Ce travail de thèse porte sur la synthèse de (co)polymères thermosensibles présentant une fonctionnalité azlactone par polymérisation radicalaire contrôlée RAFT pour l’ancrage de biomolécules. Trois stratégies différentes ont été étudiées. La première stratégie a consisté en la synthèse d’un nouvel agent de transfert permettant d’obtenir des polymères thermosensibles à fonctionnalité azlactone en position . La seconde approche a permis d’introduire la fonctionnalité azlactone en position ω de copolymères thermosensibles via la combinaison de la polymérisation RAFT et de l’addition de Michaël « thiol-ène ». La dernière stratégie a conduit à des copolymères thermosensibles à fonctionnalité azlactone en position latérale par copolymérisation RAFT de la 2-vinyl-4,4-diméthylazlactone avec d’autres monomères. Enfin, la réactivité de ces copolymères thermosensibles pour l’ancrage d’une protéine modèle (lysozyme) a été mise en évidence. / The synthesis of well-defined azlactone-functionalized thermoresponsive copolymers was performed using the RAFT polymerization and their interaction with primary amines and proteins was studied. Three different strategies have been developed. The first strategy was based on the synthesis of a novel azlactone-functionalized chain transfer agent which was used to target well defined  azlactone-functionalized thermoresponsive polymers. In the second approach, ω-azlactone-terminated thermoresponsive copolymers were prepared by a combination of RAFT polymerization and “thiol ene” Michaël’s addition. In the last strategy, RAFT copolymerization of 2-vinyl-4,4 dimethylazlactone with other monomers has been performed to target well-defined azlactone functionalized copolymers. Finally, the reactivity of such reactive thermoresponsive copolymers was successfully demonstrated by bioconjugation with a model protein (lysozyme).

In 1980’s a new class of material named as dendrimer became popular both in the field of polymer science and engineering. Dendrimer is an example of symmetric, highly branched three dimensional globular nano-object. It possess several interesting physical and chemical properties like low solution and melt-viscosity, lower intermolecular chain entanglement, large number of end groups placed at the molecular periphery, relatively high solubility with respect to their linear counterpart. In order to get this perfectly branched structure, one has to go through the tedious multistep synthetic approach, repetitive chromatographic purification and protection-deprotection strategies in every step; all of which limits the large scale production and thus commercialization. On the other hand, hyperbranched polymer, a highly branched analogue of dendritic polymer with few defects in their branching architecture, which can be prepared in a single step, show similar physical and chemical properties as that of dendrimer. Polymerization of AB2 monomer is one of the well established method to generate hyperbranched polymer which upon polymerization, generates plenty of ‘B ’groups at the periphery along with a single ‘A’ group as a focal point in the resulting hyperbranched polymer as shown in Figure 1. From the structural point of view, hyperbranched polymers consist of three distinctly different compartments such as periphery, interior and a (single) focal point. During the past decade our lab have developed a novel melt trans-etherification process to generate polyethers and have utilized to access to a wide variety of hyperbranched structures. One of the challenges we addressed is to selectively functionalize the periphery of the hyperbranched polymer during the polymerization process. Polycondensation of ‘AB2’ monomer is not sufficient enough to generate a wide variety of hyperbranched polymer as the periphery of hyperbranched polymer is limited to the ‘B’ functional group unless it could be modified via ‘post-polymerization modifications’. Copolymerization of ‘AB2’ monomer with stoichiometric amount of ‘A-R’ monomer should result in hyperbranched polymer decorated with ‘R’ groups in the periphery that can be prepared in a single step. One of the prerequisite in the ‘AB2+A-R’ approach is that the comonomer ‘A-R’ should have silent ‘R’ group which does not interfere during the polymerization. During the copolymerization process with stoichiometric amount of ‘A-R’ monomer, ‘AB2’ monomer having one equivalent excess of ‘B’ can react with the ‘A’ group from ‘A-R’ monomer eventually generating the hyperbranched structure with peripheral ‘R’ groups. By appropriately choosing the ‘R’ group, one can access a wide class of hyperbranched polymer with the required functionality. Further by having a reactive ‘R’ group that is not participating in polymerization can act as a handle for post-polymerization modifications. For instance, copolymerization of 1-(6-Hydroxyhexyloxy)-3,5-bis(methoxymethyl)-2,4,6-trimethylbenzene (Hydroxy as ‘A’ and methoxy as ‘B’) and 6-bromo-1-hexanol where ‘OH’ and ‘-(CH2)6Br’ is ‘A’ and ‘R’ functional groups respectively, generates