Download or read book Structure Property Relationships in Polymers written by Charles E. Carraher Jr. and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 234 pages. Available in PDF, EPUB and Kindle. Book excerpt: The first concern of scientists who are interested in synthetic polymers has always been, and still is: How are they synthesized? But right after this comes the question: What have I made, and for what is it good? This leads to the important topic of the structure-property relations to which this book is devoted. Polymers are very large and very complicated systems; their character ization has to begin with the chemical composition, configuration, and con formation of the individual molecule. The first chapter is devoted to this broad objective. The immediate physical consequences, discussed in the second chapter, form the basis for the physical nature of polymers: the supermolecular interactions and arrangements of the individual macromolecules. The third chapter deals with the important question: How are these chemical and physical structures experimentally determined? The existing methods for polymer characterization are enumerated and discussed in this chapter. The following chapters go into more detail. For most applications-textiles, films, molded or extruded objects of all kinds-the mechanical and the thermal behaviors of polymers are of pre ponderant importance, followed by optical and electric properties. Chapters 4 through 9 describe how such properties are rooted in and dependent on the chemical structure. More-detailed considerations are given to certain particularly important and critical properties such as the solubility and permeability of polymeric systems. Macromolecules are not always the final goal of the chemist-they may act as intermediates, reactants, or catalysts. This topic is presented in Chapters 10 and 11.

Download or read book Polymers in Membrane Separations Structure property Relationships written by American Chemical Society. Division of Polymer Chemistry and published by . This book was released on with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Structure Property Relationships of Polymers in Membranes written by Aditi Damle-Bijani and published by LAP Lambert Academic Publishing. This book was released on 2011-03 with total page 240 pages. Available in PDF, EPUB and Kindle. Book excerpt: Asymmetric Cellulose acetate membranes were first developed and used for water desalination. Though the inventors designed membranes to be porous on surface which would separate salt from water by adsorption of pure water on the surface, the prevailing scientific community felt it was diffusion of pure water from the membrane which caused separation. Even after polyamide RO membranes became available which were derived by surface modification of polysulfone UF membranes that were well recognized for their porous nature, the solution-diffusion theories continued. We were compelled to take up this work to give additional evidence for existence of pores on the surface of all membranes those could separate solutes from solutions. We demonstrated that application of vacuum at outlet of membrane should improve the flux only if the membrane was not a continuous surface. Applying vacuum at outlet of the membrane is not same as applying that much additional pressure at the feed side. Polyamides that cannot form continuous structures were synthesized and demonstrated to produce porous desalination RO Membranes, with higher flux under vacuum.

Download or read book Polymer Membranes for Fuel Cells written by Javaid Zaidi and published by Springer Science & Business Media. This book was released on 2010-07-15 with total page 439 pages. Available in PDF, EPUB and Kindle. Book excerpt: From the late-1960’s, perfluorosulfonic acid (PFSAs) ionomers have dominated the PEM fuel cell industry as the membrane material of choice. The “gold standard’ amongst the many variations that exist today has been, and to a great extent still is, DuPont’s Nafion® family of materials. However, there is significant concern in the industry that these materials will not meet the cost, performance, and durability requirementsnecessary to drive commercialization in key market segments – es- cially automotive. Indeed, Honda has already put fuel cell vehicles in the hands of real end users that have home-grown fuel cell stack technology incorporating hydrocarbon-based ionomers. “Polymer Membranes in Fuel Cells” takes an in-depth look at the new chem- tries and membrane technologies that have been developed over the years to address the concerns associated with the materials currently in use. Unlike the PFSAs, which were originally developed for the chlor-alkali industry, the more recent hydrocarbon and composite materials have been developed to meet the specific requirements of PEM Fuel Cells. Having said this, most of the work has been based on derivatives of known polymers, such as poly(ether-ether ketones), to ensure that the critical requirement of low cost is met. More aggressive operational requi- ments have also spurred the development on new materials; for example, the need for operation at higher temperature under low relative humidity has spawned the creation of a plethora of new polymers with potential application in PEM Fuel Cells.

Download or read book Exploring the Structure property Relationships of Linear and Crosslinked Poly ethylene Oxide Polymer Membranes for Gas Separations written by Gregory K. Kline and published by . This book was released on 2018 with total page 202 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Structure property Relationships in Polymers written by E. H. Andrews and published by . This book was released on 1988 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Structure property Relationships in Polymers of 2 3 Dichlorobutadiene written by Mark Alfred Weih and published by . This book was released on 1991 with total page 732 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Membrane Fabrication written by Nidal Hilal and published by CRC Press. This book was released on 2015-03-02 with total page 740 pages. Available in PDF, EPUB and Kindle. Book excerpt: Membranes play a crucial role in ensuring the optimum use and recovery of materials in manufacturing. In the process industries, they are required for efficient production and minimization of environmental impact. They are also essential for the efficient production of clean water, a significant global issue. Membrane Fabrication brings together ex

