Download or read book Synthesis and Properties of Novel Semi fluorinated Block Copolymers Via Cu II mediated Photo induced RDRP written by Yongguang Li and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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.
Download or read book Part I Morphology Transformation of Block Copolymer Micelles Containing Quantum Dots in the Corona written by Meng Zhang and published by . This book was released on 2013 with total page 378 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Advances in Aqueous Cu 0 mediated RDRP written by Fehaid Alsubaie and published by . This book was released on 2017-04-02 with total page 268 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Novel Fluorinated Block Copolymers by Selective Chemical Modification written by Drew Alan Davidock and published by . This book was released on 2004 with total page 598 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Synthesis of Block Copolymers by Combination of Photoinduced and Atom Tranmsfer Radical Polymerization Routes written by İrem Erel and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Novel Heat resistant Materials written by Jingjing Xu and published by . This book was released on 2002 with total page 474 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Les Vrais Incroyables ou les M tamorphoses modernes written by and published by . This book was released on 1798 with total page 35 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Synthesis Characterization and Self assembly of Amphiphilic Block Copolymers written by Xiaojun Wang and published by . This book was released on 2012 with total page 250 pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation presents a review on state-of-the-art research of well-defined charged block copolymers, including synthesis, characterization, bulk morphology and self-assembly in aqueous solution of amphiphilic block polyelectrolytes. In Chapter 1, as a general introduction, experimental observations and theoretical calculations devoted towards understanding morphological behavior in charged block copolymer systems are reviewed along with some of the new emerging research directions. Further investigation of charged systems is urged in order to fully understand their morphological behavior and to directly target structures for the tremendous potential in technological applications. Following this background, in Chapters 2, 3, 4 and 5 are presented the design and synthesis of a series of well-defined block copolymers composed of charged and neutral block copolymers with full characterization: sulfonated polystyrene-b-fluorinated polyisoprene (sPS-b-fPI) and polystyrene-b-sulfonated poly(1,3-cyclohexadiene) (PS-b-sPCHD). Their bulk morphological behaviors in melts and self-assembly of sPS-b-fPI, PS-b-sPCHD in water were investigated. Some unique behaviors of sPS-b-fPI were discovered. The mechanisms for formation of novel nanostructures in aqueous solution are discussed in details in Chapter 4. Spherical and vesicular structures were formed from strong electrolyte block copolymers, e.g. PS-bsPCHD. Detailed light scattering and transmission electron microscopy were applied to characterize these structures. The abnormal formation of vesicles as well as microstructure effects on self-assembly is discussed in Chapter 5. In Chapter 6, we describe the successful synthesis of a well-defined acid-based block copolymers containing polyisoprene while maintaining the integrity of the functionality (double bonds) of polyisoprene. A general purification method is also presented in order to remove homo polyisoprene, polystyrene, and PS-b-PI in the di-, and tri-block copolymers. The self-assembly of PS-b-PI-b-PAA triblock terpolymers was studied in order to form multicompartmental structures in aqueous environments. In the last Chapter 7, detailed synthesis and characterization of a novel conjugate: poly(L-leucine) grafted hyaluronan (HA) (HA-g-PLeu) are presented. This work describes a new method to synthesize HA-g-PLeu via a "grafting onto" strategy. Due to the amphiphilic nature of this graft copolymers, a "local network" formed by self-assembly which was characterized by atomic force microscopy and light scattering. The secondary structure of the polypeptide was revealed by circular dichroism.
Download or read book Block Copolymer Templated Nitrogen enriched Nanocarbons written by Mingjiang Zhong and published by . This book was released on 2013 with total page 315 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Reversible-deactivation radical polymerization (RDRP), also referred to as controlled/"living" radical polymerization (CRP) has been developed over the past 20 years. RDRP promotes the synthesis of well-defined polymeric materials with controlled molecular weights and molecular weight distributions, complex topologies and functionalities. In the past decade, the Matyjaszewski and Kowalewski groups pioneered the work of synthesizing nanostructured carbon by pyrolysis of polyacrylonitrile (PAN) containing polymeric precursors prepared via RDRP. My contribution to this topic was primarily focused on the following aspects: (1) optimization of the synthetic procedure, (2) deeper investigation of the structures, (3) exploration of the surface chemistry with particular emphasis of nitrogen functionality, (4) and energy related applications. This thesis first focuses on addressing current challenges in RDRP particularly in atom transfer radical polymerization (ATRP), one of the most robust RDRP techniques. Based on the development of a deep mechanistic understanding of RDRP's, ATRP was then used for the synthesis of PAN containing block copolymers followed by applying a series of analytical tools to provide detailed physical characterization. Finally, these materials were utilized as precursors for the formation of nanocarbons that were evaluated in various energy related applications. The development of nanostructured carbon materials from PAN precursors is discussed in Chapter 1. Particular emphasis is placed on the rational structural design of PAN containing polymeric precursors developed in the Matyjaszewski and Kowalewski groups, while the detailed synthetic methodology will be discussed in the subsequent chapters. Controlled synthesis is the prerequisite for many applications. The successful preparation of block copolymers via RDRP requires preparation of a macroinitiator with preserved chain end functionality (CEF). Work described in Chapter 2 resulted in the establishment of a universal rule for quantifying the CEF in all RDRPs, which is also the most important criterion for determining the "livingness" and degree of control over the polymerization. The parameters affecting the level of CEF preservation are determined. Another challenge in ATRP is diminishing the concentration of catalyst employed during the polymerization procedure in order to reduce the cost and simplify the purification steps. Chapter 3 describes the systematic study of RDRP in the presence of zerovalent copper, which offers significant advantages in this regard. The contribution of all of the potential reactions occurring in an ATRP carried out in the presence of copper zero were evaluated, and a supplemental activator and reducing agent (SARA) ATRP mechanism is concluded to precisely describe this system. How to conduct and optimize SARA ATRP system is then demonstrated. Chapter 4 is focused on another aspect of the robust capability of ATRP : controlling the molecular weight distribution. Activator regeneration electron transfer (ARGET) ATRP was employed to prepare polystyrene-block-poly(methyl acrylate) copolymers with tunable dispersity in the range of 1.32 to 2.0 for each block. Knowledge attained from the studies discussed in Chapter 2 to 4 has been extensively utilized in the studies of nanocarbons. Chapter 5 discusses the preparation of a series of PAN containing diblock copolymers that were used as precursors for the preparation of nanocarbons. The block copolymers undergo phase separation and then the poly(n-butyl acrylate) serves as a sacrificial segment upon pyrolysis. Both thin film and bulk nanocarbons with diverse morphologies, resembling the original phase-separated copolymer precursors, were prepared. The carbonization of bulk copolymer precursors with branched PAN domains was of particular interest; which resulted in the formation of porous nanocarbons with large surface area and highly accessible nitrogen functionality originating from PAN. Chapter 6 illustrates how porosity and accessible nitrogen functionality in the nanocarbon introduced in Chapter 5 can be utilized for CO2 capture. The main emphasis was placed on the surface area and nitrogen content's influence on adsorption capacity and selectivity was studied. Chapter 7 discusses the application of PAN-derived nanocarbons as electrode materials for supercapacitors. Materials displaying both high energy density and high power density were achieved. This excellent performance was partially due to the mesoporous structure with high specific surface area, in combination with the pseudocapacitance originating from graphitic edge nitrogens. Evidence of electrochemical activity of the nitrogen heteroatoms provided the motivation to explore the performance of copolymer templated nanocarbon as an electrocatalyst for oxygen reduction, as described in Chapter 8. A desirable 4-electron transfer process with a low overpotential system was achieved by as-prepared nanocarbon film with porous morphology; which again, demonstrates one of the unique properties of nanocarbons prepared from PAN containing block copolymer precursors. Finally, a summary is provided in Chapter 9 and some future directions regarding synthesis and utility of heteroatom-enriched nanocarbons are discussed."--Pages ii-v.
