Synthesis and Characterizations of Poly(organophosphazenes) PDF Download
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Author: Roger De Jaeger
Publisher: Nova Publishers
ISBN: 9781594540240
Category : Science
Languages : en
Pages : 390
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Book Description
Gleria (materials science, Padova University, Italy) and De Jaeger (chemistry, University of Sciences and Technologies, France) present the latest work in the synthesis and characterization of poly(organophosphazenes). The book opens with a general introduction on background, developments, and future perspectives, then covers the synthetic aspects of phosphazene polymers, with chapters on areas such as ambient temperature cationic condensation synthesis of polyphosphazenes and high molecular weight polyspirophosphazenes. Chapters on the characterization of phosphazene polymers in solution explore topics including thermal and mechanical properties of polyphosphazenes and electrochemical behavior of phosphazenes. Annotation : 2004 Book News, Inc., Portland, OR (booknews.com).
Author: R. H. Neilson
Publisher:
ISBN:
Category :
Languages : en
Pages : 13
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Book Description
The project involves a detailed study of the synthesis, characterization, and reactivity of silicon-nitrogen-phosphorus compounds, some of which are useful precursors to an important class of inorganic polymers known as polyphosphazenes. Our results include the successful development of a new, general, and direct method for the synthesis of such polymers including poly(dimethyl-phosphazene), (Me2PN)n. Thus, we report here the synthesis of a variety of new phosphazenes including several homopolymers, copolymers, crosslinked polymers, and transition metal containing polymers. The latter and many other new types of phosphazenes are now readily accessible by a recently discovered anion formation reaction of the polymer precursors.
Author: Roger De Jaeger
Publisher: Nova Publishers
ISBN: 9781594540240
Category : Science
Languages : en
Pages : 390
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Book Description
Gleria (materials science, Padova University, Italy) and De Jaeger (chemistry, University of Sciences and Technologies, France) present the latest work in the synthesis and characterization of poly(organophosphazenes). The book opens with a general introduction on background, developments, and future perspectives, then covers the synthetic aspects of phosphazene polymers, with chapters on areas such as ambient temperature cationic condensation synthesis of polyphosphazenes and high molecular weight polyspirophosphazenes. Chapters on the characterization of phosphazene polymers in solution explore topics including thermal and mechanical properties of polyphosphazenes and electrochemical behavior of phosphazenes. Annotation : 2004 Book News, Inc., Portland, OR (booknews.com).
Author: Roger De Jaeger
Publisher: Nova Publishers
ISBN: 9781594540257
Category : Science
Languages : en
Pages : 322
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Book Description
Gleria (National Research Council, Italy) and De Jaeger (chemistry, University of Sciences and Technologies, France) present material dedicated to the use of poly(organophosphazenes) in biology, photochemistry, and high energy radiation chemistry. Their use as hybrid materials, flame and fire retardants, blend components, ionic conductors, membranes, and catalysts is also examined. Research on cyclomatrix polyphosphazene for membrane applications, sulfonated polyphosphazene membranes for direct methanol fuel cells, and synthesis and applications of phosphazene compounds is described. Annotation : 2004 Book News, Inc., Portland, OR (booknews.com).
Author: Mario Gleria
Publisher: Nova Publishers
ISBN: 9781590334232
Category : Science
Languages : en
Pages : 1066
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Book Description
The main aim of this book is to provide a complete picture of current research on phosphazene compounds carried out around the world. The book opens with a general introduction, then moves on to cover synthetic aspects of phosphazene polymers, their characterization in solution and from the theoretical, thermal, and mechanical points of view; application aspects of poly(organophosphazenes); and the synthesis, characterization, and practical utilization of cyclophosphazenes. There is particular focus on the use of cyclophosphazenes as hydraulic fluids and additives, as cores for star polymers or dendrimers, and as starting substrates for supramolecular chemistry and nanostructured materials. The spectroscopic characterization of these compounds by NMR and Raman techniques is also discussed. Annotation : 2004 Book News, Inc., Portland, OR (booknews.com).