Download or read book Synthesis and Structure property Relationships of Polymeric Membranes for Small Molecule Transport written by Haomiao Yuan and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: One key challenge for alkaline anion exchange membrane fuel cells is the lack of alkaline stable polycations. The synthesis of random, crosslinked and block copolymers based on the cobaltocenium phenylene norbornene (NPC) monomer is described. The polymers were synthesized from ring-opening metathesis polymerization (ROMP) of the NPC monomer showed excellent thermo-alkaline and thermo-oxidative stability. Random copolymers, crosslinked networks and amphiphilic diblock copolymers were prepared by copolymerizing NPC with different hydrophobic monomers: norbornene for random copolymers, dicyclopentadiene for crosslinked networks and a norbornene dibenzyl ether monomer for amphiphilic diblock copolymers. Mechanical robust membranes were prepared from all these copolymers. Polymers with different architectures exhibited different morphologies. Random copolymers showed disordered interconnected cobaltocenium domains with ion clusters present; crosslinked networks showed homogenous distribution of ions; the amphiphilic diblock copolymers showed cylindrical microphase separation with the cationic domains being the continuous phase even though they constituted the minor volume component. The morphologies of the membranes were found to have little effect on the water uptake of the membranes, but significantly influenced the ionic conductivity. The crosslinked membranes showed lower conductivity compared to the random copolymer membranes at the same composition. However, higher IECs can be achieved by crosslinking with concomitant improved mechanical integrity relative to their random copolymer analogs, ultimately allows for reaching higher ion conductivity values. For the diblock copolymer, formation of a conducting ion channel and elimination of the presence of ion clusters allowed for significantly higher ionic conductivity than the random copolymer or the crosslinked networks at the same composition. Poly(vinyl acetate)-b-polybutadiene-b-poly(vinyl acetate) triblock copolymer was synthesized for water/alcohol pervaporation separation membrane. A difunctional chain transfer agent (dCTA) with both reversible addition - fragmentation chain-transfer (RAFT) and ROMP functionality was synthesized. The triblock copolymers were obtained by synthesizing narrow-dispersed poly(vinyl acetate) by RAFT and subsequently inserting a polybutadiene block by ROMP. The polymers were cast as thin membranes, and the polybutadiene was crosslinked by UV radiation for mechanical robustness. Solid state hydrolysis afforded poly(vinyl alcohol)-b-polybutadiene-b-poly(vinyl alcohol) membranes. Different compositions of the polymers resulted in different morphologies. A longer polybutadiene block or a shorter poly(vinyl alcohol) block contributed to stronger phase separation. This study invented a new methodology to construct amphiphilic triblock copolymers with well-defined morphologies.

Download or read book Structure property Relationships in Polyimide ionenes and Composites with Ionic Liquids as Gas Separation Membranes written by Grayson Patrick Dennis and published by . This book was released on 2020 with total page 218 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ionic polymers have capabilities to shape the pathway to new membranes and polymer systems that did not exist before. The imidazolium moiety has shown substantial abilities to integrate into a platform for ionic polymers allowing their growth and formation through imidazolium use as a building block. Addition of this component, both ionic and non-ionic, into a polymer matrix has been developed, but the creation of highly tunable, modular polymer structure that contains imidazolium has the potential to surpass previous iterations of ionic compounds and materials in gas separation. After developing a tailorable approach to high performance ionic polymers, we have formed ionic polyimides and polyamides that have been used for various applications such as gas separation, coatings, and films. The ionic polyimides and polyamides which were formed have the potential to be used as CO2/light gas membranes.The hardest factor to overcome within membrane separation is the flux-selectivity tradeoff which describes the upper limits of permeability, gases ability to flow through a membrane, and selectivity, one gas's ability over another to permeate. With the addition of these ionic units into the backbone and as "free"-ILs within the polymer matrix, the permeabilities of these materials can be greatly increased. Through systematic design and study of materials, the structure-property relationship of these newly developed ionic polymers can be determined and applied to further the understanding of these unique polymer systems.

Download or read book Processing Structure Property Relationships in Oriented Polymers written by Zhiyong Xia and published by . This book was released on 2001 with total page 378 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Structure property Relationships of ROMP Polymers written by Marlene Elaine Hontz and published by . This book was released on 2000 with total page 428 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Water and Salt Transport Structure property Relationships in Polymer Membranes for Desalination and Power Generation Applications written by Geoffrey Matthew Geise and published by . This book was released on 2012 with total page 768 pages. Available in PDF, EPUB and Kindle. Book excerpt: Providing sustainable supplies of water and energy is a critical global challenge. Polymer membranes dominate desalination and could be crucial to power generation applications, which include reverse osmosis (RO), nanofiltration (NF), forward osmosis (FO), pressure-retarded osmosis (PRO), electrodialysis (ED), membrane capacitive deionization (CDI), and reverse electrodialysis (RED). Improved membranes with tailored water and salt transport properties are required to extend and optimize these technologies. Water and salt transport structure/property relationships provide the fundamental framework for optimizing polymer materials for membrane applications. The water and salt transport and free volume properties of a series of sulfonated styrenic pentablock copolymers were characterized. The polymers' water uptake and water permeability increase with degree of sulfonation, and the block molecular weights could be used to tune water uptake, permeability, and selectivity properties. The presence of fixed charge groups, i.e., sulfonate groups, on the polymer backbone influence the material's salt transport properties. Specifically, the salt permeability increases strongly with increasing salt concentration, and this increase is a result of increases in both salt sorption and diffusivity with salt concentration. The data for the sulfonated polymers, including a sulfonated polysulfone random copolymer, are compared to those for an uncharged polymer to determine the influence of polymer charge on salt transport properties. The sulfonated styrenic pentablock copolymer permeability data are compared to literature data using the water permeability and water/salt selectivity tradeoff relationship. Fundamental transport property comparisons can be made using this relationship. The effect of osmotic de-swelling on the polymers and the transport properties of composite membranes made from sulfonated styrenic pentablock copolymers are also discussed. The sulfonated styrenic pentablock copolymers were exposed to multi-valent ions to determine their effect on the polymer's salt transport properties. Magnesium chloride permeability depends less on upstream salt concentration than sodium chloride permeability, presumably due to stronger association between the sulfonate groups and magnesium compared to sodium ions. Triethylaluminum was used to neutralize the polymer's sulfonic acid functionality and presumably cross-link the polymer. The mechanical, transport, and free volume properties of these aluminum neutralized polymers were studied.

