Synthèse et étude des propriétés de nouveaux polymères amphiliples cationiques basés de systèmes organisés macromoléculaires PDF Download
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Author: Christine Damas
Publisher:
ISBN:
Category :
Languages : en
Pages : 216
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Book Description
The synthesis of two series of polymers containing hydrophilic parts close to the polymer backbone and aliphatic si de chains is described. Polymers (I) are obtained by copolymerization of 4-vinylpyridine and N-alkylacrylamide (alkyl chain containing 6-12 carbon atoms) followed by quaternization using methylbromide. Polymers (ID are poly(:B-alkyl-l-vinylimidazolium bromide), the alkyl side chains ofwhich contain 1 to 16 carbon atoms. Their aqueous solution properties have been studied by iscosimetry, fluorimetry. Solvatochromic effects and capability of hydrophobic molecules solubilization have been considered. The influence of the polymer chemical structure on the. hydrophobic microdomains formation is discussed. The solution behaviour of the polymers (II) is compared with that of a surface-active compound (3-hexadecyl-l-methylimidazolium bromide) taken as a -reference model for mimicking the polymeric amphiphilic units. The influence of the medium (water/methanol) and of polymer concentration in rich water solvent content on the microdomains formation is also examined. Microdomains in cOl1'olymers (I) appear at water contents much higher than in polymers (II). In a given ricH water medium, a precise concentration of polymer corresponding to the microdomains formation can he determined. This concentration is related to the global hydrophobicity of the copolymer (1). Polymers (ll) have been compared with their modeI. Unlike polymers (m, copolymers (1) are surface-active : this property is attributed to the more or less stable microdomains forcing the macromolecules to absorb at the interface. Finally the polymers (1) and (II) matrixes can be considered as microreactors in the catalyzed hydrophobic picolinic esters hydrolysis
Author: Christine Damas
Publisher:
ISBN:
Category :
Languages : en
Pages : 216
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Book Description
The synthesis of two series of polymers containing hydrophilic parts close to the polymer backbone and aliphatic si de chains is described. Polymers (I) are obtained by copolymerization of 4-vinylpyridine and N-alkylacrylamide (alkyl chain containing 6-12 carbon atoms) followed by quaternization using methylbromide. Polymers (ID are poly(:B-alkyl-l-vinylimidazolium bromide), the alkyl side chains ofwhich contain 1 to 16 carbon atoms. Their aqueous solution properties have been studied by iscosimetry, fluorimetry. Solvatochromic effects and capability of hydrophobic molecules solubilization have been considered. The influence of the polymer chemical structure on the. hydrophobic microdomains formation is discussed. The solution behaviour of the polymers (II) is compared with that of a surface-active compound (3-hexadecyl-l-methylimidazolium bromide) taken as a -reference model for mimicking the polymeric amphiphilic units. The influence of the medium (water/methanol) and of polymer concentration in rich water solvent content on the microdomains formation is also examined. Microdomains in cOl1'olymers (I) appear at water contents much higher than in polymers (II). In a given ricH water medium, a precise concentration of polymer corresponding to the microdomains formation can he determined. This concentration is related to the global hydrophobicity of the copolymer (1). Polymers (ll) have been compared with their modeI. Unlike polymers (m, copolymers (1) are surface-active : this property is attributed to the more or less stable microdomains forcing the macromolecules to absorb at the interface. Finally the polymers (1) and (II) matrixes can be considered as microreactors in the catalyzed hydrophobic picolinic esters hydrolysis
Author: Abdesselam Benjelloun
Publisher:
ISBN:
Category :
Languages : fr
Pages : 260
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Book Description