Author: Zhicheng Tian
Publisher:
ISBN:
Category :
Languages : en
Pages :
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Book Description
The work described in this thesis is divided into three major parts, and all of which involve the exploration of the chemistry of polyphosphazenes. The first part (chapters 2 and 3) of my research is synthesis and study polyphoshazenes for biomedical applications, including polymer drug conjugates and injectable hydrogels for drug or biomolecule delivery. The second part (chapters 4 and 5) focuses on the synthesis of several organic/inorganic hybrid polymeric structures, such as diblock, star, brush and palm tree copolymers using living cationic polymerization and atom transfer radical polymerization techniques. The last part (chapters 6 and 7) is about exploratory synthesis of new polymeric structures with fluorinated side groups or cycloaliphatic side groups, and the study of new structure property relationships.Chapter 1 is an outline of the fundamental concepts for polymeric materials, as such the history, important definitions, and some introductory material for to polymer chemistry and physics. The chemistry and applications of phopshazenes is also briefly described.Chapter 2 is a description of the design, synthesis, and characterization of development of a new class of polymer drug conjugate materials based on biodegradable polyphosphazenes and antibiotics. Poly(dichlorophosphazene), synthesized by a thermal ring opening polymerization, was reacted with up to 25 mol% of ciprofloxacin or norfloxacin and three different amino acid esters (glycine, alanine, or phenylalanine) as cosubstituents via macromolecular substitutions. Nano/microfibers of several selected polymers were prepared by an electrospinning technique. The hydrolysis rate and the antibiotic release profile can be well tuned by either the polymer compositions, or the surface area monitored by a six week in vitro hydrolysis experiment. All the polymers gave a near-neutral hydrolysis environment with the pH ranging from 5.9--6.8. In an in vitro antibacterial test against E.coli, the antibacterial activity of the hydrolysis media was maintained as long as the polymer hydrolysis continued.Chapter 3 is concerned with the development of a class of injectable and biodegradable hydrogels based on water-soluble poly(organophosphazenes) containing oligo(ethylene glycol) methyl ethers and glycine ethyl esters. The hydrogels can be obtained by mixing [alpha]-cyclodextrin aqueous solution and poly(organophosphazenes) aqueous solution in various gelation rates depending on the polymer structures and the concentrations. The rheological measurements of the supramolecular hydrogels indicate a fast gelation process and flowable character under a large stain. The hydrogel system also exhibits structure-related reversible gel-sol transition properties at a certain temperature. The formation of a channel-type inclusion complex induced gelation mechanism was studied by DSC, TGA, 13C CP/MAS NMR and X-ray diffraction techniques. In vitro bovine serum albumin release of the hydrogel system was explored and the biodegradability of poly(organophosphazenes) was studied.Chapter 4 outlines the preparation of a number of amphiphilic diblock copolymers based on poly[bis(trifluoroethoxy)phosphazene] (TFE) as the hydrophobic block and poly(dimethylaminoethylmethacrylate) (PDMAEMA) as the hydrophilic block. The TFE block was synthesized first by the controlled living cationic polymerization of a phosphoranimine, followed by replacement of all the chlorine atoms using sodium trifluoroethoxide. To allow for the growth of the PDMAEMA block, 3-azidopropyl-2-bromo-2-methylpropanoate, an atom transfer radical polymerization (ATRP) initiator, was grafted onto the endcap of the TFE block via the 'click' reaction followed by the ATRP of 2-(dimethylamino)ethyl methacrylate (DMAEMA). Once synthesized, micelles were formed by a standard method and their characteristics were examined using fluorescence techniques, dynamic light scattering, and transmission electron microscopy. The critical micelle concentrations of the diblock copolymers as determined by fluorescence techniques using pyrene as a hydrophobic probe were between 3.47 and 9.55mg/L, with the partition equilibrium constant of pyrene in these micelles ranging from 0.12x105-1.52x105. The diameters measured by dynamic light scattering were 100-142nm at 25oC with a narrow distribution, which were also confirmed by transmission electron microscopy. Chapter 5 is a report on the design and assembly of polyphosphazene materials based on the non-covalent "host--guest" interactions either at the terminus of the polymeric main-chains or the pendant side-chains. The supramolecular interaction at the main chain terminus was used to produce amphiphilic palm-tree like pseudo-block copolymers via host-guest interactions between an adamantane end-functionalized polyphosphazene and a 4-armed [beta]-cyclodextrin ([beta]-CD) initiated poly[poly(ethylene glycol) methyl ether methacylate] branched-star type polymer. The formation of micelles of the obtained amphiphiles was analyzed by fluorescence technique, dynamic light scattering, transmission electron microscopy, and atomic force microscopy. The supramolecular interactions involving polymer side-chains were achieved between polyphosphazenes with [beta]-CD pendant units and other polyphosphazene molecules with adamantyl moieties on the side-chains. These interactions worked as physical crosslinks which were responsible for the formation of a supramolecular hydrogel. The results of this work demonstrated the synthetic possibilities for these novel polymeric structures. These materials show potential for applications as smart drug delivery micro-vehicles, responsive hydrogels, and self-healing materials.Chapter 6 is