Morphology of lightly carboxylated polystyrene ionomers

Tomita, Hidemi; Register, Richard A.

doi:10.1021/ma00063a024

Cited by 23 publications

(20 citation statements)

References 7 publications

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“…The change in T g as a function of ion concentration ( dT g / dc ) for the acid and metal salt SVP ionomers was ∼3.4 °C/mol %. That value is similar to the dT g / dc values that have been reported for other styrene ionomers, such as SPS (2.8–3.8),26–29 p‐carboxylated polystyrene (CPS) (3.3–3.9),22, 28 styrene–methacrylate copolymers (3.3–3.8)28–30 and styrene–acrylate copolymers (3.2–3.6) 31, 32. That result is consistent with the reports by Risen et al27 and Eisenberg et al28, 33 that the T g of styrene‐based ionomers is relatively independent of the nature of the bound anion or the mobile cation.…”

Section: Resultssupporting

confidence: 88%

“…Dynamic mechanical analysis (DMA) was carried out with a TA instrument DMA 2980 using a tensile fixture, a dry nitrogen atmosphere, a heating rate of 2 °C/min, and a fixed frequency of 1 Hz. Isothermal frequency sweeps from 0.04 to 30 Hz were also obtained at temperatures between 135 and 295 °C using a shear sandwich fixture, which is particularly suited for measurements on extremely viscous melts such as ionomers 22. All measurements were made within the linear viscoelastic region, which was determined from strain sweeps.…”

Section: Methodsmentioning

confidence: 99%

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Synthesis and characterization of poly (styrene‐co‐vinyl phosphonate) ionomers

Weiß

2004

J Polym Sci B Polym Phys

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Poly(styrene‐co‐diethyl vinylphosphonate) copolymers were synthesized by free radical copolymerization. The ester groups of the copolymers were hydrolyzed to phosphonic acid groups, and the sodium and zinc salts ionomers were obtained by neutralization. The structure and the thermal and viscoelastic properties of the copolymers and ionomers were characterized by nuclear magnetic resonance, Fourier transform infrared spectroscopy, differential scanning calorimetry, dynamic mechanical analysis, and small‐angle X‐ray scattering. The phosphonate ester lowered the glass transition temperature (Tg) of polystyrene. The free acid derivatives and metal phosphonates increased Tg and produced a rubbery plateau region in the viscoelastic properties due to the formation of a physical network. The acid and salt ionomers exhibited microphase‐separated morphologies and were thermorheologically complex. The phosphonic acid derivatives absorbed relatively little water, even for materials with ion‐exchange capacities greater than 1.0 mEq/g, and were not conductive, which made them unsuitable for application as proton exchange membranes. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 3628–3641, 2004

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Section: Resultssupporting

confidence: 88%

Section: Methodsmentioning

confidence: 99%

Synthesis and characterization of poly (styrene‐co‐vinyl phosphonate) ionomers

Weiß

2004

J Polym Sci B Polym Phys

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“…The only somewhat inconsistent aspect with respect to experimental data is that if this theory was correct, then a second glass transition would be expected in measurements made via DSC. In the vast majority of cases, one glass transition in DSC spectra is found independent of ionic content and/or neutralization level, [85,[137][138][139] although in a small number of cases two glass transition heat capacity jumps were evident [137,140,141]. In a study on sodium-neutralized SMAA, [137] it was shown that the second peak in tan delta was measurable beginning at 1% ionic content, while the second DSC transition only was measurable beginning at 8.2% ion content.…”

Section: Amorphous Polymer Regions: Greater Than Nanometer Length Scalementioning

confidence: 99%

“…For example, if the relationship between the scattering intensity of two samples is changed substantially via a change where the change in electron density difference is expected to be small, as in a switch from carboxylate to sulfonate groups both being neutralized with high atomic number cations, [85] then this change could be due to either a lower electron density of the aggregate (which presumably occurs because of entrapped organic material) or because of more isolated ionic groups. The latter can be qualitatively monitored by monitoring the thermal background scattering, [85] but still, without a model, one cannot know for sure whether a decrease in intensity is due to lower electron density aggregates, that is, entrapped organic material, or more isolated ionic groups.…”

Section: Ionomer Synthesismentioning

confidence: 99%

“…The latter can be qualitatively monitored by monitoring the thermal background scattering, [85] but still, without a model, one cannot know for sure whether a decrease in intensity is due to lower electron density aggregates, that is, entrapped organic material, or more isolated ionic groups. For the case where the electron density of the aggregate changes substantially, for example, a change in cation, the situation becomes even more problematic.…”

Section: Ionomer Synthesismentioning

confidence: 99%

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Review and critical analysis of the morphology of random ionomers across many length scales

Grady

2008

Polymer Engineering & Sci

101

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This review presents a description of what is known about ionomer morphology. All papers on ionomer morphology are not included in this review; but all relevant questions about ionomer morphology are posed and answered as completely as possible. The review is critical; that is, reasons are given for morphologies that are deemed to be more or less likely. The review is organized along three length scales: sub-nanometer, nanometer to 10 nm, and greater than 10 nm. Within each length scale, all three phases are considered: crystalline, amorphous, and ionic aggregate. The purity of the three phases, the arrangement of atoms in the three phases, the size and shape of the three phases, and their arrangements in space relative to each other are explored in this review. A model for the shape of aggregates in ionomers that have well-ordered internal environments is presented. This model proposes that aggregates are fundamentally planar, but will ''roll up'' into tubes or other related structures in order to reduce the number of atoms at aggregate edges. This model was developed primarily based on the varied morphologies ionomers have shown in electron micrographs, but is consistent with other indirect measurements of ionomer morphology.

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Ionomers

Kim¹

2005

Kirk-Othmer Encyclopedia of Chemical Technology

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Polymers containing ions can be classified into two major families: polyelectrolytes and ionomers. For polyelectrolytes, the ion content is very high, eg, every repeat unit of the polymer has pendent ionic groups. Thus, polyelectrolytes are water soluble. Ionomers are used to define the thermoplastic polymers, which contain a small amount of ionic groups in a matrix of low dielectric constants. Characterization of ionomers is discussed. The use of scattering and X‐ray absorption studies, electron microscopic studies, atomic force microscopy is discussed as ways to determine ionic aggregates and morphology of ionomers. Glass transitions are also studied in this category. Properties of styrene ionomers, as well as polyethylene and polytetrafluroethylene ionomers and ionomer blends are detailed. External polasticizers for ionomers can be used as additives to plasticize either polar or nonpolar regions, or both, depending on the polarities of the additives and the ionomer. Important applications of ionomers include membranes, molded materials, and as fertilizer coatings.

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Morphology of lightly carboxylated polystyrene ionomers

Cited by 23 publications

References 7 publications

Synthesis and characterization of poly (styrene‐co‐vinyl phosphonate) ionomers

Synthesis and characterization of poly (styrene‐co‐vinyl phosphonate) ionomers

Review and critical analysis of the morphology of random ionomers across many length scales

Ionomers

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