hyperbranched polymer with peripheral alkyl bromide functional groups as shown in Figure 2. The peripheral alkylbromides has been quantitatively transformed to quaternary ammonium or pyridinium salts using trimethyl amine or pyridine respectively. Thus by the post polymerization modification, we have transformed a hydrophobic hyperbranched polymer to a water soluble cationic hyperbranched polymer by simple and efficient post-polymerization modification. In a slightly different objective we Another problem that I have addressed is the difficulty associated with the aforementioned copolymerization approach. In spite of the fact that stoichiometric amounts of ‘A-R’ type monomer was taken in ‘AB2 + A-R’ approach, the extent of peripheral functionalization i.e. the incorporation of ‘R’ group is relatively lower. Further the molecular weight of the hyperbranched polymer obtained is also not high. One of the reasons we adopted ‘AB2 + A-R’ approach is to provide a functional handle for the subsequent post-polymerization modification. We modified the ‘AB2’ type monomer with a functionalizable handle to circumvent the lower amount of incorporation of the ‘A-R’ type monomer in ‘AB2 + A-R’ approach. Of all the readily functionalizable handles, click chemistry found to be a very useful tool for the post-polymerization modifications as the reactions conditions are mild, no side product, high selectivity, easy purification, etc. Another advantage of this reaction is that, we can incorporate any type of functional group starting from a single clickable parent hyperbranched polymer. In this particular project, I have Earlier design of the ‘AB2’ type monomer in our group, to prepare hyperbranched polymer via melt transetherification process, involved benzylic methoxy groups as ‘B’ in ‘AB2’ monomer leading to a hyperbranched polymer with peripheral methoxy groups. Transetherification under melt-conditions is an equilibrium reaction which was driven towards the hyperbranched polymer by continuous removal of methanol from the system as a volatile alcohol. In the new design of ‘AB2’ monomer; we have used benzylic allyloxy groups as ‘B’ in ‘AB2’ monomer, where in polymerization is driven by the continuous removal of allyl alcohol (instead of methanol as in the previous case), generates hyperbranched polymer with peripheral allyloxy group containing hyperbranched polymer. The allyloxy groups can be subsequently functionalized with a variety of thiol, we prepared a hydrocarbon-soluble octadecyl-derivative, amphiphilic systems using 2-mercaptoethanol and chiral amino acid (N-benzoyl cystine) hyperbranched structures by using thiol-ene click reactions (Figure 3). Polymers prepared from the parent hyperbranched polymer have significantly different physical properties like glass transition temperature (Tg), melting point (Tm) etc; thus considering the versatility of functionalization, parent polymer could be envisioned as a clickable hyperscaffold. More interestingly by functionalizing cystine derivative, we have demonstrated the possibility of biconjugation of the hyperbranched polymer. In summary, the limitations of ‘AB2+A-R’ copolymerization approach (low molecular weight Molecular weight and molecular weight distribution are very important parameters that influence the physical property and thus the application of the polymeric materials. As predicted by Flory, hyperbranched polymers are inherently polydisperse in nature and it tends to infinity when the percent of conversion is very high. Experimentally observed value of polydispersity is also significantly higher compared to their linear analogues. Control of the molecular weight and polydispersity of hyperbranched polymer by using a suitable amount of reactive multifunctional core has been demonstrated in this project. We have substantiated by using very little amount of ‘B3’ core along with ‘AB2’ monomer; wherein ‘B’ in ‘B3’ are more reactive than ‘B’ in ‘AB2’ monomer, regulate the molecular weight and polydispersity of the resulting hyperbranched polymer. As the ratio of core to monomer increases the molecular weight and polydispersity reduces in nearly linear fashion. In a slightly different objective, the core and periphery are functionalized with two different fluorophore by using orthogonal click reactions and demonstrated the possibility of energy transfer from periphery to the core of the hyperbranched polymer. In this section of my thesis, the self-assembly behavior of a periodically grafted amphiphilic copolymer has been studied. Polymer was synthesized via melt transesterification approach where hexaethylene glycol monomethyl ether (HEG) containing diester monomers are reacted with alkylyne diol monomers with varying carbon spacer (C12 and Another interesting problem, I approached is to functionalize the interior part of the hyperbranched polymer. In the case of dendrimer, as it is a step-wise synthesis, internal functionalization could be accomplished with the order of monomer addition i.e. by putting the internal functional group