Download or read book A Study on the Utility of Group Transfer Polymerization in the Synthesis of Block and Graft Copolymers written by A. C. Nielsen and published by . This book was released on 1991 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Amphiphilic Polymer Co networks written by Costas S Patrickios and published by Royal Society of Chemistry. This book was released on 2020-04-23 with total page 347 pages. Available in PDF, EPUB and Kindle. Book excerpt: Amphiphilic polymer co-networks (APCNs) are a type of polymeric hydrogel, their hydrophobic polymer segments and hydrophilic components produce less aqueous swelling, giving better mechanical properties than conventional hydrogels. This new class of polymers is attracting increasing attention, resulting in further basic research on the system, as well as new applications. This book focuses on new developments in the field of APCNs, and is organised in four sections: synthesis, properties, applications and modelling. Co-network architectures included in the book chapters are mainly those deriving from hydrophobic macro-cross-linkers, representing the classical approach; however, more modern designs are also presented. Properties of interest discussed include aqueous swelling, thermophysical and mechanical properties, self-assembly, electrical actuation, and protein adsorption. Applications described in the book chapters include the use of co-networks as soft contact lenses, scaffolds for drug delivery and tissue engineering, matrices for heterogeneous biocatalysis, and membranes of controllable permeability. Finally, an important theory chapter on the modelling of the self-assembly of APCNs is also included. The book is suitable for graduate students and researchers interested in hydrogels, polymer networks, polymer chemistry, block copolymers, self-assembly and nanomaterials, as well as their applications in contact lenses, drug delivery, tissue engineering, membranes and biocatalysis.
Download or read book Controlled Synthesis of Block and Graft Copolymers by the Combination of Group Transfer and Living Carbocationic Polymerization written by Aniko Takacs and published by . This book was released on 1995 with total page 224 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Synthesis of Block Copolymers Via Group Transfer Polymerization written by William George Ruth and published by . This book was released on 1994 with total page 250 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Statistical Gradient Block and Graft Copolymers by Controlled Living Radical Polymerizations written by Kelly A. Davis and published by Springer. This book was released on 2014-03-12 with total page 192 pages. Available in PDF, EPUB and Kindle. Book excerpt: The design and the realisation of well defined polymer architectures has become an important goal in macromolecular science. The prerequisite for achieving this goal is the availability of controlled polymerisation reactions. Living anionic polymerisation was the first reaction fulfilling these requirements. Cationic polymerisation only came into play when it was realised that it was possible to create an equilibrium between active and dormant species with the fraction of the dormant species being far superior to that of active ones. A corresponding principle applies to controlled radical polymerisation per formed in quite a number of modes such as nitroxide mediated polymerisation (NMP), atom transfer radical polymerisation (ATRP), reversible addition frag mentation chain transfer (RAFT) or catalytic chain transfer (CCT) reactions. All of these variants of controlled radical polymerisation lead to well defined archi tectures with the particular advantage that a much larger number of monomers are suitable and the reaction conditions are much less demanding than those of living ionic polymerisation reactions. Although in controlled radical polymerisation, termination reactions cannot be excluded completely, they are limited in their extent and consequently the mol ecular weight is controlled, the polydispersity index is small and functionalities can be attached to the macromolecules. These features are indicative of the real isation of well defined polymer architectures such as block copolymers, star shaped and comb shaped copolymers.
