Sizes and stabilities of multiplets and clusters in carboxylated and sulfonated styrene ionomers

Hird, B.; Eisenberg, Adi

doi:10.1021/ma00050a013

Cited by 147 publications

(212 citation statements)

References 9 publications

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“…However, ionic strength in sodium-carboxylate pairs is weaker than that in sodium-sulfonate pairs, and thus the number of ionic groups per micelle should be larger for the Sul case than for the Tol case. 10 In this case, the number of micelles should also be larger for Tol than for Sul. These two factors may thus contribute to the larger number of micelles, leading to higher ionic modulus for the MA Tol samples than for MASul.…”

Section: Dynamic Mechanical Thermal Analysis (Dmt A)mentioning

confidence: 99%

Effects of Organic Salts on Dynamic Mechanical Properties of Styrene Ionomers

Nah

Kim

et al. 1999

Polym J

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Polymers of low dielectric constants, contammg relatively small amounts of ionic comonomers, frequently show microphase-separation. 1 · 2 This is caused by ion aggregation within the relatively nonpolar matrix. It is generally accepted that ion-pairs aggregates form quadruplets, sextuplets, and higher aggregates, called multiplets. 3 Ion aggregation leads to reduction in the mobility of surrounding matrix segments. At high ion concentrations, overlap of the restricted mobility regions occurs and gives rise to larger contiguous regions, called clusters, 4 in which the material exhibits a second glass transition temperature ( Tg) higher than that of the matrix Tg.Since ionomers have nonpolar matrix regions and polar multiplets, the selective plasticization of ionomers should be possible. 2.5 A plasticizer affects selectively either multiples or a matrix phase, or both. Thus, we can choose plasticizers to achieve particular properties of ionomers.Recently, Kim eta!. 6 found that the addition of sodium dodecylbenzenesulfonate, SDBS, to sodium sulfonated polystyrene ionomers resulted in large decrease in the cluster Tg. The matrix Tg decreased only slightly. The presence of the SDBS molecules thus led to plasticization of the ionic clusters. This preferential plasticization is the result of incorporation of ionic groups of SDBS molecules into multiplets, with nonpolar alkyl chains of SDBS residing in the reduced mobility regions. Orler et al. 7 compared the plasticization effects of sodium benzenesulfonate (SBS) to those of SDBS in sulfonated polystyrene ionomers. They found that the SBS depresses the cluster Tg slightly without affecting the matrix Tg, and that decrease in the cluster Tg is less in systems plasticized with the SDBS. Tong and Bazuin 8 observed an unusual plasticization effect on the properties of poly(ethyl acrylate-co-sodium acrylate) ionomers plasticized with sodium hexadecanoate. Sodium hexadecanoate was crystalline and remained phase-separated when mixed with the ionomer, and phase-separated organic salts acted as merely filler.In the present study, we explore the effects of changing a carboxylate ionic group to a sulfonate ionic group and the effects of the amounts of organic salts. Thus, taking t To whom correspondence should be addressed.poly(styrene-co-sodium methacrylate) ionomer as the first system, comparison is made between dynamic mechanical properties of ionomers mixed with sodium ptoluate (To!) and sodium p-toluenesulfonate (Sui) salts. Then, we take poly(styrene-co-sodium styrenesulfonate) ionomer as the second system, and compare the properties of ionomers containing To! salts to those of ionomers containing Sui salts. The dependence of clustering on filler effects is addressed briefly. EXPERIMENTAL Sample PreparationTwo poly(styrene-co-methacrylic acid) samples were prepared by bulk free radical polymerization of styrene and methacrylic acid monomers. Polystyrene (MW = ca. 300000) was also prepared by bulk free radical polymerization. The sulfonation method developed by Makowski et...

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Section: Dynamic Mechanical Thermal Analysis (Dmt A)mentioning

confidence: 99%

Effects of Organic Salts on Dynamic Mechanical Properties of Styrene Ionomers

Nah

Kim

et al. 1999

Polym J

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“…It postulates that ionomers containing ionic groups linked directly to the polymer back- bone exhibit notable differences from their initial constituents as a result of strong electrostatic attractive forces (opposite to the elastic ones), the ionic groups, incorporates at random, form ion pairs. 16 These ion pairs aggregate to form quadruplets, sextuplets, and higher aggregates, collectively called multiplets. The multiplets cause a restriction of the mobility of the polymer segments adjacent to the multiplet.…”

mentioning

confidence: 99%

Proton conducting blends based on polysulfones and elastomers

Linares

Acosta

Rodríguez

2006

J of Applied Polymer Sci

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ABSTRACT:With the aim of improving the performance of conventional proton conducting membranes, systems based on two poly(arylene ether sulfone)s and two elastomers were obtained by heterogeneous sulfonation with chlorosulfonic acid. Subsequently, they were characterized, morphologically and electrically, by techniques such as infrared spectroscopy (FTIR), differential scanning calorimetry, dynamic-mechanical analysis, and complex impedance spectroscopy. From the results, it was verified that the reaction of sulfonation had taken place, as well as that these materials formed incompatible and good proton conducting blends. In addition, the storage modulus and the conductivity were subjected to a statistical design to predict the optimum composition, presenting the best mechanical and conducting proton values and as a consequence the most suitable membrane from the point of view of its application in the field of the fuel cells. Very promising results have been found especially with membranes based on binary blends constituted by thermoplastic/elastomer polymers.

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“…The theoretical model proposed by Eisenberg, Hird and Moore (EHM), 28 to explain the relationship between properties and morphology, postulates that ionomers exhibit notable differences from their initial constituents, since as a result of strong electrostatic attractive forces (opposite to the elastic ones), the ionic groups, incorporated at random, form ion pairs. 29 These ion pairs aggregate and form quadruplets, sextuplets, and higher aggregates, collectively called multiplets. The multiplets cause a restriction of the mobility of the polymer segments adjacent to the multiplet.…”

Section: Sulfonated Systemsmentioning

confidence: 99%

Effect of Sulfonation on Thermal, Mechanical, and Electrical Properties of Blends Based on Polysulfones

Linares

Benavente

2009

Polym. J.

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Different blends based on polysulfone (PSU), polyethersulfone (PES) and polyimide (PI) were prepared and characterized by Fourier transform IR spectroscopy, differential scanning calorimetry, dynamic-mechanical analysis, and microhardness. Subsequently, polysulfone and polyethersulfone homopolymers were sulfonated by treatment with chlorosulfonic acid. Then, analogous blends to the non-sulfonated ones were obtained and studied through the analysis of their glass transition temperature, microhardness, and electrical behaviour. In addition, a statistical method, suitable for the design of systems with optimized behaviour, has been applied to study these polymer blends and to predict the compositions with the best properties. Research on the area of polymer electrolyte membrane fuel cells has increased markedly over the last few years.

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Sizes and stabilities of multiplets and clusters in carboxylated and sulfonated styrene ionomers

Cited by 147 publications

References 9 publications

Effects of Organic Salts on Dynamic Mechanical Properties of Styrene Ionomers

Effects of Organic Salts on Dynamic Mechanical Properties of Styrene Ionomers

Proton conducting blends based on polysulfones and elastomers

Effect of Sulfonation on Thermal, Mechanical, and Electrical Properties of Blends Based on Polysulfones

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