Download or read book Structure property Relationships in Polymers and Fibres written by Dharmendra Singh Varma and published by . This book was released on 1985 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Polymeric Foams Structure Property Performance written by Bernard Obi and published by William Andrew. This book was released on 2017-12-07 with total page 412 pages. Available in PDF, EPUB and Kindle. Book excerpt: Polymeric Foams Structure–Property–Performance: A Design Guide is a response to the design challenges faced by engineers in a growing market with evolving standards, new regulations, and an ever-increasing variety of application types for polymeric foam. Bernard Obi, an author with wide experience in testing, characterizing, and applying polymer foams, approaches this emerging complexity with a practical design methodology that focuses on understanding the relationship between structure–properties of polymeric foams and their performance attributes. The book not only introduces the fundamentals of polymer and foam science and engineering, but also goes more in-depth, covering foam processing, properties, and uses for a variety of applications. By connecting the diverse technologies of polymer science to those from foam science, and by linking both micro- and macrostructure–property relationships to key performance attributes, the book gives engineers the information required to solve pressing design problems involving the use of polymeric foams and to optimize foam performance. With a focus on applications in the automotive and transportation industries, as well as uses of foams in structural composites for lightweight applications, the author provides numerous case studies and design examples of real-life industrial problems from various industries and their solutions. Provides the science and engineering fundamentals relevant for solving polymer foam application problems Offers an exceptionally practical methodology to tackle the increasing complexity of real-world design challenges faced by engineers working with foams Discusses numerous case studies and design examples, with a focus on automotive and transportation Utilizes a practical design methodology focused on understanding the relationship between structure-properties of polymeric foams and their performance attributes

Download or read book Structural Science of Crystalline Polymers written by Kohji Tashiro and published by Springer Nature. This book was released on with total page 724 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book An Investigation of Structure property Relationships in Several Categories of Proton Exchange Membranes written by Marianne Phelan Rodgers and published by . This book was released on 2007 with total page 394 pages. Available in PDF, EPUB and Kindle. Book excerpt: The chemical and structural features of proton exchange membranes (PEMs) are related to their fuel cell relevant properties. The objective of this work is to understand structure-property relationships in PEMs through the fabrication and characterization of several classes of membranes. Incorporation of linear and angled monomers into the main chain of a polyimide permitted investigation of the effect of kinked versus linear polymers on membrane properties. The conductivity of angled sulfonated polyimide membranes is greater than those prepared from linear polymers, but water uptakes are lower. These differences are attributed to increased entanglements of angled polymers, which limit the degree of swelling and lead to increased proton concentration. Polyelectrolytes were incorporated into reinforcing materials to study the effect of incorporating and confining polyelectrolytes in the pores of reinforcing materials. The employment of reinforcing materials reduces conductivity, mobility, and permeance due to decreased ionomer content and connectivity of the ionomer. However, membranes are stronger and thinner, which compensates for these losses in terms of lower resistance and increased dimensional stability. Incorporating zirconium hydrogen phosphate (ZrP) and silicon dioxide (SiO2) into Nafion℗ membranes permitted investigation of their effect on membrane properties. Data for Nafion℗/ZrP membranes support the theory that ZrP disrupts cohesive forces in Nafion℗, causing it to absorb more water. The increased water content of the membranes does not result in increased conductivity because there is a concurrent decrease in proton concentration and mobility due to poorly conducting ZrP disrupting the conduction pathway and increased water content diluting protons and separating proton conduction sites. The decreasing density of the Nafion℗/SiO2 composite membranes with increasing SiO2 content and the increased dimensional stability of the membranes increasing compared to unmodified Nafion℗ support the theory that a rigid scaffolding forms. Due to formation of void space that increases with increasing SiO2 content, water content increases, thus diluting the protons in the membrane, leading to lower conductivity. These structure-property relationships may be relevant to other membrane systems and should be considered when designing alternative systems for proton exchange membranes.