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.

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:

Download or read book Ring opening Polymerization written by Kenneth John Ivin and published by . This book was released on 1984 with total page 544 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Selective Organocatalytic Ring opening Polymerization of Cyclic Esters and Carbonates written by Caleb Nathaniel Jadrich and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Chapter 1 introduces polyesters as sustainable alternatives to traditional petroleum-based plastics, including biorenewable sourcing, degradability, and methods of synthesis and manufacture. It specifically highlights the advantages of polyesters produced by ring-opening polymerization (ROP) and manufactured by additive manufacturing technologies. Chapter 2 describes a catalyst system comprising a hindered base and a primary alcohol initiator which can be utilized for controlled, ultrafast polymerization cyclic monomers when utilized in conjunction with a continuous flow reactor. It highlights the advantages of continuous flow reactors for improving reaction control. Chapter 3 describes a fast, selective organocatalyst for the ROP of cyclic esters and carbonates that functions by simultaneous activation through hydrogen bonding while the monomer is activated by the bound counter ion. Chapter 4 discusses recent developments in the synthesis of polyester resins by ROP, and the mechanical properties of parts generated from them using continuous liquid interface production (CLIP) additive manufacturing. Appendix 1, Appendix 2, and Appendix 3 serve as supplementary information about the materials, methods, and results from Chapter 2, Chapter 3, and Chapter 4, respectively.

Download or read book Metallic Catalysts for Ring Opening Polymerization of Cyclic Esters and Related Compounds written by Isha Jain and published by Mohammed Abdul Sattar. This book was released on 2024-03-24 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Polymers are extremely useful materials that have become an irreplaceable component of modern life. Synthetic polymers exhibit a multitude of applications in medicine, agriculture, packaging, and textile industries. Synthetic polymers like poly(ethylene) (PE), poly(propylene) (PP) and poly(styrene) (PS), poly (vinyl chloride) (PVC), poly (ethylene terephthalate) (PET), poly (urethane) (PU), etc. are obtained from petroleum-based sources and cover 90% of total synthesized plastics. A recent report revealed that global plastic production has increased from 270 million metric tons in the year 2010 to 370 million metric tons in 2020. The annual production volumes are expected to increase further in the coming years, approximately 590 million metric tons by the year 2050. Due to the non-biodegradability of synthetic polymers, each year post-consumer plastics generate huge waste which is diverted to landfills or the natural environment. These are pervasive and persistent in the environment and cause ecological and health risks at a global scale. In the recent past, a lot of scientific research efforts are devoted to replace non- biodegradable petroleum-based resources with renewable biodegradable polymers, and the polymer industry has witnessed remarkable progress. The bioplastics are rapidly gaining commercial interest globally, which is indicated by the up-trend in the market size which rose up to USD 13.11 billion in 2022 and expected to hit USD 46.1 billion by 2030. Estimated annual growth rate (CAGR) is expected to retain a value of 17.02% from 2022 to 2030. Among the various classes of biodegradable polymers, aliphatic polyesters are of leading interest since hydrolytic or enzymatic cleavage yields hydroxy carboxylic acids which can be metabolized to produce water and carbon dioxide as degradation products without formation of any toxic side product. For example, PLA (polylactide) is an attractive renewable alternative to the petro-based polymers, it decomposes in biological environments or in the presence of microorganisms to H20, C02 and humus to soil.

