Ionic plasticization

SYNTHESIS AND THERMAL PROPERTIES OF IONIC PLASTIC CRYSTAL ELECTROLYTES... 

In order to enable melt processing of ion containing polymers, such as S-EPDM, it is necessary to introduce a mechanism that weakens the ionic interactions. This can be achieved by the addition of a polar ingredient that would plasticize" ionic domains at elevated temperatures only. A variety of such ionic-plasticizers were described by Makowski and Lundberg (10). A particularly attractive combination was found to be zinc stearate with a zinc salt of S-EPDM. It was shown that for such a combination melt... 

This paper attempts to further explore the modification of ionic associations by a crystalline ionic plasticizer, such as zinc stearate, at the solid state. Mechanical properties, swelling behavior, and morphological aspects were studied in order to better understand the role of such crystalline polar additives. 

The sulfonation of EPDM as shown in Reaction 41b has recently been announced to be under commercial development by Uniroyal (78). Sulfonated EPDM can be classified as an ionic thermoplastic elastomer, whereby ionic interactions between chains act as thermally reversible cross-links. Above certain temperatures these ionic interactions break down, and plastic flow can occur. Upon cooling, these ionic cross-links reform to give the desired property characteristics. To enhance the processability of sulfonated EPDM an ionic plasticizer "ionolyzer" (i.e., zinc stearate) is added to about 20 phr (parts per 100 rubber). Care must be taken to ensure complete neutralization, because it was observed that residual acid can result in covalent cross-linking during fabrication. 

TanUd, R., K. Matsumoto, T. Nohira, and R. Hagiwara. 2014. All solid-state electrochemical capacitors using A/,A/-dimethylpyrrolidinium fluorohydrogenate as ionic plastic crystal electrolyte. Journal of Power Sources 245 758-763. 

Two groups of plasticizers are reported as being used in ionomers - regrrlar and ionic plasticizers ... 

In addition to the more conventional plasticizers, ionic plasticizers are also used. This is specific case of plasticization which acts on different segments of ionomers. lonomers are composed of polymeric chains which have certain number of ionic groups. The ionic groups that are distinct from the nonpolar polymer chain form aggregates known as mul-tiplets. The multiplets are ionic crosslinks surrounded by matrix of polymer chains. At a certain ionic content, the restricted mobility of ionic crosslinks becomes the significant factor in determining the glass transition temperature of the ionomer. 

Figure 11.12. Effect of fraction of stoichiometric concentration of 2-ethylhexyl-p-dimethylaminobenzoate used for ionic plasticization of poly(styrene-b-isobuty-lene-b-styrene), having 4.7% sulfonated phenyl units, on glass transition temperature, Tg, and temperature at which tan6=3. [Data from Storey R F Bau D W, Polym. Eng. Sci., 39, No.7, July 1999, p. 1328-34.]...

The addition of ionic plasticizer such as sodium salt of dodecylbenzenesulfomc dramatically increases the ability of the ionomer to ciystallize. Figure 11.11 shows that the heat of fusion of an isothermally crystallized ionomer increases with the addition of a plasticizer. This behavior is attributable to the separation of ionic domains, which enhances the molecular mobility of the crystalhzable chains and also increases the crystallization rate as the amount of plasticizer increases. " ... 

Comparing Figures 11.12 and 11.13, it is possible to conclude that regular plasticizers have a preferential effect on polymer matrix whereas ionic plasticizers affect ionic clusters. This clarifies the distinction between the mechanisms of their action as indicated in Section 11.15.4. 

Plasticizers are used in polymethylmethacrylate in very specific cases only. PMMA ionomers are the most likely nsers of the ionic plasticizers. 

Rana UA, Forsyth M, MacFarlane DR, Pringle JM (2012) Toward protic ionic liquid and organic ionic plastic crystal electrolytes for fuel cells. Electrochim Acta 84 213-222... 

O.N., Halogen-free chelated orthoborate ionic liquids and organic ionic plastic crystals, J. Mater. Chem. 22 (14), 6928-6938 (2012). 

Rana, U.A., Vijayaraghavan, R., MacFarlane, D.R. and Forsyth, M., Anorganic ionic plastic crystal electrolyte based on the triflate anion exhibiting high proton transport, Chem. Commun. 47 (22), 6401-6403 (2011). 

Non-ionic polymer gel swollen with dielectric solvent is shown to be extremely deformed, as is the non-ionic polymer plasticized with non-ionic plasticizer. 

Ikeda R, Ishimaru S, Tanabe T, Nakamura D (1995) A noble ionic plastic phase of cesium formate studied by H, and Cs NMR and electrical conductivity measurements. J Mol Struct 345 151-157... 

Moriya K, Matsuo T, Suga H (1988) Thermodynamic properties of alkali and thallium nitrites the ionic plastically crystalline state. Thermochim Acta 132 133-140... 

Pas SJ, Pringle JM, Forsyth M, MacFarlane DR (2004) Thermal physical properties of an archetypal organic ionic plastic crystal electrolyte. Phys Chem Chem Phys 6 3721-3725... 

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