Jean-Claude Soutif

Characterization of CO2 plasma-treated polyethylene surface bearing carboxylic groups

Abstract The surface modification of high density polyethylene by a CO2 microwave plasma is described with the aim of fixing carboxylic groups. The characterization is discussed in terms of functionalization, degradation, crystallization and cross-linking. The formation of carboxylic acids seems mainly favored by the presence of the CO2 active species. The degradation leading via chain scissions to the formation of volatile byproducts is shown to be heterogeneous by mainly affecting amorphous zones. The structural modification is associated with a twisting motion of macromolecular chains having defects to more organized conformations. Finally, cross-linking appears weak due to the absence of chromophoric sites and of VUV radiations in the plasma.

Synthesis of thermoresponsive oxazolone end-functional polymers for reactions with amines using thiol-Michael addition “click” chemistry

Well-defined poly(N-isopropylacrylamide) (PNIPAM) polymers with an oxazolone ring at the chain end have been synthesized by combining controlled radical polymerization and thiol-Michael addition “click” chemistry. First, PNIPAM was synthesized using reversible addition–fragmentation chain transfer (RAFT) polymerization to afford polymers of controlled molecular weight and molecular weight distribution (Mn (1H NMR) = 3200 g mol−1; PDISEC = 1.05). The chain end was quantitatively converted to a thiol by aminolysis. Then, the functional monomer vinyl azlactone (VDM) was quantitatively “clicked” onto the chain end using a thiol-Michael addition reaction. The polymers were reacted with a model amine in order to demonstrate the potential of these polymers for bioconjugation.

Synthesis of poly(amide-ester)s from 2,6-pyridine dicarboxylic acid and ethanolamine derivatives – investigation of the polymer sorption behaviour towards heavy metal ions

Abstract The synthesis of poly(amide-ester)s from 2,6-pyridine dicarboxylic acid with ethanolamine derivatives has been investigated via two different ways. The first one is direct polycondensation with aminoalcohol leading to a statistical structure. The second one is polycondensation with an intermediate reactive compound, a bis(amide-alcohol), which has only one type of functional group leading to a more regular and defined polymer chain. These new polymers have in the main chain pyridine, ester and amide groups, known to have complexing abilities. Chelation attempts with various metals were done in order to evaluate their possible use as chelating resins. As the synthesized poly(amide-ester)s are insoluble in water, solid/liquid extractions have been carried out and the resins’ sorption for mixture of basic and/or precious metals have been studied under various experimental conditions (reaction time and hydrochloric acid concentration). The polycondensates are Au(III)-selective and their capacity and desorption characteristics have been evaluated.

Synthesis of chelating molecules as agents for magnetic resonance imaging, 31. Polycondensation of diethylenetriaminepentaacetic acid bisanhydride with diols and diamines

Abstract The polycondensation of diethylenetriaminepentaacetic acid (DTPA) bisanhydride with diols and diamines was investigated in order to obtain new complexing agents bearing aminoacetic groups along the polymer chain whose complexing properties should be better than their monomolecular homologues: EDTA (ethylenediaminetetraacetic acid), DTPA … Synthesis conditions have been studied to get linear water-soluble polymers destined to gadolinium complexation. Use of several types of comonomers has allowed us to obtain polycondensates having a varied density of COOH functions which will permit us to study its influence on their complexing properties towards different metallic cations.

Reactivity of surface groups attached on a plasma treated poly(propylene) film. Application to a new concept of a chelating membrane

The goal of the present work is the synthesis of a new chelating membrane from a trivial material, such as poly(propylene), through the fixation of the chelating groups after a cold plasma irradation. The cold plasma treatment compared to the electron beam irradiation is less degrading since only a few layers are affected. It leads to a surface bearing two types of reactive species: radicals able to initiate a post-grafting reaction of any kind of vinyl monomer and new surface functional groups - depending on the chemical nature of the cold plasma - able to react with a chelating molecule. So the modulation of the plasma conditions and the choice of the attached chelating groups onto the material can control the chelating capacity of such irradiated material. The nitrogen plasma modification of poly(propylene) (PP) leads to weakly cross-linked and slightly degraded surface bearing alkyl radicals and amino groups in various densities depending on plasma conditions. After the plasma irradiation, N-acryloyglycine (NAG) and diethylenetriamine-pentaacetic acid (DTPA) possessing specific chelating properties are grafted successfully onto the PP surface in different ways. All the grafted films present an important selectivity towards silver ions and consequently towards soft metallic ions, too. The ion capacity of NAG grafted films remains higher than with DTPA whatever the density of amino groups attached on the surface is.