Download or read book H bonding Catalyst Systems for the Ring opening Polymerization of Cyclic Esters and Carbonates written by Timothy J. Bannin and published by . This book was released on 2018 with total page 370 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Catalytic Polymerization of Cycloolefins written by V. Dragutan and published by Elsevier. This book was released on 2000-06-26 with total page 1293 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book covers the most important topics concerning cationic Ziegler-Natta and ring-opening metathesis polymerization of cycloolefins. The work describes the major pathways that cycloolefins can follow under the action of specific catalytic systems, essentially vinyl and ring-opening polymerization, both reaction types allowing the manufacture of distinct products with wide applicability in modern technologies. The comprehensive data available on this subject are logically and systematically selected and reviewed throughout 18 chapters, according to the basic catalytic processes involved, types of monomers and catalysts employed, reaction conditions and application fields. The modern trends in design of chiral metallocene catalysts, well-defined living metathesis catalysts, catalysts tolerant toward functionalities and water systems are highlighted. The book discusses in detail the relevant aspects of these processes including reaction thermodynamics, kinetics, mechanisms and stereochemistry and correlates the structure of produced polymers with their chemical and physical-mechanical properties. Related important topics include Ziegler-Natta polymerization of olefins and dienes, atom transfer radical polymerization of vinyl compounds, metathesis of olefins and acetylenes, acyclic diene metathesis reaction, carbonyl olefination reaction, metathesis polymerization of acetylenes, metathesis degradation of polymers and ring-opening polymerization of heterocycles. Special emphasis is laid upon the manufacture of commerical products, new polymers and copolymers of potential interest for industry and design and synthesis of speciality polymers with particular structures and architectures and desired properties. The book critically evaluates the most recent achievements reported in this field and outlines the modern trends on the research and application of the catalytic processes for cycloolefin polymerization. For the first time, comprehensive information about the published data on the subject up to now is provided for both academic and industrial researchers working in the areas of polymer chemistry, organic and organometallic chemistry, surface science and catalysis, petrochemistry and chemical engineering. This stimulating book offers an enlightening introduction and a quick documentation on the subject as well as a solid background in this field. Moreover, the work offers a wealth of useful information for specialists applying polymers in various scientific and industrial areas.

Download or read book Handbook of Telechelic Polyesters Polycarbonates and Polyethers written by Sophie M. Guillaume and published by CRC Press. This book was released on 2017-03-31 with total page 310 pages. Available in PDF, EPUB and Kindle. Book excerpt: Telechelic polymers have garnered a great deal of scientific interest due to their reactive chain-end functions. This comprehensive book compiles and details the basic principles of and cutting-edge research in telechelic polyesters, polycarbonates, and polyethers, ranging from synthesis to applications. It discusses general strategies toward telechelic polymers, centered on the fundamental aspects of polycondensation reactions, of cationic, anionic, coordination-insertion, and activated monomer mechanisms of the metal-, enzyme-, or otherwise organocatalyzed ring-opening polymerization of cyclic monomers, and of postpolymerization chemical modification methods of polymer precursors. All main classes of polymers are covered separately, comprising polyhydroxyalkanoates, poly(ε-caprolactone)s, poly(lactic acid)s, polylactides, polycarobnates, and polyethers, including synthetic approaches as well as some illustrative, up-to-date examples and uses. The book also addresses applications of hydroxyl, thiol, amino, or acrylate/methacrylate end-capped polymers as starting materials for the preparation of diverse polymer architectures ranging from block, graft, and star-shaped polymers and micelles to precursors for ATRP macroinitiators, polyurethane copolymers, shape-memory polymers, or nanosized drug delivery systems. The book will appeal to advanced undergraduate- and graduate-level students of polymer science; researchers in macromolecular science, especially those with an interest in functional and reactive polymers; and polymer chemists in academia and industry.

Download or read book Organic Catalysis for Polymerisation written by Andrew Dove and published by Royal Society of Chemistry. This book was released on 2018-11-15 with total page 668 pages. Available in PDF, EPUB and Kindle. Book excerpt: In recent years polymerisation using organocatalysts has become an appealing alternative to more traditional metal-based catalysts. Conferring numerous advantages including low cost and ease of use, as well as the ability to precisely control the synthesis of advanced polymer structures, organocatalysts are increasingly used in polymer synthesis. Organic Catalysis for Polymerisation provides a holistic overview of the field, covering all process in the polymer synthesis pathway that are catalysed by organic catalysts. Sub-divided into two key sections for ease of use, the first focuses on recent developments in catalysis and the applications of catalysts to the full range of polymerisations that they have been utilised in; the second concerning monomers, arranges the field by monomer type and polymerisation mechanism. The book will therefore, provide a complimentary view of the field, providing both an overview of state-of-the-art catalyst development and also the best methodologies available to create specific polymer types. Edited by leading figures in the field and featuring contributions from researchers across the globe, this title will serve as an excellent reference for postgraduate students and researchers in both academia and industry interested in polymer chemistry, organic chemistry, catalysis and materials science.