an investigation of the influence of bulky fluoroalkoxy side groups on the properties of polyphosphazenes. A new series of mixed-substituent high polymeric poly(fluoroalkoxyphosphazenes) containing trifluoroethoxy and branched fluoroalkoxy side groups was synthesized and characterized by NMR and GPC methods. These polymers contained 19--29 mol% of di-branched hexafluoropropoxy groups or 4mol% of tri-branched tert-perfluorobutoxy groups, which serve as regio-irregularities to reduce the macromolecular microcrystallinity. The structure--property correlations of the polymers were then analyzed and interpreted by several techniques: specifically by the thermal behavior by DSC and TGA methods, the crystallinity by wide-angle X-ray diffraction, and the surface hydrophobicity/oleophobicity by contact angle measurements. Ultraviolet crosslinkable elastomers were prepared from the new polymers through the incorporation of 3mol% of 2-allylphenoxy and photo-irradiation. The mechanical properties and the elastomeric deformation--recovery behavior were then monitored by varying the time of ultraviolet irradiation. Side reactions detected during the synthesis of the high polymers, such as side group exchange reactions and alpha-carbon attack, were analyzed via use of a cyclic trimer model system.Chapter 7 is an outline of the exploratory synthesis of a new series of phosphazene model cyclic trimers and single- and mixed- substituent high polymers containing cyclic aliphatic rings, --CnH2n-1 (where n = 4--8). The cylco-aliphatic side group containing phosphazenes expand the structural and property boundaries of phosphazene chemistry, and suggest additional approaches for studying slow macromolecular substitution reactions and substituent exchange reactions. Polymer structure--property relationships are interpreted and correlated to glass transition temperatures, thermal decomposition temperatures, hydrophobicity, and membrane mechanical properties. Films prepared from these polymers are low cost, tough and non-adhesive. They can be used in variety of applications especially where transparency is important.
Author: Alexander K. Andrianov
Publisher:
ISBN: 9780841233614
Category : Computers
Languages : en
Pages : 272
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Book Description
A symposium titled "Polyphosphazenes in Biomedicine, Engineering & Pioneering Synthesis" was held at a recent meeting of the American Chemical Society (ACS) in August 2017 in Washington, DC. The chapters in this book provide a summary of the international contributions reported at that meeting, the purpose of which was to bring together a broad range of topics, research investigators, and representatives from industry to discuss the current status of different aspects of this field.
Author:
Publisher:
ISBN:
Category : e-Articles
Languages : en
Pages :
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Book Description
Author: Sophie Monge
Publisher: Royal Society of Chemistry
ISBN: 1849736464
Category : Science
Languages : en
Pages : 334
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Book Description
A comprehensive overview of the synthesis of different phosphorus-containing polymers and their uses in biomedical, environmental and energy applications.
Author: Harry R. Allcock
Publisher: Wiley-Interscience
ISBN: 9780471443711
Category : Technology & Engineering
Languages : en
Pages : 0
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Book Description
Polyphosphazenes are polymers containing nitrogen as part of their backbone; they are commonly used in O-rings, pipelines, and seals in oil, fuel delivery, and storage systems. New polyphosphazene derivatives have been proven biocompatible, biodegradable, and bioactive, and some of them are being investigated for possible medical applications. Harry Allcock’s Chemistry and Applications of Polyphosphazenes provides the only published compilation of material on polyphosphazenes, detailing synthetic methodologies and physical properties for each substance. Allcock explains the critical relationships between structure and properties, aiding the practicing researcher in the design of polyphosphazenes with specific applications. Professionals and students in polymer science, engineering, and industries such as rubbers and plastics will find Chemistry and Applications of Polyphosphazenes to be an invaluable text.
Author: Harry R. Allcock
Publisher:
ISBN:
Category :
Languages : en
Pages : 6
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Book Description
The objective of this work was the synthesis and evaluation of new polymers derived from the inorganic elements. Specifically, the goal was to develop new methods of synthesis for polyphosphazenes and to develop an understanding of the ways in which changes in molecular structure alter the properties of the polymers and allow improved polymers to be designed. First, a method has been developed for the synthesis of new polyphosphazenes with cyano side groups, and these have been used as precursors for the construction of organic side groups derived from the phosphazene-nitrile structure. The new polymers are expected to be useful as new films and elastomers. Second, a number of new classes of cyclo- and polyphosphazenes have been prepared that incorporate transition metals, such as iron, ruthenium, chromium, or cobalt into the organometallic side group structure. These macromolecules are hybrid polymer-metal materials, some of which combine the properties of organic polymers with those of metals. Typical of these materials are polyphosphazenes with ferrocene units as side groups. These show semiconductor properties and unusual oxidation-reduction behavior. Third, a series of small molecule linear phosphazenes have been prepared that serve as synthetic and structural models for the high polymers. (aw).