containing monomer first followed by other monomer not having those functional groups, whereas it is a bit challenging task for hyperbranched polymers especially when dealing with polycondensation of AB2 monomers, as it is a single step polymerization process. For a hyperbranched polymer in the polycondensation of ‘AB2’ monomer, the internal functional group should reside in between of the ‘A’ and ‘B’ functional group wherein the internal functional groups are silent during the process of polymerization. In order to do so, we have designed and synthesized a new AB2 monomer (a in Figure: 4). Here decanol is the volatile condensate that was removed during the transetherification reactions leading to a hyperbranched polymer having allyl group as the internal functional group and decyloxy as the peripheral functional group (b in Figure: 4). As a post-polymerization modification, the interior allyl groups were modified by thiol-ene click reaction with variety of thiol derivatives. In one example, the inherent hydrophobic nature of the parent hyperbranched polymer which is enhanced by the decyl chain at the molecular periphery, is converted to a alkaline water soluble hyperbranched polymer by the click reaction with mercapto succinic acid (d in Figure: 4) or mercapto propionic acid (c in Figure: 4) to the internal allyl groups, generating a novel amphiphilic hypersystem. This kind of amphiphilic systems are very interesting to study for their self-assembly behavior, in this particular case, the modified hyperbranched polymer adopts as a large spherical aggregates in alkaline water evidenced by FESEM (Figure: 4) and AFM images. Further investigation is being carried out to understand the exact nature of these aggregates. As the hyperbranched polymer contained ‘-S-‘ group in the interior, we utilized this as the scaffold for scavenging heavy metal ions like Hg2+ from aqueous solutions to the chloroform solution containing polymer. This hyperbranched polymer could trap Hg2+ ions even when present in ppm level of contamination.

L’objectif de ces travaux de thèse a été de développer des polyesters issus de ressources oléagineuses pour les utiliser comme additifs pour moduler la viscosité d’huiles lubrifiantes. Pour ce faire, l’approche par polycondensation de monomères de type hydroxy-acide a été privilégiée. Dans un premier temps, le poly(ricinoléate de méthyle) et son homologue saturé, le poly(12-hydroxystéarate de méthyle), ont été synthétisés dans une large gamme de masses molaires et leur utilisation comme épaississant d’huiles lubrifiantes a été démontrée. Dans un second temps, des polyesters dérivés du poly(ricinoléate de méthyle) et présentant des architectures de polymère en peigne ont été synthétisés par addition thiol-ène et polycondensation. Une étude de l’impact de l’architecture de ces polyesters sur leur comportement en solution a permis de prouver que les structures en peigne étaient les plus adaptées pour des applications visant, à la fois, un épaississement et une diminution du point d’écoulement de l’huile lubrifiante. Par la suite, des copoly(9-alkyl 12-hydroxystéarate)s en peigne possédant différentes chaînes pendantes ont été synthétisés afin de contrôler leur solubilité dans une huile minérale, la Yubase 4+, et ont permis de réduire la diminution de viscosité de cette huile avec la température. Finalement, l’étude dans le dodécane de deux copoly(9-alkyl 12-hydroxystéarate)s en peigne a révélé un phénomène d’agrégation des chaînes polymères lesquelles se désagrègent avec l’augmentation de la température, ce qui est en accord avec un des mécanismes d’action des additifs modulant la viscosité des huiles lubrifiantes décrit dans la littérature. / The aim of this thesis was to promote the use of polyesters from oleaginous resources as viscosity control additives for lubricants. The hydroxyl-acid type monomers were polymerized through polycondensation route. First, poly(methyl ricinoleate) and its homologous poly(methyl-12-hydroxystearate) were synthesized in a large range of molecular weights and their use as thickeners of lubricant oils was demonstrated. Secondly, comb polyesters derived from poly(methyl ricinoleate) were designed via thiol-ene addition and polycondensation process. The effect of the polyester architecture on their behavior in solution was investigated and revealed that comb polymers are the most suitable for applications that required a thickening efficiency and a pour point depressant effect. Then, comb (co)poly(9-alkyl 12-hydroxystearate)s with various pendant alkyl chains were designed in order to control their solubility in a mineral oil, the Yubase 4+, and to limit the oil viscosity decrease of these oils with temperature. Finally, the behavior in dodecane of two comb (co)poly(9-alkyl 12-hydroxystearate)s revealed that the polymer chains tend to aggregate at low temperature and to disaggregate with the temperature increase. This phenomenon is in accordance with one of the oil Viscosity Index Improver behaviors, described in literature.