CE TRAVAIL DE RECHERCHE A ETE CONSACRE A L'ELABORATION DE NOUVEAUX POLYMERES AMPHIPHILES CATIONIQUES DERIVES DE LA 3-VINYLPYRIDINE. ILS SONT OBTENUS PAR POLYMERISATION RADICALAIRE, EN SOLUTION, DES SELS DE PYRIDINIUM CORRESPONDANTS. CETTE VOIE DE SYNTHESE NOUS A PERMIS D'OBTENIR DES HOMOPOLYMERES DE STRUCTURE BIEN DEFINIE ET DES COPOLYMERES FINAUX ENTIEREMENT QUATERNISES. POUR MIEUX CARACTERISER LE COMPORTEMENT DE CES POLYMERES EN SOLUTION AQUEUSE DILUEE, NOUS AVONS FAIT APPEL A DIFFERENTES TECHNIQUES PHYSICO-CHIMIQUES TELLES QUE LA VISCOSIMETRIE, LES EFFETS DE SOLVATOCHROMIE, LA SPECTROSCOPIE DE FLUORESCENCE DES ROTORS MOLECULAIRES, LA TENSIOMETRIE ET LA CRYO-MICROSCOPIE ELECTRONIQUE EN TRANSMISSION. UNE CORRELATION ENTRE LA STRUCTURE CHIMIQUE DE CES POLYMERES ET LEURS PROPRIETES PHYSICO-CHIMIQUES EN SOLUTION AQUEUSE A PU ETRE ETABLIE. NOUS AVONS, EGALEMENT, ETUDIE L'INFLUENCE DU MILIEU SOLVANT ET DE LA CONCENTRATION EN POLYMERE SUR LEUR COMPORTEMENT EN MILIEU AQUEUX. LES MESURES VISCOSIMETRIQUES REVELENT LA FORMATION DE MICRODOMAINES HYDROPHOBES A PARTIR DE FAIBLES TENEURS EN EAU. ELLES MONTRENT UN CHANGEMENT CONFORMATIONNEL QUI CORRESPOND A UNE MEILLEURE STABILITE DES MICRODOMAINES POUR UN TAUX CROISSANT EN MOTIFS 3VPC#1#6BR. LES MEMES EFFETS ONT ETE OBSERVES PAR FLUORESCENCE DES ROTORS MOLECULAIRES ET LES EFFETS SOLVATOCHROMIE QUI SE TRADUISENT PAR UN CHANGEMENT DE LA POLARITE DU MILIEU ENVIRONNANT LA SONDE UTILISEE. DES RESULTATS OBTENUS PAR CRYO-MET REVELENT UNE ORGANISATION PARTICULIERE DE L'HOMOPOLYMERE P3VPC#1#6BR EN FORME D'EMPREINTE DIGITALE. ENFIN L'APTITUDE DE CES MICRODOMAINES A INCORPORER DES SUBSTANCES HYDROPHOBES DANS L'EAU MAIS SOLUBLES EN MILIEU ORGANIQUE NOUS ONT CONDUIT A LES UTILISER EN TANT QUE MICROREACTEURS DANS LESQUELS PEUVENT SE DEROULER DES REACTIONS BIMOLECULAIRES D'HYDROLYSE D'ESTERS ACTIVES
Author: Fatiha Bezzaoucha
Publisher:
ISBN:
Category :
Languages : fr
Pages : 416
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Book Description
Dans le but d'approfondir les connaissances fondamentales entre la structure des polymères associatifs intramoléculaires (polysavons) et leurs propriétés physico-chimiques en milieux aqueux, trois nouvelles familles de polymères amphiphiles cationiques ont été synthétisées par deux méthodes complémentaires permettant une grande variabilité de structure. Les polymères obtenus sont des poly(méth)acrylamides en peigne avec des groupes latéraux de type ammonium quaternaire portant une chaîne alkyle de taille variable. Une étude du comportement physico-chimique de ces polymères en solution, par viscosimétrie et spectroscopie de fluorescence avec deux sondes aux caractéristiques complémentaires, montre qu'ils présentent des propriétés de polysavons qui varient progressivement avec la structure des polymères amphiphiles étudiés, notamment la longueur de la chaîne alkyle latérale, la taille de l'espaceur entre les deux sites polaires amide et ammonium quaternaire et la masse molaire moyenne en nombre. En parallèle, la tensiométrie a montré que ces polyamphiphiles ont une très faible activité à l'interface eau/air confirmant la prédominance de l'effet hydrophobe, alors que les modèles moléculaires correspondants présentent d'excellentes propriétés tensio-actives. Des films de Langmuir ont ensuite été réalisés dans le cadre de la première étude de cette importance sur des polyamphiphiles cationiques. Dans ce domaine également, la grande variabilité de structure des polymères a permis des observations originales et de dégager de nouvelles relations entre la structure du polymère et les caractéristiques des isothermes de compression obtenues.
Author: Jean-Marie Basset
Publisher: John Wiley & Sons
ISBN: 3527627103
Category : Science
Languages : en
Pages : 725
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Book Description
Covering everything from the basics to recent applications, this monograph represents an advanced overview of the field. Edited by internationally acclaimed experts respected throughout the community, the book is clearly divided into sections on fundamental and applied surface organometallic chemistry. Backed by numerous examples from the recent literature, this is a key reference for all chemists.
