Sulfonate with phthalate plasticizers

The data thus far have shown that S-PS can be plasticized effectively with respect to backbone and ionic domain plasticizers. By appropriate choice of the plasticizer type either the PS backbone or the ionic domains can be plasticized preferentially. By appropriate control of the metal sulfonate content and the polarity of the plasticizer used, flexible S-PS compositions possessing useful tensile properties are feasible. While this approach has substantial merit, it is apparent that simply increasing the level of a phthalate plasticizer to improve melt flow results in a substantial decrease in useful tensile properties. It would be desirable to use a given level of backbone plasticizer and adjust the melt flow of the entire composition by independently plasticizing the ionic domains. One approach to achieve this objective has been described in the plasticization of ionic groups in metal-sulfonated ethylene propylene terpolymers (9). In those systems, the incorporation of metal carboxylates as plasticizers can improve both flow behavior and tensile properties. It is of interest to determine if this class of plasticizers can be combined with the phthalate plasticizers used for the S-PS backbone to provide an improved balance of flow behavior and tensile properties for S-PS s. 

The direct potentiometric determination (using a cation-selective membrane electrode) of procaine and some physiologically active amines in pharmaceuticals has been reported [70]. The sensing membrane was formed from PVC plasticized with dibutyl phthalate, and contained 0.1 mM trioctyloxybenzene-sulfonic acid in dibutyl phthalate. The reference solution was a mixture of 1 mM solution of the organic base and hydrochloric acid. Response was found to be linear over a wide concentration range, and the method was highly selective. 

Dioctyl phthalate (DOP) was used as a representative of the class of backbone plasticizers and glycerol as a plasticizer for ionic groups. Both systems were studied with S-PS (sodium salt) as the base polymer in which the base resin had a sodium sulfonate content of 1.78 mol %. Various quantities of the two aforementioned diluents were added to this resin. 

Souza et al. examined the influence of plasticizers, such as dioctyl phthalate (DOP) and cashew nut shell liquid (CNSL), on the electrical properties of blends based on PANI (doped with dodecylbenzene sulfonic acid) and SBS (styrene-butadiene-styrene) copolymer [106,107]. EPR experiments revealed an increase in polaron mobility (a decrease of AHpp) as the amount of plasticizer in the blend was increased, with the effect being more pronounced for CNSL (Figure 23.25). This phenomenon is known as a second doping, and is achieved without any additional protonation of PANI rather, it is due to an enhanced conformational... 

---