L’objectif de cette thèse est de développer des matériaux polymérisés par rayonnement ultra-violet possédant une bonne balance des propriétés thermomécaniques entre résistance à la température, rigidité (strength) et résistance à l’impact. Une direction vers cet objectif est l’utilisation de résines (meth)acrylate modifiées avec des thiols polyfonctionnels. Cependant, les thiol-ene en général sont sujets à un problème de polymérisation prématurée incontrôlée même à l’abri de la lumière. Ce problème doit être traité puisque celui-ci conditionne le succès des thiol-ene dans le domaine des photopolymères. La première partie de cette thèse concerne l’élaboration de résine (meth)acrylate modifiée par l’incorporation d’un polythiol, le pentaerythritol tetrakismercaptopropionate (PETMP), à différents ratio. Les propriétés thermomécaniques et photochimiques de ces résines sont à l’étude. La seconde partie traite du problème de polymérisation prématurée incontrôlée des thiol-ene. Une étude de stabilité thermique aboutissant à des résultats très encourageant est proposée. Finalement, la dernière partie porte sur la caractérisation des réseaux photo-réticulés par pyrolyse-GC/MS. La compréhension de la constitution des réseaux tridimensionnels devraient apportés des avancées dans l’élaboration de nouveaux matériaux. Une nouvelle méthode de caractérisation utilisant la pyrolyse-GC/MS directe à multi-étapes est développée. Enfin, des résultats sur l’application de la méthode sur des matériaux à base de (meth)acrylate difonctionnel photopolymérisés ainsi qu’une tentative de caractérisation de matériaux à base de polythiol/(meth)acrylates photopolymérisés sont reportés puis discutés. / This thesis fall within an approach aiming to develop UV-processed materials having a good thermo-mechanical properties balance between strength, temperature resistance and impact resistance. A direction toward this objective is the use of photocurable (meth)acrylate resins modified with polyfunctional thiols. Indeed, thiol-ene chemistry is known to have poor sensitivity toward oxygen inhibition, to improve the dimensional stability and toughness properties of photocured materials. However, thiol-ene resins are subjected to premature uncontrolled dark polymerization, an issue that has to be solved for their success in the photopolymers area. The first part of this work is focused on the thermo-mechanical and the photopolymerization properties investigation of a pentaerythritol tetrakismercaptopropionate (PETMP) modified (meth)acrylate based resin by looking at different ratio of polythiol/(meth)acrylate. The second part is dedicated to the understanding of the thermal instability of such systems and to the solving of this issue. Finally, a special interest is brought to the characterization of photopolymeric networks by pyrolysis-GC/MS. The lake of deep understanding and view about how the cured networks are really constituted due to the difficulty to analyze insoluble cured polymers, prevents improvements in the formulation of high performance materials. Further information on cured networks constitution could bring useful information for the elaboration of new materials. A new characterization method based on direct multi-step pyrolysis-GC/MS is developed and an attempt on the characterization of polythiol (meth)acrylate material by Py-GC/MS is reported and discussed.

No description available.

