Synthesis and Characterization of Ionically Crosslinked Networks

Synthesis and Characterization of Ionically Crosslinked Networks
Author: Qinyuan Chai
Publisher:
Total Pages: 77
Release: 2013
Genre: Chemical bonds
ISBN:

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The overall goal of this thesis was to investigate the synthesis and characterization of elastomeric polymer networks crosslinked by ion-pairs. To generate these networks, cationic polyacrylate ionomers with styrene sulfonate counter-ions were synthesized. These polymers were used to generate ionically crosslinked networks by copolymerization of the pedant vinyl ionomers with acrylate monomer. These ionically crosslinked elastomers swelled in organic solvent like covalently crosslinked elastomers, but could be dissolved and re-gelled by dissociating and re-associating the ionic bonds by double ion-exchange reactions under acidic and basic conditions. Uniaxial tensile testing and oscillatory shear rheology were used to characterize the mechanical properties of the materials and compared to covalently crosslinked control samples. In contrast to the covalently crosslinked polymers, the ionically crosslinked samples showed strong property dependence on temperature and level of strain. At room temperature, the ionically crosslinked polymer had similar properties with a covalently crosslinked elastomer. As the temperature was increased above 100°C, the fluid-like property became more and more obvious due to the rearrangement of the ionic bonds. In addition, under load the ionically crosslinked polymer also exhibited flow. This mechano-chemical response of the materials to reconfigure the network under thermo-mechanical load should provide opportunities for developing new processable and self-healing elastomers using ionic interactions.

Synthesis and Characterization of Ionically Cross-linked Networks Through the Use of Ion-pair Comonomers

Synthesis and Characterization of Ionically Cross-linked Networks Through the Use of Ion-pair Comonomers
Author: Guodong Deng
Publisher:
Total Pages: 0
Release: 2018
Genre: Acrylates
ISBN:

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Structurally dynamic polymer networks, which can break and reform under external stimuli (e.g. heat, mechanical stress, light, etc.) have emerged as a useful approach to fabricate stimuli-responsive polymers (SRPs). One general route to introduce dynamic bonds is through non-covalent supramolecular interactions. Ion-pairing, is another potential non-covalent dynamic bond distinct from other interactions like hydrogen bonding and metal-ligand interactions. In this study, we demonstrate a new route to prepare structurally dynamic polymer networks by direct copolymerization of organic ion-pair comonomers (IPCs) with n-butyl acrylate (BA). A series of these copolymers were prepared and their results of rheological, mechanical, thermal and morphological behaviors will be comprehensively studied to understand the structure-property relationships. Firstly, a phosphonium-based IPC was synthesized and copolymerized with BA to prepare polyampholyte ionomers. Evidence of microphase separation of the ion-pairs to produce vitrified ion-rich domains acting as physical cross-links was found in polyampholyte ionomers by rheological and atomic force microscopy measurements. Comparison to analogous cationic and anionic ionomers with pendant counter-ions demonstrated the strong impact of direct ion-pair cross-linking on the material's viscoelastic properties. Characterization of the corresponding polyelectrolytes showed a ca. 125 oC increase in the glass transition temperature (Tg) from the cationic to the polyampholytic polyelectrolyte. This elevated Tg allowed the vitrification of the ion-rich domains at ambient temperatures in the polyampholyte networks over a range of ion-pair concentrations. An increase in molecular weight could lead to highly entangled samples, which displayed an improved mechanical properties. Secondly, the copolymers of the ion-pair co-monomer and cationic monomer were found to effectively plasticize the synthesized polyampholytic polyelectrolyte and tune their Tg. This plasticizing effect could also be applied to the polyampholyte ionomers through the copolymerization of BA and ionic monomers blends. In this way, the Tg of vitrified ion-rich domains in polyampholyte ionomers can be approximately predicted with IPC concentration, which opens up the toolbox for designing SPRs with varying transition temperature. Thirdly, an analogous ammonium-based IPC was also synthesized and used to prepare polyampholyte ionomers. Comparison to analogous phosphonium-based polyampholyte ionomers demonstrated a stronger ion-pair interaction and weaker thermal stability in ammonium/sulfonate than phosphonium/sulfonate. This novel IPC can expand the IPCs' library and fine tune viscoelastic behavior of polyampholyte ionomers systems with less expensive starting materials.

