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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Copolymères diblocs amphiphiles et thermostimulables : synthèse contrôlée et étude préliminaire de leur auto-organisation / Amphiphilic and thermosensitive block copolymers : controlled synthesis and preliminary study of their self organization

Qayouh, Hicham 17 December 2013 (has links)
Les travaux présentés dans ce manuscrit ont porté sur l'élaboration de nouveaux copolymères dibloc amphiphiles (poly(ε-caprolactone)-b-poly(méthacrylate d'oligo(éthylène glycol) méthyl éther) biodégradables, thermostimulables et susceptibles d'être employés dans des applications respectueuses de l'environnement comme le traitement des eaux contaminées. La particularité de ces copolymères provient d'une part de la différence de solubilité des deux blocs et d'autre part de l'association d'un bloc hydrophobe biodégradable à un bloc thermostimulable hydrophile. Les propriétés de ces copolymères en milieu aqueux ont ainsi été évaluées en fonction de la température. Ces composés ont été obtenus par la combinaison de deux techniques de polymérisation contrôlée en utilisant un amorceur difonctionnel. Pour cela, deux stratégies ont été testées : i) la polymérisation par ouverture de cycle (POC) de l'ε-caprolactone à partir d'un macro-amorceur de poly(méthacrylate d'oligo(éthylène glycol) méthyl éther) à terminaison OH après avoir mis au point les conditions expérimentales de la POC en comparant plusieurs catalyseurs. ii) par polymérisation radicalaire par transfert d'atome (ATRP) du méthacrylate d'oligo(éthylène glycol) amorcée à partir d'une poly(ε-caprolactone) à extrémité bromée. Les températures critiques inférieures de solubilité (LCST) de ces copolymères ont été déterminées par UV visible. Leurs comportements micellaires ont été étudiés par mesures HPPS / The development of new biodegradable diblock copolymers poly(ε-caprolactone)-b-poly[oligo(ethylene glycol)methyl ether methacrylate], which could be used in environmental friendly applications such as treatment of contaminated water has been the main goal of this work. For the preparation these copolymers, the ring-opening polymerization (ROP) and the Atom Transfer Radical Polymerization (ATRP) were combined by using a bifunctional initiator. The two-step route for the synthesis of these copolymers was using either ATRP or ROP as first step and the other polymerization secondly. Each polymerization was studied carefully in order to control the macromolecular parameters of the copolymers. On the one hand, the ATRP of methacrylates bearing oligo(ethylene glycol) was carried out by using poly(ε-caprolactone) with bromide end-group as macroinitiator. On the other hand, the ring opening polymerization of ε-caprolactone was initiated by the hydroxyl end-group of the poly[oligo(ethylene glycol)methyl ether methacrylate], using tin octoate, tin tetrakis(phenylethynyl) or bismuth triflate as catalysts. The Low Critical Solution Temperature (LCST) of these amphiphilic diblock copolymers in aqueous medium have been determined by UV-visible spectroscopy. Their micellar behaviors were also studied by measuring size by HPPS
2