Deux types de revêtements constitués d'environ 80% d'huile végétale ont été élaborés par chimie thiol-X sous UV. Le premier a été obtenu sous UV à partir d'huiles de lin native et standolisées en présence de 0,5 équivalent (SH/ène) de divers thiols, sous air, sans photoamorceur ni solvant. L'effet bénéfique de l'oxydation des acides gras sur la réaction d'addition thiol-ène et les propriétés finales des revêtements a été démontré. Ces matériaux présentent des propriétés équivalentes à celles des films obtenus par oxydation de l'huile de lin, faisant de ce procédé une alternative intéressante à la siccativation des huiles. Le deuxième type de revêtement a été obtenu sous UV à partir d'une huile de coton époxydée en présence de 0,25 équivalent (SHlépoxy) de 7- mercapto-4-méthyl coumarine et d'un photogénérateur de base permettant d'amorcer, sous air, la réaction d'addition thiol-époxy et l'homopolymérisation des fonctions époxy. Ces revêtements sont autoréparables sous UV. / Two types of coatings constituted about 80 wt% of vegetable oil were prepared by photoinitiated thiol-X chemistry. The first one has been prepared by crosslinking of native and stand linseed oil triglycerides in the presence of 0.5 equivalent of various thiols (SH/ene) under air and UV radiation, without photoinitiator or solvent. The oxidation of fatty acids has shown a beneficial effect on the thiol-ene addition as well as on the final properties of coatings. This process is thus an interesting alternative for the drying of oils. The second type of coating has been obtained by photocrosslinking triglycerides of epoxidized cottonseed oil in the presence of 0.25 equivalent (SH/epoxy) of 7-mercapto-4-methyl coumarine and a photobase generator under air. This latter initiated both thiol-epoxy addition and homopolymerization of epoxy functions. This coating could be auto-healable under UV exposure.

Plant derived oils bear intrinsic double-bond functionality that can be utilized directly for the thiol–ene reaction. Although terminal unsaturations are far more reactive than internal ones, studies on the reversible addition of thiyl radicals to 1,2-disubstituted alkenes show that this is an important reaction. To investigate the thiol–ene coupling reaction involving these enes, stoichiometric mixtures of a trifunctional propionate thiol with monounsaturated fatty acid methyl esters (methyl oleate or methyl elaidate) supplemented with 2.0 wt.% Irgacure 184 were subjected to 365-nm UV-irradiation and the chemical changes monitored. Continuous (RT– FTIR) and discontinuous (NMR and FT–Raman) techniques were used to follow the progress of the reaction and reveal details of the products formed. Experimental results supported by numerical kinetic simulations of the system confirm the reaction mechanism showing a very fast cis/trans-isomerization of the alkene monomers (<1.0 min) when compared to the total disappearance of double-bonds, indicating that the rate-limiting step controlling the overall reaction is the hydrogen transfer from the thiol involved in the formation of final product. The loss of total unsaturations equals thiol consumption throughout the entire reaction; although product formation is strongly favoured directly from the trans-ene. This indicates that initial cis/trans-isomer structures affect the kinetics. High thiol–ene conversions could be easily obtained at reasonable rates without major influence of side-reactions demonstrating the suitability of this reaction for network forming purposes from 1,2-disubstituted alkenes. To further illustrate the validity of this concept in the formation of cross-linked thiol–ene films a series of globalide/caprolactone based copolyesters differing in degree of unsaturations along the backbone were photopolymerized in the melt with the same trithiol giving amorphous elastomeric materials with different thermal and viscoelastic properties. High thiol–ene conversions (>80%) were easily attained for all cases at reasonable reaction rates, while maintaining the cure behaviour and independent of functionality. Parallel chain-growth ene homopolymerization was considered negligible when compared with the main coupling route. However, the comonomer feed ratio had impact on the thermoset properties with high ene-density copolymers giving networks with higher glass transition temperature values (Tg) and a narrower distribution of cross-links than films with lower ene composition. The thiol–ene systems evaluated in this study serve as model example for the sustainable use of naturally-occurring 1,2-disubstituted alkenes at making semi-synthetic polymeric materials in high conversions with a range of properties in an environment-friendly way. / Vegetabiliska oljor som innehåller dubbelbindningar kan användas direkt för thiolene reaktioner. Trots att terminala dubbelbindningar är mycket mer reaktiva än interna visar dessa studier att den reversibla additionen av thiyl radikaler till 1,2-disubstituerade alkener är en viktig reaktion. För att undersöka tiol–ene reaktionerna, som ivolverar dessa alkener förbereddes stökiometriska blandningar av en trifunktionell propionat tiol och enkelomättade fettsyrametylestrar (metyloleat eller metyl elaidat) samt 2.0 vikt.