Polymer Gels

Polymer Gels
Author: Vijay Kumar Thakur
Publisher: Springer
Total Pages: 412
Release: 2018-08-07
Genre: Technology & Engineering
ISBN: 9811060835

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This book addresses a range of synthesis and characterization techniques that are critical for tailoring and broadening the various aspects of polymer gels, as well as the numerous advantages that polymer gel-based materials offer. It presents a comprehensive collection of chapters on the recent advances and developments in the science and fundamentals of both synthetic and natural polymer-based gels. Topics covered include: synthesis and structure of physically/chemically cross-linked polymer-gels/polymeric nanogels; gel formation through non-covalent cross-linking; molecular design and characterization; polysaccharide-based polymer gels: synthesis, characterization, and properties; modified polysaccharide gels: silica-based polymeric gels as platforms for the delivery of pharmaceuticals; gel-based approaches in genomic and proteomic sciences; emulgels in drug delivery; and organogels. The book provides a cutting-edge resource for researchers and scientists working in various fields involving polymers, biomaterials, bio-nanotechnology and functional materials.

Handbook of Polymer Synthesis, Characterization, and Processing

Handbook of Polymer Synthesis, Characterization, and Processing
Author: Enrique Saldivar-Guerra
Publisher: John Wiley & Sons
Total Pages: 660
Release: 2013-02-28
Genre: Technology & Engineering
ISBN: 1118480775

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Covering a broad range of polymer science topics, Handbook of Polymer Synthesis, Characterization, and Processing provides polymer industry professionals and researchers in polymer science and technology with a single, comprehensive handbook summarizing all aspects involved in the polymer production chain. The handbook focuses on industrially important polymers, analytical techniques, and formulation methods, with chapters covering step-growth, radical, and co-polymerization, crosslinking and grafting, reaction engineering, advanced technology applications, including conjugated, dendritic, and nanomaterial polymers and emulsions, and characterization methods, including spectroscopy, light scattering, and microscopy.

Micro- and Nano-Structured Interpenetrating Polymer Networks

Micro- and Nano-Structured Interpenetrating Polymer Networks
Author: Sabu Thomas
Publisher: John Wiley & Sons
Total Pages: 424
Release: 2016-03-08
Genre: Technology & Engineering
ISBN: 1119138965

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This book examines the current state of the art, new challenges, opportunities, and applications of IPNs. With contributions from experts across the globe, this survey is an outstanding resource reference for anyone involved in the field of polymer materials design for advanced technologies. • Comprehensively summarizes many of the recent technical research accomplishments in the area of micro and nanostructured Interpenetrating Polymer Networks • Discusses various aspects of synthesis, characterization, structure, morphology, modelling, properties, and applications of IPNs • Describes how nano-structured IPNs correlate their multiscale structure to their properties and morphologies • Serves as a one-stop reference resource for important research accomplishments in the area of IPNs and nano-structured polymer systems • Includes chapters from leading researchers in the IPN field from industry, academy, government and private research institutions

Rheological Methods in Food Process Engineering

Rheological Methods in Food Process Engineering
Author: James Freeman Steffe
Publisher: Freeman Press
Total Pages: 430
Release: 1996
Genre: Business & Economics
ISBN: 0963203614

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Introduction to rheology. Tube viscometry. Rotational viscometry. Extensional flow. Viscoelasticity.

Characterization of Nanoencapsulated Food Ingredients

Characterization of Nanoencapsulated Food Ingredients
Author:
Publisher: Academic Press
Total Pages: 698
Release: 2020-03-07
Genre: Technology & Engineering
ISBN: 0128156686

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Characterization of Nanoencapsulated Food Ingredients, Volume Four in the Nanoencapsulation in the Food Industry series, introduces some of the common instrumental analysis and characterization methods for the evaluation of nanocarriers and nanoencapsulated ingredients in terms of their morphology, size distribution, surface charge and composition, appearance, physicochemical and rheological properties, and antioxidant activity. Divided in five sections, the book covers the qualitative and quantitative properties of nanoencapsulated food ingredients by different characterization techniques, besides correlating nanocarrier behavior to their physicochemical and functional properties. Authored by a team of global experts in the fields of nano- and microencapsulation of food, nutraceutical, and pharmaceutical ingredients, this title is of great value to those engaged in the various fields of nanoencapsulation and nanodelivery systems. Shows how different properties of nanoencapsulated food ingredients can be analyzed Presents the mechanism of each characterization technique Investigates how the analytical results can be understood with nanoencapsulated ingredients