Unconventional radical miniemulsion polymerization

Qi, Genggeng 17 November 2008 (has links)
Conventional free-radical miniemulsion polymerization has been well studied since early 1970s. Conventional free-radical miniemulsion polymerizations have inherent limitations associated with uncontrolled free-radical polymerization mechanism. The goal of this work is to develop a variety of unconventional miniemulsion polymerization techniques by applying new polymerization techniques (typically in solution or bulk) to miniemulsion systems to overcome their inherent limitations and extend the application of free-radical miniemulsion polymerization. This work focused on the exploration of kinetic and mechanistic aspects of unconventional miniemulsion polymerizations. First, enzyme initiated free-radical miniemulsion polymerization, in contrast with those conventional chemical initiated miniemulsion polymerization, is demonstrated for the first time as an answer to the challenges associated with using the hydrophobic of vinyl monomers in aqueous enzymatic reactions. A procedure for enzyme initiated free-radical miniemulsion polymerization was formulated and stable poly(styrene) latexes were successfully synthesized. The kinetics of enzyme initiated free-radical miniemulsion polymerization and the effect of reaction conditions on the polymerization was elucidated. Second, RAFT miniemulsion polymerization of hydrophobic monomers was performed in CSTR trains and the transient states, previously identified by others in our group, were elucidated. Next, RAFT miniemulsion polymerization of a partially water soluble monomer was studied. RAFT miniemulsion polymerizations of gamma-methyl-alpha-methylene-gamma-butyrolactone, a partially water soluble lactone monomer derived from renewable sources, was successfully formulated. Homogeneous nucleation was found to play an important role in the free-radical "miniemulsion" homopolymerization of MeMBL. By using styrene as a comonomer, the RAFT miniemulsion polymerizations of MeMBL and styrene were well controlled and narrowly distributed copolymers of MeMBL/styrene were produced. Following the study of the partially water monomer, RAFT inverse miniemulsion polymerization was proposed for the polymerization of hydrophilic monomers. The kinetics of RAFT inverse miniemulsion polymerization of acrylamide exhibited the typical behavior of controlled polymerizations up to high conversions. The effects of reaction parameters on the polymerization rate and particle size were investigated. The dominant locus of radical generation for particle nucleation and the fate of desorbed monomeric radicals in inverse miniemulsion polymerizations were evaluated. Finally in this work, conclusions and implications are presented and ideas for future work are suggested.
3

Estudo experimental da polimerização via radical livre controlada em presença de radicais nitroxido (NMRP) / Experimental study of living free radical polymerization mediated nitroxide (NMRP)

Gonçalves, Maria Cecilia 13 September 2006 (has links)
Orientador: Liliane Maria Ferrareso Lona / Dissertação (mestrado) - Universidade Estadual de Campinas. Faculdade de Engenharia Quimica / Made available in DSpace on 2018-08-07T10:01:06Z (GMT). No. of bitstreams: 1 Goncalves_MariaCecilia_M.pdf: 1216282 bytes, checksum: 2482b360196051d5ed291cc3d7fa0ccc (MD5) Previous issue date: 2006 / Resumo: A polimerização via radical livre controlada mediante radicais nitróxido (NMRP) tem recebido cada vez mais atenção como uma técnica para produção de polímeros com estrutura altamente controlada. Distribuições de pesos moleculares estreitas são obtidas, com polidispersidades baixas. Neste trabalho, será estudado o processo NMRP, no qual ocorre a adição de um radical nitróxido estável, como o 2,2,6,6-tetrametil-l-piperidinoxil (TEMPO) para capturar o radical em crescimento. Embora o processo NMRP de ao polímero características controladas (polidipersidades baixas e pesos moleculares que aumentam linearmente com a conversão), ainda existe um desafio nos processos controlados, por apresentarem baixas velocidades de reação. O objetivo principal deste trabalho está focado num estudo experimental do processo NMRP visando aumentar a velocidade de reação sem perder as características principais do processo. O efeito de dois iniciadores BPO (peróxido de benzoíla) e TBEC (tert-butilperóxido-2-etilhexil carbonato) foi analisado. Observou-se que o TBEC (iniciador com constante de decomposição baixa) foi capaz de aumentar significativamente a taxa de polimerização do processo NMRP, quando comparado ao BPO, pois conversões mais altas foram obtidas, num mesmo tempo de reação, mantendo a característica controlada do sistema. O uso do TBEC apresenta uma vantagem frente ao BPO em processos controlados, não somente porque reduz o tempo de reação, mas também porque concentrações menores de iniciador e controlador foram usadas, obtendo uma taxa de reação ainda maior, o que reduz o custo operacional. Para as condições estudadas, comprovou-se experimentalmente que a taxa de reação é inversamente proporcional à concentração inicial de TEMPO, para uma mesma concentração de iniciador. A análise dos resultados através da aplicação da técnica de planejamento de experimento auxiliou numa melhor compreensão do sistema e na obtenção de condições ótimas de operação para se obter baixas polidispersidades e baixos tempos de polimerização / Abstract: NMRP process (Nitroxide Mediated Radical Polymerization) has received increasing attention as a technique for production polymers with highly controlled structures, narrow molecular weight distribution (MWD) and polydispersity index dose to 1.0. In this work 2,2,6,6-tetramethyl-l-piperidinoxyl (TEMPO) is used as the stable radical to reversibly terminate the growing polymer chain. Polymerizations were performed in ampoules, using TBEC (tert-butylperoxy-2-ethylhexyl carbonate) and BPO (benzoyl peroxide) as initiators. With the purpose of enhancing the reaction rate for NMRP process maintaining the controlled and living characteristics of the polymer synthesized (low polidispersity and molecular weights increasing linearly with conversion) an experimental study was done to evaluate the effect of two different initiators (BPO and TBEC). It was observed that TBEC (initiator with low decomposition rate) was able to enhance significant1y the polymerization rate compared to BPO, keeping the living and controlled characteristics of the system. The results show that TBEC seems to be a promising initiator that make the NMRP process more efficient, not only because it reduces the polymerization time, but also because it allows smaller amounts of controller and initiator to be used. For the operational conditions studied, experimental results with TBEC exposed that the polymerization rate in inversely proportional to the initial concentration of TEMPO, for the same amount of initiator. Using a statistical planning, it was possible to obtain a better understanding of the system and to search for operating conditions that bring low polydispersity and low reaction rates. Finally, the results are expected to have significant benefits for controlled polymerization on an industrial setting / Mestrado / Desenvolvimento de Processos Químicos / Mestre em Engenharia Química
4