Download or read book Metal Catalyzed Carbonylative Polymerizations of Cyclic Ethers written by Yessi Permana and published by LAP Lambert Academic Publishing. This book was released on 2015-08-24 with total page 112 pages. Available in PDF, EPUB and Kindle. Book excerpt: Significant research activities have occurred in the area of polymers. Challenges to control structures and properties have attracted polymer scientists to seek better synthetic strategies than existing ones. One of the challenges is to develop a synthetic strategy towards poly(4-hydroxybutyrate) or known as well as poly( -lactone) - a polymer known to be very difficult to achieve from ring opening of its lactone monomer. This book describes possible strategies to achieve such a polymer by metal catalysis. Instead of directly ring opening the lactone, a synthetic strategy by carbonylative polymerization allows cyclic ethers to be converted into polymers with the same structures as ring opened-lactones."

Download or read book Ring opening Polymerization written by James E. McGrath and published by . This book was released on 1985 with total page 416 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Chiral Indium Catalysts for the Ring opening Polymerization of Cyclic Esters written by Dinesh Chinthaka Aluthge and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

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.

Download or read book Organocatalytic Ring opening Polymerization of Cyclic Lactones written by Pothupitiya Jinal U. and published by . This book was released on 2019 with total page 540 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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.

Download or read book The Synthesis and Characterization of Methylbismuth Dialkoxides as Potential Catalysts for the Ring opening Polymerization of Cyclic Esters written by Adam Beckett and published by . This book was released on 2017 with total page 106 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Organocatalyzed Ring Opening Polymerization and the Design of Materials for Topological Trapping written by Tyler Stukenbroeker and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Ring-opening polymerization (ROP) is a highly useful route to well-defined, high molecular weight polymers. In recent years, strongly nucleophilic neutral bases such as N-heterocyclic carbenes (NHCs) have been shown to catalyze ring opening polymerization with control over the topology of the polymer product. This mechanism has been termed Zwitterionic Ring Opening Polymerization (ZROP). Here, new catalysts and monomers have been explored for these processes. Two types of organocatalysts were developed. A recently reported superbase, cyclopropenimine, was tested for activity with a number of monomers. It was discovered that this catalyst polymerizes lactide not through ZROP, but through anionic ROP initiated by a previously unreported mechanism. It was demonstrated that cyclopropenimines deprotonate lactide to form the corresponding enolate, which serves as the initiator and endgroup for the polymerization. Additionally, an electrophilic co-catalyst for lactide polymerization based on a cationic bis(imidazolium) structure was discovered. Furthermore, a class of cyclic phosphotriesters was synthesized as a substrate for NHC-catalyzed polymerization. Mechanistic studies were consistent with the existing interpretation of ZROP. The topology of the polymer products was found to be highly impacted by slight changes in monomer structure. One of these monomers, 2-isoproxy-1,3,2-dioxophospholane 2-oxide (iPP), yielded high molecular weight cyclic products. To further interrogate the polymer architecture, a crosslinked polyacrylate network was formed in-situ with the poly(iPP). In this way cyclic macromolecules were topologically trapped, preventing their extraction by solvent washing. The gel platform used for this trapping protocol was optimized and this process was explored as a way to sort polymers based on their topology. Finally, the properties of these gels, a unique form of interpenetrating network, were studied.