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Znii And Cuii Unsymmetrical Formamidine Complexes As Effective Initiators For Ring Opening Polymerization Of Cyclic Esters
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Book Synopsis Zn(II) and Cu(II) Unsymmetrical Formamidine Complexes as Effective Initiators for Ring‐opening Polymerization of Cyclic Esters by :
Download or read book Zn(II) and Cu(II) Unsymmetrical Formamidine Complexes as Effective Initiators for Ring‐opening Polymerization of Cyclic Esters written by and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Co-ordination Chemistry, Kinetics and Mechanistic Studies of Ring-opening Polymerization of Cyclic Esters by Formamidine and Benzimidazolyi Mg (ll) and Zn(ll) Complexes by : Ekemini Daniel Akpan
Download or read book Co-ordination Chemistry, Kinetics and Mechanistic Studies of Ring-opening Polymerization of Cyclic Esters by Formamidine and Benzimidazolyi Mg (ll) and Zn(ll) Complexes written by Ekemini Daniel Akpan and published by . This book was released on 2016 with total page 358 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Titanium Complexes Based on Aminodiol Ligand for Ring Opening Polymerization of Cyclic Esters by : Dakshinamoorthy Deivasagayam
Download or read book Titanium Complexes Based on Aminodiol Ligand for Ring Opening Polymerization of Cyclic Esters written by Dakshinamoorthy Deivasagayam and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A series of titanium isopropoxides complexes coordinated by enantiopure, racemic, meso and diastereomeric aminodiol ligands have been prepared and characterized by spectroscopic techniques. The complexes were tested as initiators for the ring opening polymerization (ROP) of cyclic esters such as L/rac-lactide, caprolactone, butyrolactone and trimethylene carbonate via coordination-insertion mechanism. In lactide polymerizations, all complexes showed significant activity both in solution at 70°C and in bulk at 130°C with a good control. The complex derived from rac-aminodiol ligand gave partially heterotactic polylactide in ROP of rac-lactide, whereas all other complexes yielded atactic polylactides. For caprolactone polymerizations, all complexes were found to be effective initiators under both solution and bulk conditions (up to 60% monomer conversion was reached within 10 min in bulk condition at 70°C), again with good control. Kinetic studies of ROP of lactides and caprolactone in solution conditions have been investigated and showed a first kinetic order in monomer. Significant activities were also observed for (ROP) of butyrolactone and trimethylene carbonate. Block copolymers of caprolactone and lactides were successfully synthesized with these catalytic systems by sequential polymerization techniques. The complexes were also tested as initiators for the production of random copolymers containing caprolactone and lactides and a reverse order of reactivity was observed between lactide and caprolactone compared to homopolymerization.
Book Synopsis Ring-opening Polymerisation by : N. Spassky
Download or read book Ring-opening Polymerisation written by N. Spassky and published by iSmithers Rapra Publishing. This book was released on 1995 with total page 112 pages. Available in PDF, EPUB and Kindle. Book excerpt: The general features of ring-opening polymerisation, for example the dependence of polymerisability upon ring-strain, the significance of ring-chain equilibria, and the potential for formation of cyclic oligomers are outlined. An additional indexed section containing several hundred abstracts from the Rapra Polymer Library database provides useful references for further reading.
Book Synopsis Ring Opening Metathesis Polymerisation and Related Chemistry by : Ezat Khosravi
Download or read book Ring Opening Metathesis Polymerisation and Related Chemistry written by Ezat Khosravi and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 489 pages. Available in PDF, EPUB and Kindle. Book excerpt: Since the last ASI in Turkey in Sept. 1995, the olefin metathesis has made remarkable strong developments with an incredible speed in various directions. New catalyst systems have been developed which have resulted in the synthesis of novel materials. Other fascinating developments have been the new catalysts for stereoselective metathesis and catalysts with considerable functional group tolerance. These new catalysts in addition to Ring Opening Metathesis Polymerisation (ROMP) and Acyclic Diene Metathesis (ADMET) are now powerful tools for Ring Closing Metathesis (RCM) and have found many applications in the synthesis of natural products. A lot of information has been established about all aspects of the olefin metathesis and there is a vast literature concerning the process, covering the initiators, mechanistic features and applications of this reaction in organic and polymer synthesis. The NATO ASI on rd th ROMP and Related Chemistry took place in Polanica-Zdroj, Poland during 3 to 15 Sept. 2000, to highlight the developments in this area and to discuss the prospects and visions for the year 2000 and beyond. The aims of the ASI were: to provide a platform for dissemination of knowledge; to promote communication between people who have a serious interest in this field of chemistry; to help establishing international scientific contacts and to provide an opportunity for the scientists with an appropriate scientific background to learn of recent developments in this field of science. There were 15 lecturers and 67 participants in this NATO ASI.