Particules greffées d'homopolymères et de copolymères pour l'élaboration de nanocomposites modèles : dispersion des particules, dynamique des chaînes greffées en relation avec les propriétés rhéologiques / Grafted particles with homopolymers and copolymers for the development of model nanocomposites : particles dispersion, grafted chains dynamics and link with the rheological properties.

Genevaz, Nicolas 18 December 2014 (has links)
Les nanocomposites polymère intéressent depuis de nombreuses années la communauté scientifique, du fait, notamment, de leurs bonnes propriétés mécaniques. Il est établi que l'amélioration des propriétés mécaniques observées dans les nanocomposites est principalement due à des effets de structure (dispersion des particules) et à des effets d'interface (interactions particule/matrice et particule/particule). Cependant, de nombreux résultats expérimentaux restent difficiles à expliquer. Dans ce contexte, nous avons synthétisé des nanocomposites modèles constitués de nanoparticules de silice greffées de chaînes de polystyrène (PS) (ou de PS-b-poly(acrylate de tertio-butyle)) par polymérisation radicalaire contrôlée par les nitroxydes (NMP) et réparties dans une matrice de PS. Ces nanocomposites ont ensuite été caractérisés en couplant la diffusion de rayons X et la microscopie électronique à transmission. En variant la taille des chaînes de la matrice, nous sommes parvenus à obtenir différentes répartitions spatiales de particules allant de la dispersion totale à l'agrégation en passant par un état intermédiaire s'apparentant à un réseau connecté aux fractions volumiques élevées. Les propriétés mécaniques de ces nanocomposites ont été étudiées par des mesures de cisaillement aux faibles fréquences puis reliées aux différentes dispersions observées. Enfin, nous avons mesuré la dynamique locale et intermédiaire des chaînes de polymères greffées dans les matériaux préparés en couplant la diffusion quasiélastique des neutrons (rétrodiffusion et écho de spin) et la résonance magnétique nucléaire. Ces mesures ont ensuite été reliées aux propriétés mécaniques des nanocomposites. / Polymer nanocomposites interest for many years the scientific community, due in particular, to their good mechanical properties. It is established that the improvement of these properties observed in nanocomposites are mainly due to structural effects (particles dispersion) and interfacial effects (particle/matrix and particles/particles interactions). However, many experimental results are difficult to explain. In such a context, we have synthesized model nanocomposites based on silica nanoparticles grafted with polystyrene (PS) chains (or PS-b-poly(ter-butyl acrylate)) by nitroxide mediated polymerization and dispersed in a PS matrix. Then, these nanocomposites have been characterized by combining X-ray scattering and transmission electronic microscopy. By varying the length of the matrix chains, we have obtained different fillers structure going from individual nanoparticles dispersion to aggregate, up to an intermediate state (equivalent to an interconnected network for high volume fraction). Mechanical properties of these nanocomposites were studied by the mean of shear measurements at low frequency and linked to the different states of dispersion observed. Finally, we have measured local and intermediate dynamics of the grafted polymer chains by combining quasielastic neutron scattering (backscattering and spin echo) and nuclear magnetic resonance. Then, we have linked these measurements with the mechanical properties of the materials.
5