% Irgacure 184. Dessa blandningar utsattes för 365-nm UV strålning och de kemiska förändringarna studerades. De kemiska förändringarna analyserades med olika kemiska analysmetoder; realtid RT–FTIR, NMR och FT–Raman. Dessa användes för att analysera de kemiska reaktionerna i realtid och följa bildandet av produkterna. Reaktionsmekanismen bekräftades med hjälp av experimentella data och beräkningar av numeriska och kinetiska simuleringar för systemet. Resultaten visar en mycket snabb cis/trans-isomerisering av alkenmonomeren (<1.0 min) jämfört med den totala förbrukningen av dubbelbindningarna, vilket indikerar att det hastighetsbegränsande steget kontrolleras av väteförflyttningen från tiolen till slutprodukten. Förbrukningen av den totala omättade kolkedjan är lika med tiolförbrukningen under hela reaktionen, även om bildandet av produkten gynnas från trans-enen. Detta indikerar att den första cis/trans-isomerstrukturen påverkar kinetiken. Höga tiol-ene utbyten kan enkelt erhållas relativt snabbt utan inverkan av sidoreaktioner. Detta innebär att denna reaktion kan användas som nätverksbildande reaktion för flerfunktionella 1,2-disubstituted alkenmonomerer. Vidare användes fotopolymerisation i smälta på en serie globalid/kaprolaktonbaserade sampolyestrar med varierad grad av omättnad med samma tritiol vilket resulterade i bildandet av amorfa elastomeriska material med olika termiska och viskoelastiska egenskaper. Hög omsättning (>80%) uppnåddes relativt enkelt för samtliga blandningar oberoende av den initiala funktionaliteten. Homopolymerisation av alkenen var försumbar i jämförelse med den tiol–en-reaktionen. Mängden alkengrupper har inverkan på härdplastsegenskaperna där en hög andel alken ger en nätstruktur med högre glastransitionstemperatur (Tg). Tiol–ene reaktionen utvärderades i modellsystem baserade på naturlig förekommande 1,2-disubstituterade alkener för att demonstrera konceptet med tiol-förnätade halvsyntetiska material. / QC 20110915

L’objectif de cette thèse était d’allier, dans un même polymère, le contrôle de l’architecture macromoléculaire, la fonctionnalité et la possibilité de sa mise en oeuvre en phase fondue, tout en préservant l’aspect environnemental. Les structures polymères synthétisées sont basées sur des chaînes biodégradables et/ou biosourcées d’acide polylactic (PLA), de polyhydroxybutyrate (PHB) et de polycaprolactone (PCL). Ces dernières ont été assemblées dans des structures macromoléculaires branchées à design contrôlé et portant des fonctions thiols, ces fonctions ont permis le greffage de monomères dotés de groupements ammoniums quaternaires, sur les structures obtenues, via une addition radicalaire thiol-ène.Les produits obtenus ont été mélangés en phase fondue, par extrusion, avec des matrices de PLA et de PCL, pour préparer des films. Ces derniers ont fait l’objet d’une étude d’activité antibactérienne qui a montré une grande efficacité envers différents types de bactéries / The aim of this work was to develop polymers that combine controlled macromolecular architectures, functionality, melt processing and an environmentally friendly aspect. The obtained polymeric structures were based on biodegradable and/or biosourced chains of polylactic acid (PLA), polycaprolactone (PCL) and polyhydroxybutyrate (PHB). The lasts were assembled in branched macromolecular structures with controlled design and bearing thiol functions, these functions allowed the grafting of quaternary ammoniumcontaining monomers on the branched structures according to a thiol-ene radical addition mechanism. The final products were blended with neat matrices of PLA and PCL in the melt state, by extrusion process, to make polymeric films. The obtained film-shaped blends were subjected to antibacterial activity study showing there high efficiency against different types of bacteria

No description available.

No description available.