Download or read book Block and Graft Copolymers written by R. J. Ceresa and published by . This book was released on 1962 with total page 224 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Controlled living Polymerizations written by Christina Troeltzsch and published by . This book was released on 2003 with total page 568 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Biopolymer Grafting Synthesis and Properties written by Vijay Kumar Thakur and published by Elsevier. This book was released on 2017-09-27 with total page 596 pages. Available in PDF, EPUB and Kindle. Book excerpt: Biopolymer Grafting: Synthesis and Properties presents the latest research and developments in fundamental of synthesis and properties of biopolymer-based graft copolymers. The book presents a broad overview of the biopolymer grafting process, along with trends in the field. It also introduces a range of grafting methods which lead to materials with enhanced properties for a range of practical applications, along with the positives and limitations of these techniques. The book bridges the knowledge gap between the scientific principles and industrial applications of polymer grafting. This book covers synthesis and characterization of graft-copolymers of plant polysaccharides, functional separation membranes from grafted biopolymers, and polysaccharides in alternative methods for insulin delivery. Recent trends and advances in this area are discussed, assisting materials scientists and researchers in mapping out the future of these new "green" materials through value addition to enhance their use. - Introduces polymer researchers to a promising, rapidly developing method for modifying naturally derived biopolymers - Provides a one-stop shop covering synthesis, properties, characterization and graft copolymerization of bio-based polymeric materials - Increases familiarity with a range of biopolymer grafting processes, enabling materials scientists and engineers to improve material properties and widen the range of potential biopolymer applications
Download or read book Polysaccharide Based Graft Copolymers written by Susheel Kalia and published by Springer Science & Business Media. This book was released on 2013-05-23 with total page 358 pages. Available in PDF, EPUB and Kindle. Book excerpt: Renowned experts give all essential aspects of the techniques and applications of graft copolymers based on polysaccharides. Polysaccharides are the most abundant natural organic materials and polysaccharide based graft copolymers are of great importance and widely used in various fields. Natural polysaccharides have recently received more attention due to their advantages over synthetic polymers by being non-toxic, biodegradable and available at low cost. Modification of polysaccharides through graft copolymerization improves the properties of polysaccharides. Grafting is known to improve the characteristic properties of the backbones. Such properties include water repellency, thermal stability, flame resistance, dye-ability and resistance towards acid-base attack and abrasion. Polysaccharides and their graft copolymers find extensive applications in diversified fields. Applications of modified polysaccharides include drug delivery devices, controlled release of fungicides, selective water absorption from oil-water emulsions, purification of water etc.
Download or read book Utilization of Atom Transfer Radical Polymerization for Synthesis of Graft Copolymer of Natural Rubber and Poly methylmethacrylate written by Lapporn Vayachuta and published by . This book was released on 2009 with total page 191 pages. Available in PDF, EPUB and Kindle. Book excerpt: Atom Transfer Radical Polymerization (ATRP) technique was applied for synthesis of natural rubber-grafted-poly(methyl methacrylate) (NR-g-PMMA). Active sites on macromolecular chains of NR were created by fixation of bromoalkyl groups via a two-step chemical modification: partial epoxidation on unsaturated carbon-carbon bonds, followed by nucleophilic addition of a bromoalkyl-functionalized carboxylic acid on the oxirane rings of the epoxidized natural rubber (ENR) obtained. The resulting bromoalkyl-functionalized rubber was then used as macroinitiator to initiate the ATRP of methyl methacrylate (MMA) from NR chains by varying reaction conditions. The study was successively envisaged with 4-methyloct-4-ene (a model molecule of NR repeating unit), a synthetic cis-1,4-polyisoprene, and natural rubber. In the first part, the feasibility of the grafting reaction is verified by studying the ATRP of MMA from model molecules of bromoalkyl-functionalized 1,4-polyisoprene units. The model of the 1,4-polysisoprene unit, 4-methyloct-4-ene, is transformed in various models of bromoalkyl-functionalized 1,4-polyisoprene units via a chemical modification procedure carried out in two-steps: epoxidation performed with m-chloroperbenzoic acid (CPBA) followed by the addition of the