Polietilenoksido šonines grandines turinčių polielektrolitų sintezė gyvybingosios radikalinės polimerizacijos metodais / Synthesis of polyelectrolytes containing poly(ethylene oxide) side chains by living radical polymerization

Krivorotova, Tatjana 15 September 2010 (has links)
Vienas iš šiuolaikinės polimerų chemijos uždavinių – gauti numatytos molekulinės masės ir architektūros polimerines medžiagas. Neseniai buvo sukurti nauji radikalinės polimerizacijos metodai, kurie priskiriami gyvybingajai (valdomai) polimerizacijai (GRP). Makromonomerų (MM) gyvybingoji radikalinė polimerizacija yra efektyvus būdas gauti šepetinius (cilindrinius) polimerus). Šepetiniai polimerai – tai makromolekulės, kuriose prie pagrindinės polimerinės grandinės prijungta daug šoninių mažesnės molekulinės masės polimerinių (oligomerinių) grandinių. Dėl tarp šoninių grandinių esančių erdvinės stūmos jėgų tokios makromolekulės įgauna neįprastų savybių, pvz., standumą, cilindrinę formą, didelį segmentų tankį. Pagrindinis šio darbo tikslas buvo susintetinti norimos sudėties šepetinius polielektrolitinius polimerus, sudarytus iš krūvį turinčios poli(met)akrilato pagrindinės grandinės ir šoninių polietilenoksido grandinių, ir ištirti jų savybes. Svarbiausieji šio darbo rezultatai, atspindintys jo naujumą, originalumą ir svarbą: Pirmą kartą nuodugniai ištirta metakrilo rūgšties (MAR) ir dviejų skirtingų molekulinių masių polietilenoksido metakrilatų PEOnMEMA (n = 5, 45) kopolimerizacija įprastiniu radikaliniu ir RAFT metodais. Sukurta metodika PEO makromonomerų kopolimerizacijos kinetikai tirti, užrašant 1H BMR spektrus in situ ir įvertinant likutinę monomerų koncentraciją reakcijos mišinyje bei momentinę kopolimero sudėtį iki gilių konversijų. Netiesiniu kintamųjų paklaidų metodu... [toliau žr. visą tekstą] / The main goal of this work was to synthesize polyelectrolyte brushes containing poly(ethylene oxide) side chains by living polymerization. Brush-like macromolecules are unique polymer molecules whose conformation and physical properties are controlled by steric repulsion of densely grafted side chains. Molecules can be either flexible or stiff, depending on the grafting density and the length of the side chains. Polymerization of macromonomers is one of the most useful ways to prepare brush copolymers. However, with the macromonomer method, the distribution of the spacing of the side chains cannot be entirely controlled which along with broad and multimodal molecular weight distribution makes these polymers heterogeneous. These problems were considered to be overcome with the use of controlled/living polymerization. Conventional free-radical and RAFT copolymerization of poly(ethylene oxide) substituent containing methacrylate macromonomers, PEO5MEMA and PEO45MEMA, with methacrylic acid (MAA) was studied by the use of 1H NMR spectroscopy for an analysis of residual monomers. RAFT copolymerization of PEO45MEMA and MAA enabled to synthesize comb copolymers with low composition distribution and more homogeneous distribution of PEO side chains along the mainchain. Amphiphilic non-ionic blockcopolymers poly(lauryl methacrylate) (PLMA) – P(PEOnMEMA) and amphiphilic anionic blockcopolymers PLMA – PMAA were prepared by the RAFT method, and their properties in aqueous and THF... [to full text]
6

Synthesis of polyelectrolytes contaiting poly(ethylene oxide) side chains by living radical polymerization / Polietilenoksido šonines grandines turinčių polielektrolitų sintezė gyvybingosios radikalinės polimerizacijos metodais