Book Synopsis Synthesis of Al and Zn Complexes, and Their Catalytic Activity Toward the Ring-opening Polymerization of Cyclic Esters by : K. Bakthavachalam
Download or read book Synthesis of Al and Zn Complexes, and Their Catalytic Activity Toward the Ring-opening Polymerization of Cyclic Esters written by K. Bakthavachalam and published by . This book was released on 2014 with total page 338 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Ring-opening Polymerization by : Kenneth John Ivin
Download or read book Ring-opening Polymerization written by Kenneth John Ivin and published by . This book was released on 1984 with total page 632 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Ring-opening Polymerization by : Takeo Saegusa
Download or read book Ring-opening Polymerization written by Takeo Saegusa and published by . This book was released on 1977 with total page 368 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Mono(cyclopentadienyl)titanium Complexes as Initiators for Living Ring-opening Polymerization of Lactones by : Il'ya L. Rushkin
Download or read book Mono(cyclopentadienyl)titanium Complexes as Initiators for Living Ring-opening Polymerization of Lactones written by Il'ya L. Rushkin and published by . This book was released on 1993 with total page 118 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Biometal Catalyzed Ring-opening Polymerization of Cyclic Esters by : Osit Karroonnirun
Download or read book Biometal Catalyzed Ring-opening Polymerization of Cyclic Esters written by Osit Karroonnirun and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Biodegradable polyesters represent a class of extremely useful polymeric materials for many applications. Among these polyesters, the biodegradable and biocompatible, polylactide is very promising for many applications in both medical and industrial areas. Other biodegradable polymers such as polytrimethylene carbonate, polybutyrolactone, polyvalerolactone, and polycaprolactone can be blended or copolymerized with polylactide to fine tune the properties to fit the needs for their applications. The properties of these polymers and copolymers depend upon the tacticity of the polymers which can be directly controlled by the catalysts used for polymer production. Therefore, it has been of great interest to develop new selective catalytic systems for the ring-opening polymerization of lactide and other cyclic monomers. This dissertation focuses on developing new zinc and aluminum complexes and studying their selectivity and reactivity of these complexes for the ring-opening polymerization of lactide and other cyclic monomers, i.e. trimethylene carbonate, beta-butyrolactone, delta-valerolactone, and epsilon-caprolactone. Herein, aspects of the ring-opening polymerization of lactide and other cyclic monomers utilizing novel zinc and aluminum complexes will be discussed in detail. In the process for the ring-opening polymerization of lactide, chiral zinc half-salen complexes derived from natural amino acids have shown to be very active catalysts for producing polymers with high molecular weight and narrow polydispersities at ambient temperature. The chiral zinc complexes were found to catalyze rac-lactide to heterotactic polylactides with Pr values ranging from 0.68-0.89, depending on the catalyst and reaction temperature employed during the polymerization process. The reactivities of the various catalysts were greatly affected by substituents on the Schiff base ligands, with sterically bulky substituents being rate-enhancing. Furthermore, a series of both chiral and achiral aluminium half-salen complexes have been synthesized and characterized. These aluminum complexes all showed moderate selectivity to the ring-opening polymerization of rac-lactide to produce isotactic polylactide with Pm value up to 0.82 in toluene at 70 degrees C. Moreover, some of the studied aluminum complexes displayed epimerization of rac-lactide to meso-lactide during the polymerization process. Kinetic studies for the ring-opening polymerization of lactide utilizing these zinc and aluminum complexes are included in this dissertation. Along with these studies, the copolymerization of lactide with epsilon-caprolactone and delta-valerolactone will also be presented.
Book Synopsis Early Transition Metal Catalyzed Synthesis of Complex Polymer Architectures by : Gobinda Saha
Download or read book Early Transition Metal Catalyzed Synthesis of Complex Polymer Architectures written by Gobinda Saha and published by . This book was released on 2007 with total page 231 pages. Available in PDF, EPUB and Kindle. Book excerpt: These advances provide powerful new synthetic tools for polymer science on the way of bridging radical, ring opening and coordination polymerizations. Their implementation will converge in the controlled synthesis of monodisperse polymer structures with complex new architectures and unusual topologies and compositions based on a wide, previously inaccessible selection of monomers and therefore leading to new material properties.
