Sulfonated polystyrene ionomers effects

In this work we used polystyrene-based ionomers.-Since there is no crystallinity in this type of ionomer, only the effect of ionic interactions has been observed. Eisenberg et al. reported that for styrene-methacrylic acid ionomers, the position of the high inflection point in the stress relaxation master curve could be approximately predicted from the classical theory of rubber elasticity, assuming that each ion pah-acts as a crosslink up to ca. 6 mol %. Above 6 mol %, the deviation of data points from the calculated curve is very large. For sulfonated polystyrene ionomers, the inflection point in stress relaxation master curves and the rubbery plateau region in dynamic mechanical data seemed to follow the classical rubber theory at low ion content. Therefore, it is generally concluded that polystyrene-based ionomers with low ion content show a crosslinking effect due to multiplet formation. More... 

A iKitable exception is the recent, application of EXAFS to plasticized Zn sulfonated polystyrene ionomers (73-711. Thi.s technique was used to investigate the effect of various diluents on the local struct.ure of the Zn cation. Plasticizers termed, "non-coordinatirig" (because they do not complex metal cations) - in particular, toluene, acetonitrile, and DOP - were shown to have a minimal influence on the cation s local structure. At most, these cause a slight increase in disorder, but they do not. alter the coordination structure around the cation. These diluents clearly partition themselves into the nonpolar regions of the ionomer. 

Hara M, Wu J, Lee AH. Effect of intia- and intermolecular interactions on solution properties of sulfonated polystyrene ionomers. Macromolecules 1988 21 2214-2218. 

In a few cases, the addition of minor amounts of immiscible or miscible polymers results in the nucleation of a crystalline polymer. The nucleation of PP by PE and polyamides (e.g., PAl 1) (immiscible) as well as the addition of PP to poly(butene-l) (miscible) has been noted in the literature [138-141 ]. The addition of LDPE to PP showed a reduction in the spherulite size of PP, attributed to an increase in nucleation density of the a-crystalline form along with an increase in the rate of growth of the -crystalline form [141]. The nucleation of polycarbonate by the zinc salt of sulfonated polystyrene ionomers was noted to occur with both miscible and phase separated blends [142]. Nanometer sized ionic aggregates appeared to contribute to the polycarbonate nucleation. A liquid crystalline copolyesteramide (Vectra-B950 ) was shown to accelerate the crystallization of poly(phenylene sulfide) [143]. This effect was not concentration dependent and did not change the level of crystallinity. 

The effect of adding sulfonated syndiotactic polystyrene ionomer 34... 

Tn the case of nonpolar diluents, very few studies have appeared in the literature. The Zn sulfonated polystyrene plasticized by 3.4 wt. % dodecane shows no change in either position, intensity or shape of the ionomer peak compared to that of the bulk polymer (27) this was taken to indicate that the ionic microphase is unaffected by this diluent. The Mn sulfonated polystyrene plasticized b,v up to 10 wt % DOP (Figure 11) shows a decrease in intensity of the peak, but no change in its shape or position (28). This was explained as a dilution effect of the ionic phase due to swelling of the matrix by the plasticizer. 

Similar solution behavior was reported(9-11) for sulfonate ionomers. Rochas eit al. (9) observed a polyelectrolyte effect for acrylonitrile-methallylsulfonate copolymers in DMF. Lundberg and Phillips(10) studied the effect of solvents, with dielectric constants ranging from c 2.2 to e 46.7, on the dilute solution viscosity of the sulfonic acid and Na-salt derivatives of sul-fonated polystyrene (SPS). For highly polar solvents such as DMF and dlmethylsulfoxide (DMSO, e 46.7) they observed a polyelectrolyte effect, but for relatively non-polar solvents such as THF and dioxane (c = 2.2) no polyelectrolyte effect was observed. Like Schade and Gartner, these authors concluded that polar solvents favor ionization of the metal sulfonate group while non-polar solvents favor ion-pair interactions. 

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