Krivorotova, Tatjana 15 September 2010 (has links)
The main goal of this work was to synthesize polyelectrolyte brushes containing poly(ethylene oxide) side chains by living polymerization. Brush-like macromolecules are unique polymer molecules whose conformation and physical properties are controlled by steric repulsion of densely grafted side chains. Molecules can be either flexible or stiff, depending on the grafting density and the length of the side chains. Polymerization of macromonomers is one of the most useful ways to prepare brush copolymers. However, with the macromonomer method, the distribution of the spacing of the side chains cannot be entirely controlled which along with broad and multimodal molecular weight distribution makes these polymers heterogeneous. These problems were considered to be overcome with the use of controlled/living polymerization. Conventional free-radical and RAFT copolymerization of poly(ethylene oxide) substituent containing methacrylate macromonomers, PEO5MEMA and PEO45MEMA, with methacrylic acid (MAA) was studied by the use of 1H NMR spectroscopy for an analysis of residual monomers. RAFT copolymerization of PEO45MEMA and MAA enabled to synthesize comb copolymers with low composition distribution and more homogeneous distribution of PEO side chains along the mainchain. Amphiphilic non-ionic blockcopolymers poly(lauryl methacrylate) (PLMA) – P(PEOnMEMA) and amphiphilic anionic blockcopolymers PLMA – PMAA were prepared by the RAFT method, and their properties in aqueous and THF... [to full text] / Vienas iš šiuolaikinės polimerų chemijos uždavinių – gauti numatytos molekulinės masės ir architektūros polimerines medžiagas. Neseniai buvo sukurti nauji radikalinės polimerizacijos metodai, kurie priskiriami gyvybingajai (valdomai) polimerizacijai (GRP). Makromonomerų (MM) gyvybingoji radikalinė polimerizacija yra efektyvus būdas gauti šepetinius (cilindrinius) polimerus). Šepetiniai polimerai – tai makromolekulės, kuriose prie pagrindinės polimerinės grandinės prijungta daug šoninių mažesnės molekulinės masės polimerinių (oligomerinių) grandinių. Dėl tarp šoninių grandinių esančių erdvinės stūmos jėgų tokios makromolekulės įgauna neįprastų savybių, pvz., standumą, cilindrinę formą, didelį segmentų tankį. Pagrindinis šio darbo tikslas buvo susintetinti norimos sudėties šepetinius polielektrolitinius polimerus, sudarytus iš krūvį turinčios poli(met)akrilato pagrindinės grandinės ir šoninių polietilenoksido grandinių, ir ištirti jų savybes. Svarbiausieji šio darbo rezultatai, atspindintys jo naujumą, originalumą ir svarbą: Pirmą kartą nuodugniai ištirta metakrilo rūgšties (MAR) ir dviejų skirtingų molekulinių masių polietilenoksido metakrilatų PEOnMEMA (n = 5, 45) kopolimerizacija įprastiniu radikaliniu ir RAFT metodais. Sukurta metodika PEO makromonomerų kopolimerizacijos kinetikai tirti, užrašant 1H BMR spektrus in situ ir įvertinant likutinę monomerų koncentraciją reakcijos mišinyje bei momentinę kopolimero sudėtį iki gilių konversijų. Netiesiniu kintamųjų paklaidų metodu... [toliau žr. visą tekstą]
7

SILIPOLYSALEN : étude du greffage par polymérisation contrôlée de complexes de salen sur silicium pour une application en catalyse asymétrique hétérogène / SILIPOLYSALEN : grafting by controlled polymerization of salen complexes on silicon for heterogeneous asymmetric catalysis applications .