Book Synopsis Structural and Kinetic Studies of the Ring Opening Polymerization of Lactides and Ε-caprolactone by Enzimidazolylmethyl)amine ZN(II) and Cu(II) Complexes by : Nelson Worlanyo Attandoh
Download or read book Structural and Kinetic Studies of the Ring Opening Polymerization of Lactides and Ε-caprolactone by Enzimidazolylmethyl)amine ZN(II) and Cu(II) Complexes written by Nelson Worlanyo Attandoh and published by . This book was released on 2014 with total page 222 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Syntheses and Characterizations of Monomeric Amidinate Tin(II) Complexes for Ring-opening Polymerization of Cyclic Esters by : Chatyapha Pongchan-o
Download or read book Syntheses and Characterizations of Monomeric Amidinate Tin(II) Complexes for Ring-opening Polymerization of Cyclic Esters written by Chatyapha Pongchan-o and published by . This book was released on 2009 with total page 166 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Synthesis, Characterization and Oxidation of New Divalent Lanthanide Bis(phenolate) Complexes and Their Applications in the Ring Opening Polymerization of Cyclic Esters by : Divine Timah Dugah
Download or read book Synthesis, Characterization and Oxidation of New Divalent Lanthanide Bis(phenolate) Complexes and Their Applications in the Ring Opening Polymerization of Cyclic Esters written by Divine Timah Dugah and published by . This book was released on 2009 with total page 272 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Synthesis and Characterization of Dimethylbismuth and -indium Phenoxy-imine Complexes as Potential Catalysts for the Ring Opening Polymerization of Cyclic Esters by : Kathleen Morrison
Download or read book Synthesis and Characterization of Dimethylbismuth and -indium Phenoxy-imine Complexes as Potential Catalysts for the Ring Opening Polymerization of Cyclic Esters written by Kathleen Morrison and published by . This book was released on 2019 with total page 156 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis N-heterocyclic Carbene Mediated Zwitterionic Polymerization for Cyclic Polymers by : Eun Ji Shin
Download or read book N-heterocyclic Carbene Mediated Zwitterionic Polymerization for Cyclic Polymers written by Eun Ji Shin and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Zwitterionic polymerization involves a propagating species with both positively and negatively charged groups. Previous investigations on zwitterionic polymerization concern alternating copolymerization of nucleophilic and electrophilic monomers and polymerization of isolated stable zwitterionic monomers. More recently, the ring-opening polymerization of cyclic monomers using nucleophilic initiators have been studied. Specifically, the zwitterionic polymerization of cyclic esters using N-heterocyclic carbenes (NHCs) is the focus of this thesis. The N-heterocyclic carbene mediated zwitterionic polymerization of cyclic monomers provides an expedient route to polymers of various architectures, such as cyclic polymers, cyclic gradient copolymers and linear telechelic polymers. The ring-opening polymerization of lactide initiated by NHCs generates cyclic poly(lactide)s of defined molecular weight and molecular weight distribution. Kinetic studies implicate a mechanism that involves a slow initiation step and a propagation step that is much faster than depropagation and chain termination by cyclization. Stochastic simulations and chain extension experiments showed that only a fraction of the NHC forms the active zwitterion in solution, leading to both chain extension of the zwitterions and re-initiation of the NHC upon addition of the second batch of monomer. These results prompted investigation of a more efficient way to prepare cyclic block copolymers. The difference in reactivity of NHCs towards different monomers was exploited to synthesize cyclic block copolymers of valerolactone (VL) and caprolactone (CL). The faster ring-opening of VL relative to CL resulted in a gradient cyclic copolymer comprised of VL-rich sequences that transition to CL-rich sequences in a cyclic macromolecule, instead of a cyclic diblock copolymer. This work not only provides a simple batch copolymerization protocol to produce cyclic gradient copolymers, but also demonstrates the marked difference in reactivity of the NHCs compared to metal catalysts, which produce random copolymers. Stereocomplexation behavior has been observed in blends of linear poly(L-lactide) and linear poly(D-lactide). The influence of topology on the formation of stereocomplex was investigated using blends of linear and cyclic poly(lactide)s prepared by NHC mediated zwitterionic polymerization. The linear/cyclic and cyclic/cyclic blends all form stereocomplexes when annealed. Analyses of data from various characterization techniques indicate that the cyclic topology imposes constraints on the stereocomplexation formation. The purity of the cyclic polymers is always a concern in the synthesis and physical property studies. Attempts to identify and quantify the linear contamination in cyclic poly(caprolactone) samples are described. Esterification reactions targeting the hydroxyl endgroups of linear contaminants were not successful, but the macroinitiator approach where the linear contaminant in a cyclic polymer sample is used as the macroinitiator to grow polymers to identify and remove the linear contamination shows promise. A cyclic polymer more robust to post-polymerization chemistry may be needed for more thorough purity studies.
Book Synopsis Studies of the Ring-opening Polymerization of Cyclic Ethers and Esters by Coordinate Catalysis by : Diana Navarro-Llobet
Download or read book Studies of the Ring-opening Polymerization of Cyclic Ethers and Esters by Coordinate Catalysis written by Diana Navarro-Llobet and published by . This book was released on 2002 with total page 376 pages. Available in PDF, EPUB and Kindle. Book excerpt: