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Showing 1 to 20 of 29 for “"living polymerization"”.
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Living Polymerization for the Introduction of Tailored Hydrogen Bonding
… 3-(t-butyldimethylsilyloxy)-1-propyllithium, in living anionic polymerization of isoprene was used to yield well-defined chain end functional macromolecules. Using both initiating systems, polymers with good molar mass control and narrow molar mass distributions were obtained and well-defined …
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Non-Covalent Interactions in Block Copolymers Synthesized via Living Polymerization Techniques
… and end-functional polymers synthesized via living polymerization techniques such as nitroxide mediated polymerization and anionic polymerization. The influence of non-covalent association on the structure/property relationships of these materials were studied in terms of physical properties …
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Early transition metal catalysts for the living polymerization of olefins and alkynes
… ligand were prepared and employed in the polymerization of 1-hexene. Hafnium Ziegler-Natta catalysts containing the [(2,6- X2C6H3NHCH2)2C(CH3)(2-C5H4N)] ([Arx2NPy]2-) (X = Cl or F) ligand were also prepared for use in 1-hexene polymerization studies. Compounds of the type [Ligand]MR2 (R = …
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Synthesis of well-defined single and multiphase polymers using various living polymerization methods
… (PDMS) macromonomers were synthesized using living polymerization techniques. The PDMS macromonomers were prepared by the anionic ring-opening polymerization of hexamethylcyclotrisiloxane followed by termination with a functionalized chlorosilane derivative. The methacryloyloxy functionalized …
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Design and synthesis of protein mimetics via living polymerization of β-sheets-forming n-carboxyanhydride
Submission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2024-08-01
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Polyenes by regioselective, living polymerization using molybdenum alkylidene bis(carboxylate) initiators and Ziegler-natta catalysis employing new zirconium diamido complexes
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemistry, 1997.
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Living cationic polymerization
The kinetics of the polymerization of styrene iniated by 1-chloro-1-phenyltehane/tin (IV) chloride in the presence of tetrabutylammonium chloride have been studied. Dilatometry studies at 25 °C were conducted and the orders of reaction were established. Molecular weight studies were conducted for …
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Synthesis and Characterization of Novel Polymers for Functional and Stimuli Responsive Silicon Surfaces
… a variety of novel functionalized polymers using living polymerization techniques to achieve functional and stimuli responsive coatings on silica surfaces are described. Since microscopic features on a surface influence the overall wetting properties of the surface, a systematic investigation of …
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Synthesis and characterization of hafnium and molybdenum bifunctional initiators for the preparation of triblock copolymers
… the resulting complex was an initiator for the living polymerization of 1-hexene, with the exception of a slight initiation effect. Five linker molecules were investigated for the preparation of bifunctional hafnium mixed alkyl complexes. One complex synthesized, disilyl[(MesNpy)HfMe]2 …
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Amino acid N-carboxyanhydrides and polypeptides: Controlled polymerization, properties and applications
… of my Ph.D. research is to develop controlled/living polymerization techniques of α-amino acid N-carboxyanhydrides (NCAs) and synthetic polypeptides based materials. Polypeptides are a class of emerging biomaterials receiving increasing interests for various applications including drug …
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Investigation of nitroxide-mediated thermal and photochemical reactions of living free radical polymerization.
… presented in this thesis deals primarily with living free radical polymerization (LFRP). Two main specific areas of this process have been studied; thermal and photochemical reaction sequences. Stoichiometric unimolecular initiators were found to be ideal probes for studying the reactions …
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Novel Approaches To The Synthesis of Clicked Block Copolymers
… their unique properties. With the development of living polymerization techniques, the synthesis of block copolymers with controlled molecular weights and unique architectures has reached an all time high. Here a novel approach to the synthesis of block copolymers, namely …
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Synthesis and characterization of m-aminophenoxide functionalized poly(tetramethylene oxide)
… was to functionalize bifunctional cationic living poly(tetramethylene oxide) (PTMO) with m-aminophenoxide to produce aromatic amine telechelic PTMO of controlled molecular weight and narrow molecular weight distribution. TrifHc anhydride was used to initiate a bifunctional cationic living …
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Synthesis of novel methacrylate-containing polymers by anionic polymerization
The advent of anionic "living" polymerization in the late 1950’s lead to developments in synthetic control not yet approached by other polymerization mechanisms. Parameters such as molecular weight, molecular weight distribution, stereochemistry, chain end functional groups, polymer architecture …
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Applications of ROMP Polymers
… (SPPs), was developed by ring-opening metathesis polymerization (ROMP) based on monomers containing recognition groups that display restricted rotation. We could modulate the binding properties of the SPPs by heating in polar or non-polar solvents (water/acetonitrile). The SPPs are also able to …
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Thermo-responsive Graft Copolymers based on Poly(Methyl Vinyl Ether): from Synthesis to Evaluation
… emerged from this work is that the controlled/living polymerization methods developed so far eliminate the limits in the design of novel types of graft copolymers with potential applications such as drug carriers, switchable amphiphiles, mineralization templates, etc... Several synthetic …
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Synthesis, characterization and kinetic investigations of heterophase materials prepared using group transfer polymerization
… preparation of blocks and grafts. Group Transfer Polymerization (GTP) is a relatively new synthetic method which provides a means to obtain poly(alkyl acrylate)s and poly(alkyl methacrylate)s via a "living" mechanism over a broad temperature range. The degree of control over molecular weight and …
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The ring opening polymerization of ring strained cyclic ethers
The kinetics and mechanisms of the ring-opening polymerization of oxetane were studied using cationic and coordinated anionic catalysts. The cationic initiators used were BF30Et2!/ethanol, BF30Et2!/ethanediol and BF30Et2/propantriol. Kinetic determinations with the BF30Et2/diol system indicated …
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Living cationic polymerization of isobutene
The polymerization of isobutene initiated by 1-chloro-1-phenylethane has been investigated, and molecular weight studies conducted using size exclusion chromatography. Polymerizations carried out in a 40/60 (v/v) mixture of dichloromethaneIcyclohexane, using titanium (IV) chloride as a catalyst in …
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Ring-opening Metathesis Polymerization for the Creation of Responsive Colloids and Surfaces
Ring-opening metathesis polymerization (ROMP) is a well-controlled living polymerization method and has been widely used to synthesize various polymer materials. This thesis investigates the use of ROMP in the creation of responsive materials, including photonic polymer colloids and …
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