Zidelmal, Nacim 14 March 2018 (has links)
Les complexes métalliques chiraux de type salen sont connus pour la diversité de leur utilisation en catalyse conduisant à la préparation de nombreux synthons énantio-enrichis. Conformément au concept de chimie verte, l'un des principaux objectifs est d'établir une procédure efficace pour la récupération et la réutilisation de ces catalyseurs. Dans ce contexte, l'objectif de ce travail est de fonctionnaliser la surface du silicium par greffage covalent de ces catalyseurs par polymérisation contrôlée notamment la polymérisation radicalaire par transfert d’atome (ATRP) pour leur récupération et leur réutilisation. Ainsi, des copolymères de styrène contenant 5 à 50 mol% d’un comonomère salen dissymétrique ont été synthétisés par ATRP en solution. Le caractère contrôlé des polymérisations n’est obtenu que lorsque l’incorporation du comonomère salen est inférieure ou égale à 10 mol %.Après complexation au cobalt, les polymères correspondants se sont révélés capables de réaliser une activation coopérative efficace, conduisant au produit ciblé avec des rendements et des sélectivités élevés en tant que catalyseurs dans la réaction de dédoublement cinétique hydrolytique de l’épibromohydrine.Nous avons également réalisé la polymérisation du styrène sur la surface de silicium par ATRP après greffage de l’amorceur. Plusieurs méthodes de greffage de l’amorceur ont été utilisées soit d’une manière directe à partir de la surface hydrogénée, soit indirecte à partir d’une surface acide ou ester. Le styrène a été ensuite efficacement polymérisé en masse avec succès de façon contrôlée sur le silicium, avec des épaisseurs de couche comprise entre 9 et 29 nm déterminées par ellipsométrie et microscopie à force atomique / Chiral metal complexes of salen type are known for their efficient catalytic activity leading to the preparation of enantioselective enriched synthons. In accordance with the concept of green chemistry, one of the main challenge is to establish a procedure for the recovery and reuse of these catalysts. In this context, the objective of this work is to functionalize the silicon surface by grafting these catalysts by controlled polymerization especially by Atom Transfer Radical Polymerization (ATRP) to facilitate their recovery and reuse.Thus, styrene copolymers containing 5 to 50 mol % of an disymmetric salen comonomer were synthesized by ATRP in solution. The controlled nature of the polymerizations is obtained only when the incorporation of the salen comonomer is less than or equal to 10%.After complexation with cobalt, these complexes are shown to be capable of effective cooperative activation, leading to the targeted product with high yields and selectivities as catalysts in Hydrolytic Kinetic Resolution (HKR) of epibromohydrin.Constantio Constantini fratre imperatoris, matreque Galla.We also reported the polymerization of styrene on the silicon surface by ATRP after grafting of the initiator. Several methods of initiator grafting have been used either directly from the hydrogenated surface or indirectly from an acid or ester surface. Styrene has been successfully mass polymerized in a controlled manner on silicon with thicknesses of 9-29 nm of the layer obtained by ellipsometry and Atomic Force Microscopy.
8

Polymer and surface modifications for antibacterial purposes / Modifications de polymères et de surfaces à visées antibactériennes