Preparation, Characterization and Utilization of Electrodes Coated with Polymeric Networks Formed by Gamma Radiation Crosslinking

Preparation, Characterization and Utilization of Electrodes Coated with Polymeric Networks Formed by Gamma Radiation Crosslinking
Author: William R. Heineman
Publisher:
Total Pages: 37
Release: 1987
Genre:
ISBN:

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The preparation, characterization and application of electrodes with specific chemical properties that are imparted by surface modification with polymer networks are the long-range goals of this research. Networks that are formed by crosslinking with gamma radiation have been evaluated with respect to swelling in aqueous solution, retention of polymer in the network, permeability, and the effect of radiation dosage on all of these properties through its control of crosslinking. Ionic water-soluble polymers such as polyDIALLYL DIMETHYL AMMONIUM CHOLRIDE, poly VINYLBENZYL TRIMETHYL AMMONIUM CHLORIDE, ploySTYRENE SULFONIC ACID, SODIUM SALT and polyACRYLIC ACID, which would ordinarily dissolve from the electrode surface in aqueous solution unless crosslinked into a network, and several neutral polymers such as polyACRLYONITRILE, polyETHYLENEIMINE, polyDIMETHYLSILOXANE and poly VINYL ALCOHOL have been investigated. The covalent attachment of organic and inorganic redox mediators and enzymes to networks by gamma irradiation of a mixture of polymer and the agent have been investigated. Network-coated electrodes with the appropriate properties are being developed for specific applications that required a stable, easily fabricated, fouling-resistant, rapidly responding, sensitive, and selective electrode.

Advanced Polyimide Materials

Advanced Polyimide Materials
Author: Shi-Yong Yang
Publisher: Elsevier
Total Pages: 499
Release: 2018-04-20
Genre: Technology & Engineering
ISBN: 0128126418

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Advanced Polyimide Materials: Synthesis, Characterization and Applications summarizes and reviews recent research and developments on several key PI materials. A wide array of PI materials are included, including high performance PI films for microelectronic fabrication and packaging, display and space applications, fiber-reinforced PI composites for structural applications in aerospace and aviation industries, and PI photoresists for integrated circuit packaging. The chemical features of PI are also described, including semi-alicyclic PIs, fluorinated PIs, phosphorous-containing PIs, silicon-containing PIs and other new varieties, providing a comprehensive overview on PI materials while also summarizing the latest research. The book serves as a valuable reference book for engineers and students working on polymer materials, microelectronics manufacturing and packaging in industries such as aerospace and aviation. Reviews the latest research, development and future prospective of polyimides Describes the progress made in the research on polyimide materials, including polyimide films, matrices for carbon fiber composites, coatings for microelectronics and display devices, forms and fibers Presents a highly organized work that is composed of different sections that are easily compared

Functional Nanocomposite Hydrogels

Functional Nanocomposite Hydrogels
Author: Anuj Kumar
Publisher: Elsevier
Total Pages: 617
Release: 2023-06-22
Genre: Medical
ISBN: 0323996396

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Functional Nanocomposite Hydrogels: Synthesis, Characterization, and Biomedical Applications reviews how the unique properties of nanoscale composite materials make them ideal candidates for use in biomedical hydrogels. The book covers a range of key nanocomposite materials for use in biomedical hydrogels, including graphene quantum dot, cellulose and collagen nanocomposites. A wide selection of biomedical applications for functional nanocomposite hydrogels is explored, from drug delivery and cancer therapy, to wound healing and bioimaging. This is a key reference for those working in the fields of biomaterials, nanotechnology, pharmacology, biomedical engineering, and anyone with a particular interest in composites and hydrogels. To improve the properties of conventional hydrogels, nanoparticles or nanostructures are incorporated into the hydrogel networks, forming a composite hydrogel with specialized functional properties which are tailored to a specific biomedical application. Reviews the benefits and challenges of nanocomposites as novel materials in biomedical hydrogels, providing the reader with a wider range of choice and improved options for hydrogel development Describes the synthesis and characterization of nanocomposite hydrogels, offering end-to-end analysis of the process Details the range of applications in biomedicine for nanocomposite hydrogels, including biosensing, antimicrobics and drug delivery