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Showing 1 to 20 of 56 for “"Ionomers"”.
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Structure-property relationships in novel ionomers
It is observed for the first time that telechelic ionomers based on sulfonated polyisobutylene exhibit primary and secondary SAXS peaks when the molecular weight distribution is narrow (Mw/Mn ca. 1.15). These SAXS peaks are interpreted as due to non-global lamellar or cylindrical ionic domain …
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Puncture Reversal of Polyethylene Ionomers - Mechanistic Studies
Ionomers are polymers that contain ionic groups in relatively low concentrations along the polymer backbone. These ionic groups, in the presence of oppositely charged ions, form aggregates that lead to novel physical properties of the polymer. React-A-Seal® and Surlyn® are …
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Ionic exchanges between glass ionomers and demineralised dentine
… scientifically demonstrate the ability of glass-ionomers to remineralise partly demineralised dentine in vivo and in vitro. 2. To determine the nature of the remineralisation process. 3. To determine those factors having greatest impact on the remineralisation process. Those objectives are partly …
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Structure-Property Relationships of Isoprene-Sodium Styrene Sulfonate Elastomeric Ionomers
Polymers containing less than 10 mol % of ions (ionomers) have been studied in depth for their potential in producing polymers with tailored properties for specific applications. A small molar percentage of ions can be incorporated into a polymer to drastically enhance the properties of the …
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Synthesis and characterization of well-defined methacrylic-based block ionomers
… systems and their analogous block ionomers was also carried out utilizing difunctional organolithium initiation of the hydrocarbon monomers in cyclohexane. For the polymerization of the tbma, it was found that the addition of large quantities of a polar solvent, such as THF, …
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Synthesis and Characterization of Novel Telechelic High Performance Polyester Ionomers
… on material properties. Novel branched polyester ionomers using trimellitic anhydride were also prepared. In addition to modifying the polymer compositions, PET ionomers were blended with zinc stearate to investigate the effect of plasticizer on the melt processibilty of the ionomers. FTIR …
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Structure-property behavior of elastomeric telechelic ionomers in bulk and solution
… behavior of two types of elastomeric telechelic ionomers has been investigated. Sulfonated polyisobutylene telechelic ionomers were studied in both bulk and solution. The bulk mechanical properties of carboxylated polyisoprene telechelic ionomers were also investigated. The sulfonated …
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Non-Covalent Interactions in Polymeric Materials: From Ionomers to Polymer Blends
Conventional studies of ionomers have focused on ionomers bearing monovalent carboxylate or sulfonate pendant ions. There are relatively fewer studies on ionomers containing multivalent pendant ions, such as divalent phosphonate. In this dissertation, poly(ethylene terephthalate) (PET) and …
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Influence of Sidechain Structure and Interactions on the Physical Properties of Perfluorinated Ionomers
… temperature otherwise not seen in PFSA ionomers. We utilized small-angle X-ray scattering (SAXS) studies to probe the differences in aggregate structure between the PFIA and PFSA membranes in order to uncover the morphological origin of the anomalous thermomechanical behavior in PFIA …
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Synthesis and Characterization of Branched Ionomers for Performance in Ionic Liquid – Swollen Ionic Polymer Transducers
… studies conducted with non-perfluorosulfonated ionomers concentrated on changes in chemical composition to address processability, price, ionic conductivity, and hydrated modulus of the final IPT. Also, nearly all ionic polymer transducers operated with water as the diluent until the recent …
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The Effects of Structure, Humidity and Aging on the Mechanical Properties of Polymeric Ionomers for Fuel Cell Applications
… on the mechanical behavior of Nafion® and Dais® ionomers. It was determined that the majority of the properties of these membranes were controlled by the formation and growth of the ionic clusters that were the direct result of the ionic nature of these materials. In the process of this study, …
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Structural and morphological characterization of model elastomeric ion containing polymers
… particular interest are those materials termed ionomers which contain ionic groups that are typically less than 15 mole percent. These ionic interactions provides an additional means of controlling polymer structure and properties. In the conventional ionomers, the ionic groups are placed …
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Next-generation ionomers for proton exchange membrane fuel cells From catalyst¿ionomer interactions to membrane¿electrode assembly performance and durability
L'abstract è presente nell'allegato / the abstract is in the attachment
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Synthesis and Characterization of Multicomponent Polyesters via Step-growth Polymerization
… backbone architectures on the properties of PET ionomers in detail. Three series of random and telechelic PET ionomers with equivalent molecular weights and ionic contents were synthesized using conventional melt polymerization. Solid state sodium NMR spectroscopy and melt rheological analysis …
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Comparative analysis of Polymer Electrolyte Membrane (PEM) fuel cells
Per-Fluoro-Sulphonic-Acid (PFSA) ionomers have been singled out as the preferable ionomers for making the Polymer Electrolyte Membrane Fuel Cells (PEMFC) membranes owing to their extensive intrinsic chemical stability and super sulfonic acid strength which is core to the PEMFC proton conductivity. …
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Structure-Morphology-Property Relationships in Perfluorosulfonic Acid Ionomer Dispersions, Membranes, and Thin Films to Advance Hydrogen Fuel Cell Applications
… on the morphology and properties of fuel cell ionomers. The ionomer functions as a solid electrolyte membrane on the order of microns thick and as a thin film on the order of tens of nanometers in the catalyst layer. Industrial manufacture of the membrane and catalyst layer is typically a …
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Synthesis of novel methacrylate-containing polymers by anionic polymerization
… Hydrolysis of the ester group leads to ionomers of controlled structure. These systems have properties quite different from more conventional "random" ionomers, e.g., highly extended rubbery plateau behavior and no change in Tg with ion content.
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Comparative evaluation of the compressive strength surface hardness and porosity of a selection of capsule-mixed versus hand-mixed Glass lonomer cements
Introduction: Glass ionomers are available in sets of powder and liquid constituents, which are dispensed using a scoop and dropper bottle system prior to hand-mixing by an operator. Glass ionomers are also available in capsulated form, which is mixed in a suitable mechanical mixing machine prior …
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The Effect of Nanoscale Particles and Ionomer Architecture on the Crystallization Behavior of Sulfonated Syndiotactic Polystyrene
Semicrystalline ionomers are an important class of polymers that are utilized in a wide range of applications. The particular end-use applications of these materials are determined by their chemical, physical, and thermomechanical properties which are directly related to their crystallization …
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Non-Covalent Interactions in the Design and Performance of Macromolecules for Biological Technologies
… drug delivery solutions. Poly(ether ester) ionomers composed of sulfonated isophthalate and poly(ethylene glycol) provided polymers well suited for low-temperature material extrusion additive manufacturing. Ionic interactions featured in the development of these ionomers and proved vital to …
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