Nguyen, Thi Phuong Thu 28 November 2019 (has links)
La contamination microbienne des surfaces est l’une des préoccupations majeures des secteurs d’activités comme l’industrie agro-alimentaire, la santé publique et les milieux hospitaliers. Face aux problèmes de santé publique liés à contamination bactérienne sur les surfaces, la préparation de surfaces aux propriétés antibactériennes est devenue un intérêt de recherche majeur pour de nombreux scientifiques et ce, dans de nombreux domaines de recherches. Du point de vue de la chimie, des matériaux et de la microbiologie, la fonctionnalisation des surfaces de matériaux polymères préexistants sans altérer leur propriété initiale est une solution séduisante. Pour cela, développer des nouveaux matériaux antibactériens/antifouling où la surface serait fonctionnalisée par des polymères antimicrobiens, greffés de manière robuste i.e. de façon covalente représente une solution idéale. Afin de faciliter et d’accélérer le processus de criblage, il est proposé dans ce travail une nouvelle approche pour obtenir des polymères ayant des propriétés antimicrobiennes à la fois en solution et à partir de la surface. Ce travail comprend une étude de (co)-polymérisations contrôlées d'esters actifs servant d’intermédiaires pouvant être post-modifiés pour synthétiser des polymères d'intérêts présentant les caractéristiques antimicrobiennes attendues.Ce travail démontre que la polymérisation radicalaire contrôlée en présence de Cu(0)/Cu(II) est une technique appropriée qui permet de préparer facilement des (co)-polymères réactifs, en solution mais aussi à partir de surface de poly (téréphtalate d’éthylène), communément appelé PET. Dans un premier temps, nous aborderons l'étude de la polymérisation contrôlée du méthacrylate de pentafluorophényle (PFPMA), avec son optimisation en solution, puis à partir de surface du PET porteuse de groupement d’amorçage. De plus, la polymérisation du méthacrylate de p-nitrophényle (NPMA) sera également examinée, ainsi que la copolymérisation des deux esters actifs là-encore par polymérisation de type contrôlée en présence de Cu(0)/Cu(II). La post-modification des polymères activés est ensuite présentée. La post-modification s’est révélée efficace et facile à mettre en œuvre. La structure et les caractéristiques des polymères obtenus ont été analysées et confirmées. Il est à noter que la post-modification a pu être effectuée par un processus séquentiel avec une fonctionnalisation simple ou avec plusieurs huiles essentielles, qui possèdent des propriétés naturelles antibactériennes ou antioxydantes. Différents films de PET ont été modifiés, des polymères aux propriétés anti-adhérentes ont été greffés par cette même méthodologie. Ces surfaces modifiées ont été testées contre deux bactéries modèles telles que Staphylococcus aureus et Pseudomonas aeruginosa afin de déterminer si les modifications de surface ont conféré au film de PET les propriétés biologiques attendues. / Microbial contamination on surfaces has become major concern in various areas including industrial process as well as public health and hospitalization. Being aware of several problems causing by adherence and attachment of bacteria on a surface, preparation of antibacterial surface has become a global research interest for researchers in many domains. From the chemistry integrated with material science and microbiology point of view, functionalization of existing polymeric material surfaces is an attractive solution. In this domain, the surface functionalized with covalently grafted antimicrobial polymers represents an ideal solution. In order to facilitate the screening process, it is proposed in this particular research a new approach to obtain polymers with antimicrobial properties both in solution and from surface. The present approach includes a study in controlled (co)polymerization of active ester(s) serving as intermediate templates that can be eventually modified by polymer post-modification process to fabricate polymer of interest with expected antimicrobial characteristics.In general, it is demonstrated herein that the use of Cu(0)-mediated reversible deactivation radical polymerization (RDRP) is a suitable technique that allows facile preparation of reactive (co)polymers in solution and from surface of poly(ethylene terephthalate). First of all, this thesis focused on the study of controlled polymerization of pentafluorophenyl methacrylate (PFPMA) which appeared to be challenging. Furthermore, along with the optimization of polymerization in solution was the investigation of surface-initiated polymerization of this monomer from PET surface. Besides, polymerization of p-nitrophenyl methacrylate (NPMA) and copolymerization of the two active esters by Cu(0)-mediated RDRP were also examined. In addition, polymer post-modification of obtained (co)polymers with various compounds had been proven to be efficient, easy to perform. The structure and characteristics of obtained products were confirmed to match with expectations. It is remarkable that the post-modification can be done as sequential process, single or dual functionalization with several different essential oils, which are natural antibacterial or antioxidant compounds. On the other hand, the success in polymerization and post-modification of polymer of active esters in solution allowed the fabrication of different PET film grafted with polymers that are envisaged to have antiadhesion properties. Attempts to test such properties were also done against two model bacteria including Staphylococcus aureus and Pseudomonas aeruginosa to investigate if expectations are valid.
9

Synthèse et caractérisation de copolymères diblocs amphiphiles thermo- et CO2-stimulables / Synthesis and characterization of thermo- and CO2-responsive amphiphilic diblock copolymers