Author: Alexandru Grumezescu
Publisher: Academic Press
ISBN: 0128043784
Category : Science
Languages : en
Pages : 926
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Book Description
Encapsulations, a volume in the Nanotechnology in the Agri-Food Industry series,presents key elements in establishing food quality through the improvement of food flavor and aroma. The major benefits of nanoencapsulation for food ingredients include improvement in bioavailability of flavor and aroma ingredients, improvement in solubility of poor water-soluble ingredients, higher ingredient retention during production process, higher activity levels of encapsulated ingredients, improved shelf life, and controlled release of flavor and aroma. This volume discusses main nanoencapsulation processes such as spray drying, melt injection, extrusion, coacervation, and emulsification. The materials used in nanoencapsulation include lipids, proteins, carbohydrates, cellulose, gums, and food grade polymers. Applications and benefits of nanoencapsulation such as controlled release, protections, and taste masking will be explained in detail. Includes the most up-to-date information on nanoencapsulation and nanocontainer-based delivery of antimicrobials Presents nanomaterials for innovation based on scientific advancements in the field Provides control release strategies to enhance bioactivity, including methods and techniques for research and innovation Provides useful tools to improve the delivery of bioactive molecules and living cells into foods
Author: Xian Jun Loh
Publisher: Springer
ISBN: 9812871527
Category : Technology & Engineering
Languages : en
Pages : 229
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Book Description
This book presents the research involving in situ gelling polymers and can be used as a guidebook for academics, industrialists and postgraduates interested in this area. This work summaries the academic contributions from the top authorities in the field and explore the fundamental principles of in situ gelling polymeric networks, along with examples of their major applications. This book aims to provide an up-to-date resource of in situ gelling polymer research.
Author: Antonio Pizzi
Publisher: CRC Press
ISBN: 9004190937
Category : Technology & Engineering
Languages : en
Pages : 464
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Book Description
Wood adhesives are of tremendous industrial importance, as more than two-thirds of wood products in the world today are completely or partially bonded together using a variety of adhesives. Adhesive bonding offers many advantages over other joining methods for wood components, and there has been a great deal of R& D activity in devising new wood adhesives or improving the existing ones. The modern mantra in all industrial sectors is: "think green, go green," which has attracted much attention in the wood adhesive industry. Therefore, there is also a lot of research activity in synthesizing environmentally benign and human-friendly wood adhesives. This book is divided into four parts: Part 1: Fundamental Adhesion Aspects in Wood Bonding; Part 2: Synthetic Adhesives; Part 3: Environment-friendly adhesives; and Part 4: Wood Welding and General Paper. It addresses many different types of wood adhesives, as well as bonding (welding) of wood components without adhesives, a more recent development. The information contained in this book is valuable for individuals engaged in all aspects of wood adhesion and adhesives and, hopefully, will inspire new ideas in wood adhesives, a topic of vital industrial importance.
Author:
Publisher:
ISBN: 9780387134833
Category : Membranes (Biology)
Languages : en
Pages : 165
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Book Description
Author: Mark A. Prelas
Publisher: Springer Science & Business Media
ISBN: 9401155925
Category : Technology & Engineering
Languages : en
Pages : 378
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Book Description
Diamond-based composites, with their advantages of hardness, high Young's modulus and the like, have demonstrated new and unusual features, such as stability to high temperatures and pressure shocks and a large internal surface that can be controlled to offer customised electrical, magnetic and optical properties, leading to efficient filters, absorbents, sensors and other tools for environmental control and monitoring. The current book covers the synthesis of materials, their characterization and properties, trends in high pressure and high temperature technologies, low pressure technologies, basic principles of DBC material science, and future developments in electronics, optics, industrial tools and components, biotechnology, and medicine. Wide band-gap materials are considered, ranging from molecular clusters, nanophase materials, growth, processing and synthesis. The processing of composite based materials can be classified into six basic methods: in situ growth, high pressure/high temperature catalytic conversion; mix and sinter (c-BN plus metal-ceramic polymer mix); direct sintering; direct polymorphic conversion; shock detonation; and SHS sintering.
Author: Aleksey Kuznetsov
Publisher: BoD – Books on Demand
ISBN: 1839681799
Category : Science
Languages : en
Pages : 148
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Book Description
Azoles are a broad and promising class of five-membered heterocyclic compounds containing from one up to five nitrogen atom(s) that can also contain sulfur or oxygen atoms. Widely used as potent antifungal agents, various azole derivatives have also demonstrated many other promising biological properties. This book covers studies of several types of thiazole-based heterocyclic scaffolds, the development of 4-thiazolidinone and thiazole derivatives with heterocyclic fragments as potential candidates for new drugs against trypanosomiasis, numerous synthetic approaches for the synthesis of 1,2,3-triazoles, the application of N-azole, N,S-azole, and N,O-azole as well as their derivatives as retarders of metallic corrosion, and the integration of azoles in materials used for renewable energy processing and applications and wood treatment.