Chemical modification of polymers. III, Kinetic aspects

Abstract In the chemical modification of polymers, the kinetic parameters are influenced not only by the reaction conditions (solvent, temperature, reagents concentrations, time) but also by the reactivity of the repeating units which in turn is influenced by the accessibility of the reagent to the site in question, the steric constraint being amplified by the molecular weight of the reagents and the degree of chain entanglement, conformation and tacticity of the polymer. The reactivity of the site may also be affected by the nature of the neighbouring units (already modified or unmodified). However, the first possible factors to be considered when an abnormal reaction rate is observed are liklihood of secondary reactions and the existence of isomeric units of different reactivity.

Chemical modification of polymers I. Applications and synthetic strategies

Abstract This paper does not claim to be an exhaustive review of chemical modification but rather aims to illustrate with some examples the vast possibilities offered by this method of synthesis. Grafting and crosslinking reactions as such, which lie outside the present concept of chemical modification (defined as the application of macromolecules in the traditional reactions of organic chemistry) as well as reactions in heterogeneous media do not form part of this review. Five aspects of main interest are: • —synthesis of copolymers not accessible by classical means, • —comparison of polymer modification and polymerization of functional monomers, • —aids to the analysis of polymer microstructures, • —introduction of reactive sites along a polymer chain, • —fixation of active molecules. Chemical modification of polymers is generally undertaken to synthesize polymers for well defined applications as can be seen in the case of supported catalysts and reagents, phase transfer catalysts, supported syntheses, and pharmacological use. The synthetic strategies will be described in more detail in Part II (fixation of acids on a polymeric chain). Part III will emphasize the kinetic aspects of the chemical modification of polymers and Part IV will deal with complex reactions.

Synthesis and complexing properties of resins containing aminocarboxylic acid as functional groups from diethylenetriaminepentaacetic acid bisanhydride and polyvinyl alcohols

The one-step reaction of diethylenetriaminepentaacetic acid bisanhydride with polyvinyl alcohols of different molecular weights produces chelating resins containing aminocarboxylic acids as functional groups. Metal sorption in different hydrochloric acid concentrations media and desorption studies were carried out and the results compared according to the density of complexing groups. The resins show a great sorption affinity towards Au(III). The desorption of Au(III) from the resins carried out by applying perchloric acid or thiourea as eluting agents led to the assumption that gold is strongly complexed indicating a particular mechanism of metal sorption.

Synthesis of chelating molecules as agents for magnetic resonance imaging: 2. Synthesis and complexing properties of N-acryloyl diethyl iminodiacetate copolymers

Abstract The synthesis of a monomer with diethyl iminodiacetate groups was investigated in order to obtain complexing copolymers. Copolymers of N-acryloyl diethyl iminodiacetate with acrylamide and acrylic acid were synthetized by a radical mechanism using 2,2′-azobisisobutyronitrile (AIBN) as initiator in dioxane at 80°C. The compositions of the copolymers were established by 1 H nuclear magnetic resonance (NMR) spectroscopy. The reactivity ratios were determined by both Fineman-Ross and Kelen-Tudos methods. The chelating ability of the synthetized copolymers was investigated with 152 Eu.

Chemical modification of polymers. II. Attachment of carboxylic acid containing molecules to polymers

Abstract The attachment of a molecule bearing an acid function to a macromolecular chain can be afforded by various types of linkages. Many of these are easily accessible and some can be reversible links. The ester linkage is specially well developed with hydroxylated polymers or non-hydroxylated polymers (especially epoxidized polymers) used as supports. Special attention is paid to the glycidyl group (= 2,3-epoxypropyl) which has been introduced to various polymers, providing species with pendent expoxy arms. The catalysis, stereochemistry, secondary reactions, methods of evaluation of the epoxide content, spectroscopic characterization and the mechanism of the addition of acids to epoxides are reviewed.