Lespes, Aurélie 16 December 2015 (has links)
L’objectif de cette thèse est d’étudier la synthèse et les propriétés d’auto-assemblage en milieu aqueux de copolymères « intelligents » capables de former des agrégats supramoléculaires en réponse à deux stimuli : la température du milieu et la présence de dioxyde de carbone (CO2). Pour cela, une gamme de copolymères diblocs amphiphiles composés d’un bloc hydrophile d’acrylate de polyethylèneglycol méthyléther) (PEGA) et d’un bloc stimulable contenant une distribution statistique d’unités PEGA et acrylate de diéthlèneglycol éthyléther (DEGA) (thermosensibles) et acrylate de diéthylaminoéthyle DEAEA (CO2-sensible), a été préparée par polymérisation radicalaire contrôlée par les nitroxydes (NMP). Dans un second temps, il a été mis en évidence que la température ainsi que la présence de CO2 dans la solution influencent le comportement auto-associatif des copolymères dans l’eau. Par la suite, le bloc hydrophile a été remplacé par une séquence de dextrane, ce qui a permis de préparer de nouveaux copolymères diblocs fonctionnels, stimulables par la température et le CO2. Dans ce cas, deux techniques de polymérisation radicalaire contrôlée (NMP et ATRP) ont été testées afin d’obtenir les copolymères possédant l’architecture la mieux définie possible. / This project aims to investigate the synthesis and properties of dual stimuli-responsive block copolymers able to self-assemble into supramolecular aggregates in response to two stimuli: the temperature and the presence of carbon dioxide in the aqueous solution. Therefore, a range of amphiphilic diblock copolymers composed of a hydrophilic block of polyethylene glycol methylether acrylate (PEGA) and a statistical block of PEGA, diethylene glycol ethyl ether acrylate (DEGA) and diethylaminoethyl acrylate (DEAEA) was prepared via nitroxide-mediated polymerization (NMP) and the level of control of each synthesis was studied. We evidenced that temperature and CO2 play a different role in the self-assembly of such block copolymers. Finally, the introduction of dextrane as hydrophilic block coming from renewable resources allows for the preparation of novel “smart” amphiphilic diblock copolymers. In order to synthesize these block copolymers with well-defined structure, both NMP and atom transfer radical polymerization (ATRP) were investigated in parallel.
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Modelagem de reatores de polimerização : deterministica e por redes neurais / Modelling of polymerization reactors : deterministic and by neural networks

Contant, Sheila 23 February 2007 (has links)
Orientador: Liliane Maria Ferrareso Lona / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Quimica / Made available in DSpace on 2018-08-08T09:34:01Z (GMT). No. of bitstreams: 1 Contant_Sheila_D.pdf: 2364843 bytes, checksum: 3e362baeba9fe60ca91b2f54bbcac57e (MD5) Previous issue date: 2007 / Resumo: Neste trabalho, foram estudados diferentes processos de polimerização: (1) homopolimerização do estireno e copolimerização do estireno com metacrilato de metila em emulsão via radical livre convencional e (2) homopolimerização do estireno em massa via radical livre no processo controlado/vivo mediado por nitróxido. A modelagem dos processos foi realizada por meio de duas abordagens diferentes: inicialmente, modelos determinísticos foram desenvolvidos para cada caso e, utilizando resultados gerados por esses modelos, redes neurais foram treinadas para a modelagem inversa dos processos. Na modelagem determinística, foram desenvolvidos programas computacionais para as polimerizações em emulsão e simulações foram realizadas para diferentes condições operacionais. Para a polimerização controlada em massa, foi utilizado um programa computacional da literatura ao qual foram introduzidas modificações. Em todos os casos, foram levantados extensos bancos de dados de parâmetros cinéticos para todos os componentes envolvidos. Para o trabalho com as redes neurais, foi utilizado um programa computacional previamente desenvolvido ao qual foram introduzidas modificações. Redes neurais foram utilizadas para modelagem inversa dos processos, sendo treinadas para a predição de condições operacionais capazes de levar à produção de polímeros com propriedades específicas. As duas metodologias utilizadas para a modelagem matemática foram capazes de extrair importantes e diferentes informações dos processos de polimerização estudados, mostrandose portanto ferramentas bastante interessantes e eficientes para aplicação na área de engenharia de polimerização / Abstract: In this work different polymerization processes were studied: (1) styrene homopolymerization and styrene/methyl methacrylate copolymerization in emulsion in the conventional freeradical process, and (2) styrene homopolymerization in bulk in the nitroxidemediated controlled/living freeradical process. Modelling was developed using two different approaches: initially deterministic models were developed in each case, and using results from these models neural networks were trained to the inverse modelling of the processes. In the deterministic modelling, computational programas were developed to the emulsion polymerizations, and simulations were performed for different operating conditions. A modified computational program from the literature was used in the controlled polymerization in bulk. In all cases, large databases of kinetic parameters to all the compounds present were searched. A modified computational program previously developed was used in the work with neural networks. Neural networks were used to the inverse modelling of the processes, and were trained to predict operating conditions that could lead to production of polymers with specific properties. The two methodologies used in the mathematical modelling were able to extract important and different information from the polymerization processes studied, showing its potential to an efficient aplication in the polymerization area / Doutorado / Desenvolvimento de Processos Químicos / Doutor em Engenharia Química

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