bromoalkyl-functionalized carboxylic acid (2-bromopropionic acid, A1, or 2-bromo-2-methylpropionic acid, A2) on the oxirane ring formed. The addition of the acid occurs according to an SN2 mechanism with fixation of the acid group on the less substituted carbon of the oxirane ring and is competed with a secondary reaction of rearrangement of oxirane ring, leading to the formation of two allyl alcohols. The yield of the addition depends on the acidity of the carboxylic acid used. Afterwards, resulting O-(2-hydroxy-2-methyl-1-(n-propyl)pentyl)-2-bromopropionate and O-(2-hydroxy-2-methyl-1-(n-propyl)pentyl)-2-bromoisobutyrate, were used to initiate the ATRP of MMA at 90°C in toluene using Cu(I)Br complexed with a polyamine ligand. Several ligands were tested: N-(n-octyl)-2-pyridylmethanimine (NOPMI), N-(n-octadecyl)-2-pyridylmethanimine (NODPMI), and 1,1,4,7,7-pentamethyldiethylenetriamine (PMDETA). A good control of molecular weights (SECn,M) and polydispersity indexes (PDI) were obtained with O-(2-hydroxy-2-methyl-1-(n-propyl)pentyl)-2-bromoisobutyrate as the initiator in presence of CuBr/NOPMI as catalytic system. In the second part, the synthetic cis-1,4-polyisoprene (PI) is transformed into a bromoalkyl-functionalized polyisoprene (PI-Br) macroinitiator using a two-step chemical modification procedure similar to that used for synthesis of the model. PI was partially epoxidized using CPBA in dichloromethane, and then the epoxidized PI (EPI) obtained was reacted with A2. The addition of the acid occurs according to an SN2 mechanism with fixation of the acid group on the less substituted carbon of the oxirane ring ([beta]-addition) and is competed with rearrangement reactions of oxirane rings, leading to external allyl alcohol. SECn,M and PDI of PMMA grafts were determined by Size Exclusion Chromatography after separation from the PI backbone by hydrolysis of the ester bond using trifluoroacetic acid. An internal first order kinetic plot with respect to monomer and an increase of SECn,M with MMA conversion were observed using Cu(I)Br complexed with bidentate (NOPMI and NODPMI) and tridentate (PMDETA) ligands, as catalytic systems. With bidentate ligands, the PDI of grafts is better controlled. Moreover, the control of SECn,M and PDI of PMMA grafts was affected by increasing the degree of initiating units in PI-Br. In the last part, NR is used as a starting material. It was partially epoxidized in ENR in latex medium by reaction with performic acid generated in-situ from formic acid and hydrogen peroxide, and then ENR was transformed in bromoalkyl-functionalized NR (NR-Br) by nucleophilic addition of A2 on the oxirane rings. The addition of the acid is similar to that observed during the studies performed with 4-methyloct-4-ene and PI. Resulting NR-Br was then used to initiate the graft polymerization of MMA from NR chains using normal ATRP in toluene solution and in aqueous dispersed medium, respectively. AGET-ATRP was also considered in aqueous dispersed medium to study the effect of water for further ATRP graft copolymerization studies with NR latices. By normal ATRP in toluene solution, the termination reactions by recombination decreased as MMA concentration deceased, from 30 wt% to 10 wt%. PDIs of PMMA grafts vary in range from 1.7 (at 8.1 % MMA conversion) to 2.0 (at 52.0 % MMA conversion). A better control of the SECn,M and PDI of PMMA grafts was obtained by using normal ATRP in aqueous dispersed medium, more especially when CuBr was complexed with NODPMI. In these conditions, PDIs of PMMA grafts were low (closed to 1.5 at low MMA conversion). In AGET-ATRP performed in aqueous dispersed medium, it was shown that the efficiency of graft copolymerization is affected by the concentration in ascorbic acid used as reducing agent. The chemical structures obtained were characterized by FT-IR, and by 1H and 13C NMR. The thermal properties of the graft copolymers synthesized were studied by Differential Scanning Calorimetry (DSC). The presence of two Tgs, at about -14°C and 99°C respectively, on the DSC curves when the amounts of PMMA in NR-g-PMMAs are higher than 65 wt%, shows that these materials adopt a biphasic morphology.
Download or read book Papers Presented at the Meeting written by American Chemical Society. Division of Polymer Chemistry and published by . This book was released on 1998 with total page 1310 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Functionalization of Polyolefins written by T. C. Chung and published by Academic Press. This book was released on 2002-02-28 with total page 296 pages. Available in PDF, EPUB and Kindle. Book excerpt: Summarizes the significant experimental results on the functionalization of polyolefins and classifies them into several chemical methods. This book also provides information on the functional polyolefin materials. It covers: chemical approaches in the functionalization of polyolefins, and polyolefin materials and their potential applications.