Download or read book Copper Mediated Living Radical Polymerisation written by Amilcar Pillay Narrainen and published by . This book was released on 2003 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Synthesis and Solution Behavior of Doubly Responsive Hydrophilic Block Copolymers written by Xueguang Jiang and published by . This book was released on 2010 with total page 282 pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation presents the synthesis of stimuli-sensitive hydrophilic polymers, particularly doubly responsive hydrophilic block copolymers, by controlled radical polymerizations and the study of their solution behavior in water. By incorporating a small amount of stimuli-responsive groups into the thermosensitive block of a hydrophilic block copolymer, the lower critical solution temperature (LCST) of the thermosensitive block can be tuned by a stimulus and multiple micellization/dissociation transitions can be achieved by combining two external triggers. Chapter 1 describes the synthesis and thermosensitive properties of two new watersoluble polystyrenics with a short oligo(ethyl glycol) pendant from each repeat unit and the study of hydrophobic end group effects on cloud points of thermosensitive polystyrenics. Well-defined polymers were prepared from monomer-based initiators via nitroxide-mediated polymerization and the alkoxyamine end groups were removed by tri(n-butyl)tin hydride, yielding thermoresponsive polystyrenics with essentially no end groups. The results showed that hydrophobic end groups could significantly change the cloud points and the molecular weight dependences of cloud points of polystyrenics. Chapter 2 presents the synthesis of thermo- and light-sensitive hydrophilic block copolymers, poly(ethylene oxide)-b-poly(ethoxytri(ethylene glycol) acrylate-co-o-nitrobenzyl acrylate), and their responsive behavior in dilute aqueous solutions. Dynamic light scattering and fluorescence spectroscopy studies showed that these copolymers were molecularly dissolved in water at lower temperatures and self-assembled into micelles at temperatures above the LCST of the thermosensitive block. Upon UV irradiation, the o-nitrobenzyl group was cleaved and the LCST of the thermosensitive block was increased, causing the dissociation of micelles into unimers. The resultant copolymers underwent thermo-induced reversible micellization at higher temperatures. Chapter 3 describes multiple micellization/dissociation transitions of thermo- and pH-sensitive hydrophilic block copolymers, poly(ethylene oxide)-b-poly(methoxydi(ethylene glycol) methacrylate-co-methacrylic acid), in response to temperature and pH changes. The LCST of the thermosensitive block can be reversibly tuned and precisely controlled by solution pH. Chapter 4 presents the study on multiple sol-gel-sol transitions of a 20.0 wt % aqueous solution of poly(ethylene oxide)-b-poly(ethoxytri(ethylene glycol) acrylate-co-o-nitrobenzyl acrylate) induced by temperature changes and UV irradiation. The solution underwent thermo-induced sol-gel-sol transitions. Upon UV irradiation to dissociate micelles, the gel was transformed into a free-flowing liquid, which upon heating underwent sol-gel-sol transitions again.
Download or read book Synthesis and Properties of Novel Rf pluronic Pentblock Copolymers written by and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Synthesis of Novel Block Copolymer Dispersants for Water borne Pigments written by Xavier Bories-Azeau and published by . This book was released on 2003 with total page 402 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Novel Semiconductor Block Copolymers for Organic Electronic Devices written by Michael Sommer and published by . This book was released on 2009 with total page 232 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Synthesis and Properties of Block Copolymers written by Francis Leonard Dalton and published by . This book was released on 1956 with total page 141 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Synthesis and Characterization of Stimuli Responsive Block Copolymers Self assembly Behavior and Applications written by Michael Duane Determan and published by . This book was released on 2006 with total page 296 pages. Available in PDF, EPUB and Kindle. Book excerpt: Water-soluble stimuli responsive block copolymers are a rapidly emerging class of materials with great potential in biomedical and technological applications. In this work a novel class of pentablock copolymers are synthesized via atom transfer radical polymerization techniques and their stimuli-responsive self-assembly properties are characterized. Aqueous solutions of these materials are observed to form micelles and hydrogels in response to changes in both temperature and pH. Cryogenic transmission electron microscopy (cryo-TEM) and small angle neutron and X-ray scattering (SANS and SAXS) techniques are used to investigate the nanoscale structures formed by these pentablock copolymers in solution. The gel structure and mechanical properties are investigated with SANS and rheological techniques. The multi-responsive properties of these materials are utilized to formulate a stimuli responsive drug delivery formulation that exhibits thermoreversible gelation and pH dependent release rate of model drugs.
