLa in the presence of PEO–C(O)–O–C5H11, a selected model ester (PEO=poly(ethylene oxide)), a remarkable activating effect of the ester function on the hydrolytic polymerization of the lactam was observed yielding PEO–b–PCLa diblock copolymers. The comparison of the CLa monomer conversions obtained with or without the model ester activated by H3PO2, as determined by 1H NMR spectroscopy, has enabled to propose a multi-step mechanism in which three major reactions occurred: (i) ester and lactam hydrolysis, (ii) aminolysis of the carboxylic ester by the resulting primary amine of the hydrolyzed/opened lactam ring and (iii) condensation reactions between carboxylic acids and both amine/hydroxyl functions. The overall result of this multi-step mechanism can be assimilated as an “insertion” of the opened lactam into the ester function. By conducting the hydrolytic polymerization of CLa in the presence of an aliphatic polyester chain, such as poly(ε-caprolactone) (PCLo), polyesteramides were recovered with high yields and random distributions of the CLa and CLo repetitive units as determined by 13C NMR.

Adaptive and amphiphilic poly(N,N-dimethylamino-2-ethyl methacrylate-graft-poly[epsilon-caprolactone]) co-networks (netP(DMAEMA-g-PCL)) were synthesized from a combination of controlled polymerization techniques. Firstly, PCL cross-linkers were produced by ring-opening polymerization (ROP) of epsilon-CL initiated by 1,4-butane-diol and catalyzed by tin(II) 2-ethylhexanoate ([Sn(Oct)2]), followed by the quantitative esterification reaction of terminal hydroxyl end-groups with methacrylic anhydride. Then, PCL cross-linkers were copolymerized to DMAEMA monomers by atom-transfer radical polymerization (ATRP) in THF at 60 degrees C using CuBr complexed by 1,1,4,7,10,10-hexamethyltriethylenetetramine (HMTETA) and 2-ethyl isobutyrylbromide (EiBBr) as catalytic complex and initiator, respectively. A comprehensive study of gel formation was carried out by employing dynamic light scattering (DLS) to determine the gel point as a function of several parameters and to characterize the viscous solutions obtained before the gel point was reached. The evolution of the mean diameters was compared to a model previously developed by Fukuda and these attest to the living formation of the polymer co-network. Furthermore, we also demonstrated the reliability of ATRP for producing well-defined and homogeneous polymer co-networks by the smaller deviation from Flory's theory in terms of cross-linking density. For sake of clarity, the impact of polymerization techniques over the final structure and, therefore, properties was highlighted by comparing two samples of similar composition, but that were produced by either ATRP or thermal-initiated free-radical polymerization (FRP).

This article reports on the preparation and partial characterisation of silicone-based coatings filled with low levels of either synthetic multiwall carbon nanotubes (MWCNTs) or natural sepiolite (NS). The antifouling and fouling-release properties of these coatings were explored through laboratory assays involving representative soft-fouling (Ulva) and hard-fouling (Balanus) organisms. The bulk mechanical properties of the coatings appeared unchanged by the addition of low amounts of filler, in contrast to the surface properties, which were modified on exposure to water. The release of Ulva sporelings (young plants) was improved by the addition of low amounts of both NS and MWCNTs. The most profound effect recorded was the significant reduction of adhesion strength of adult barnacles growing on a silicone elastomer containing a small amount (0.05%) of MWCNTs. All the data indicate that independent of the bulk properties, the surface properties affect settlement, and more particularly, the fouling-release behaviour, of the filled materials.