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Showing 1 to 20 of 357 for “"Ring-opening"”.
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Self-Condensing Ring-Opening Metathesis Polymerization
Ring-opening metathesis polymerization (ROMP) is a great tool for synthesizing polyolefin materials with different topologies, including hyperbranched polymers—polymers with high degrees of branching and many end groups. However, hyperbranched polymer synthesis via ROMP is challenging due to …
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The Ring-opening Polymerisations of Cyclic Olefins
The ring opening polymerisations of cyclic olefins were investigated using a catalyst system of tungsten hexachloride and aluminium tri-isobutyl. The cyclic olefins investigated were cyclooctene and cyclopentene. The monomers were purified and attempts were made to remove conjugated dienes that …
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Borinic Acid-catalyzed Ring-opening of Epoxy Alcohols
… catalysis has been used by our group to effect ring-opening and rearrangement reactions of 2,3-epoxy alcohols via reversible borinate ester formation. This work focuses on expanding the mode of borinic acid catalysis to the activation of 3,4-epoxy alcohols for regioselective ring-opening …
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Metal-Free Photoredox-Mediated Ring Opening Metathesis Polymerization
Metal-free, photoredox-mediated ring-opening metathesis polymerization (MF-ROMP) is a novel approach to the synthesis of ROMP polymers. Whereas traditional, metal-mediated ROMP uses well-defined transition metal-alkylidene initiators in stoichiometric amounts, MF-ROMP uses a photo-oxidant to …
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Studies on the Ring Opening Polymerisation of Cyclopentene
… process. Oxidation state studies showed that during the polymerisation tungsten existed in at least two oxidation states. Subsequently a monometallic catalyst system - WC16/O2 - capable of polymerising cyclopentene, was developed. Infra-red studies showed that the product was again a …
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The cationic ring-opening polymerization of cyclic ethers
The kinetics and mechanisms of ring opening polymerization and copolymerizntion of different cyclic ethers were studied using mainly a cationic system of iinitiation. BF30Et2/ethanediol. The cyclic ethers reacted differently showing that ring strain and basicity are the main driving forces in …
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Macrocyclic Monomers: Synthesis, Characterization and Ring-opening Polymerization
… discovery of high yield synthesis and facile ring-opening polymerization of cyclic polycarbonate; the need for a technique to solve the tough processibility problem of high performance polymers. This work was intended to address the following aspects in the cyclic poly(ether ketone) or sulfone …
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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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Functional Polymer Materials: From Iptycenes to Ring-Opening Polymerizations
… In Chapter 3, we describe the living cationic ring-opening polymerization of a 2-alkylthio-2-oxazoline as a general platform for postpolymerization modification. Mild substitution conditions provide broad functional group tolerance, constituting a versatile postpolymerization modification …
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Development of Controlled Ring-Opening Polymerization of O-Carboxyanhydrides
… to summarize my research on the development of ring-opening polymerization (ROP) of O-carboxyanhydrides (OCAs) to synthesize functionalized, degradable polyesters. Biodegradable polyesters are promising alternatives to conventional petroleum-based non-degradable polyolefins and they are widely …
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Synthesis of functionalized polyamide 6 by anionic ring-opening polymerization
… a functionalizable primary amine) via anionic ring-opening polymerization. By using this strategy, we describe: (i) the synthesis of thermally more stable fluorinated polyamide 6 having a hydrophobic surface; (ii) the synthesis of polyamides 6 bearing pendant cinnamoyl groups, which are thermo- …
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Nuovi catalizzatori per l'idrogenazione, l'idrogenolisi/ring-opening di composti aromatici policiclici
… complete hydrogenation process with a selective ring opening (SRO) reaction of the naphthenic rings. The SRO can be defined as naphthene ring-opening to form compounds with high cetane number, but without any carbon losses. Controlling the interconversion of six- and five- membered rings via an …
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Abnormal Ring Expansion and Ring Opening Reactions of Polycyclic Aziridinium Salts
Made available in DSpace on 2014-12-09T17:36:46Z (GMT). No. of bitstreams: 1 7020952.pdf: 2995112 bytes, checksum: 8e7ee1ff79eda4f26fde61893c1977a3 (MD5) Previous issue date: 1970
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The photochemical and mechanochemical ring opening of cyclobutene from first principles
… of a pericyclic reaction is the electrocyclic ring opening of cyclobutene. The stereochemical outcome of this reaction can typically be predicted using the Woodward-Hoffmann rules, which are based on conservation of orbital symmetry. According to these rules, the thermal ring opening reaction …
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Dual-component systems for storable frontal ring-opening metathesis polymerization resins
Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2023-04-12 without embargo terms
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Accessing Model, Functional Polyolefins and Polyolefin Copolymers with Ring-Opening Metathesis Polymerization
… using traditional polymerization methods. Ring-opening metathesis polymerization (ROMP) is a useful tool for achieving this goal as the catalysts are often tolerant to a wide range of functional groups, and the polymerizations are typically well-controlled making polymers with moderate …
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Indium complexes and their role in the ring-opening polymerization of lactide
… of a series of chiral indium complexes bearing a tridentate NNO ligand are reported. The ligand 2-[[[(dimethylamino)cyclohexyl]amino]methyl]- 4,6-bis(tert-butyl) phenol (H₂NNO) was synthesized via a previously published procedure and bound to indium by both a protonolysis and salt …
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Synthesis, Characterization, and Ring -Opening Metathesis Polymerization Activity of Pentamethylcyclopentadienyl Osmium Complexes
Several acetonitrile complexes have been prepared; among these are [Cp*Os(CH 3CN)3][PF6], [CP*Os(PPh3)2(CH 3CN)][PF6], and [Cp*Os(COD)(CH3CN)]-[PF6 ]. Addition of 1,3-cyclooctadiene to Cp*2Os2Br 4 in refluxing ethanol affords the allyl complex Cp*Os(eta 3-C8H13)Br2. Treatment of the dimethyl …
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Development of Self -Healing Polymer Composites and Photoinduced Ring -Opening Metathesis Polymerization
… in performing Photoinduced Ring Opening Metathesis Polymerization (PROMP) is demonstrated. Polymerization of norbornene and dicyclopentadiene has been performed, showing the simplicity and ease of this procedure. The resulting poly(norbornene) shows high trans content (85%) …
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