Download or read book Block and Graft Copolymerization written by R. J. Ceresa and published by . This book was released on 1976 with total page 430 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Polymerization written by Ailton De Souza Gomes and published by BoD – Books on Demand. This book was released on 2012-09-12 with total page 440 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book comprises the contributions of several authors in the area of polymer characterization by atomic force microscopy of the polymer network structure formed in Ferroelectric Liquid Crystals Cells; polymerization by microwave irradiation method of starch/acrylic acid/acrylamide; polymerization of olefins; emulsion polymerization; ring opening polymerization; cationic polymerization of vinyl monomers ; block and graft copolymerization by controlled/living polymerization; fabrication of doped microstructures by two-photon polymerization; rheology of biomaterials; plant cell wall polymers; polyADP-Ribosylation in postfertilization and genome reprogramming . We hope that this book will help inspire readers to pursue study and research in this field.
Download or read book The Role of Group Transfer Polymerisation in Block Copolymer Synthesis written by Janet Grigor and published by . This book was released on 1990 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Biopolymer Grafting Applications written by Vijay Kumar Thakur and published by Elsevier. This book was released on 2017-09-19 with total page 542 pages. Available in PDF, EPUB and Kindle. Book excerpt: Biopolymer Grafting: Applications presents the latest research and developments in the practical application of these methods in industry, both to enable polymer scientists and engineers to keep up with the latest research trends, as well as to propose ideas for further research and application. Research into bio-based polymers has become increasingly prevalent. However, due to challenges related to the properties of these materials compared to synthetic polymers—such as their resistance to chemicals or weather—uptake has not dramatically increased yet. As a result, improvements in surface modification of bio-polymers through graft copolymerization are enormously important, because they will widen the scope of their applications. Relevant industries for application of these methods include automotive, construction, food, packaging, agriculture, textiles and paper. This book provides an overview of the developments made in the area of biopolymer-based graft polymers. Advantages, disadvantages and suggestions for future works are discussed, assisting materials scientists and researchers in mapping out the future of these new "green" materials through value addition to enhance their use. Helps researchers and product developers understand the applications and limitations of biopolymer copolymers or copolymers of natural polymers Offers a roadmap to future applications development in a range of different industries, including automotive, biomedical and packaging Increases familiarity with a range of biopolymer grafting processes, enabling materials scientists and engineers to improve material properties and widen the range of potential biopolymer applications
Download or read book Precision Synthesis of Complex Macromolecular Architectures of Gaseous Monomers and Their Property Studies written by Vignesh Vasu and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The thesis work is split into five major chapters, viz. metal catalyzed polymerization of 1,3 butadiene, various protocols for synthesis of Poly(vinylidenefluoride) block copolymers, Copper (0) metal mediated iodine degenerative transfer controlled radical photo emulsion VDF homopolymerization, synthesis of 2,3,3,3 - tetrafluoropropene (TFP) homo, random and block copolymers, metal catalyzed interconversion of inactive perfluorohalides. Controlled radical polymerization of 1,3 butadiene was successfully achieved by using various group 8 and group 10 metal complexes such as the Fe,Ni, Run+1X3/(Nitrogen, Oxygen, Halide, Phosphine) ligand complexes. First instance of photo mediated polymerization of 1,3 butadiene were developed for Fe-complexes. A library of complex PVDF block copolymer architecture were synthesized by Mn2(CO)10 catalyzed quantitative activation of the PVDF-CF2-CH2-I and PVDF-CH2-CF2-I chain ends, and their properties were studied. Metal-free organo photocatalyst mediated controlled radical polymerization of the second block in PVDF block copolymers was achieved, and the kinetics of polymerization and chain end activation were studied in detail. Novel poly(TFP) homopolymer, random and block copolymer with VDF architectures were synthesized by Cu(0), Mtx(CO)y catalyzed radical polymerization. Rational selection of parameters such as the nature of the solvent, temperature, metal ligand complexes and various additives was evaluated to optimize the kinetic parameters for successful interconversion of RFCl, RFBr and RFI substrates.
