Dynamic mechanical and morphological studies of styrene-co-methacrylate and sulfonated polystyrene ionomers containing aliphatic dicarboxylate salts

Abstract

This study examined the effects of the sodium salts of aliphatic dicarboxylic acids (DCAs) on the dynamic mechanical properties and morphology of two sets of poly(styrene-co-sodium methacrylate) (MNa) and poly(styrene-co-sodium styrenesulfonate) (SNa) ionomers. When the DCA content was relatively low, the ionic moduli of the MNa and SNa ionomers increased but the matrix and cluster glass transition temperature (T g ) did not change significantly. The increasing ionic modulus was almost independent of the type of the ionic groups of the ionomer, and the chain length of DCAs. When a large amount of the sodium succinate (DCA4) was added to the MNa and SNa ionomers, the ionic moduli of the two ionomers increased strongly but the matrix and cluster T g 's increased slightly and significantly, respectively. In the case of sodium hexadecanedioate (DCA16), DCA16 increased the ionic moduli of the two ionomers. The addition of DCA16 changed the matrix and cluster T g 's of the MNa ionomer slightly, but decreased the cluster T g of the SNa ionomer significantly with no change in the matrix T g . In addition, the DCA-containing ionomers showed an X-ray diffraction peak indicating the presence of ordered domains of DCAs in the ionomers. Hence, DCA4 acts mainly as a reinforcing filler in MNa and SNa systems. In the case of DCA16, it initially behaved like a filler but also functioned as a preferential plasticizer for the clusters at high content.

Tangible plasticization/filler effects of sodium salts of dimer acids on the mechanical properties of styrene ionomers

“…Since aliphatic dicarboxylate can form the filler particles more easily, the filler effect of HD would be stronger than that of DA. 5,6 In addition, as expected, the plasticization effect of DA is more profound than that of HD because of the nature of DA, i.e. mixture of various DAs.…”

“…In the case of the loss tangent and storage modulus curves of the PSSNa and PSMANa ionomers containing HD, even though we obtained them by using the samples that we prepared in the present work, we do not show them here because similar results had already been shown elsewhere. 5,6 We only use the T g s and ionic moduli of HD-containing ionomers to compare them with those of the ionomers containing DA. The data can be fitted to linear functions and the intercepts and slopes of the fitted lines for the T g s of PSSNa and PSMANa ionomers containing either DA or HD are listed in Table 1.…”

“…5 It was also found that when a large amount of sodium hexadecanedioate was added to the poly (styrene-co-sodium styrenesulfonate) (PSSNa) ionomer, the organic salt acted both as a reinforcing filler and as preferential plasticizer for the clustered region of PSSNa ionomers. 6 On comparing these results with those of other systems, it was proposed that the amount of the additives was responsible for the increasing ionic modulus.…”

“…1 Only a few studies have been performed on the effects of the aliphatic dicarboxylic acid salts on the properties of amorphous polystyrene (PS)-based random ionomers. 5,6 It was suggested that the di-functional organic salts became phase-separated and acted mainly as filler particles in poly(styrene-co Na-methacrylate) (PSMANa) ionomers. 5 It was also found that when a large amount of sodium hexadecanedioate was added to the poly (styrene-co-sodium styrenesulfonate) (PSSNa) ionomer, the organic salt acted both as a reinforcing filler and as preferential plasticizer for the clustered region of PSSNa ionomers.…”

“…monocyclic, bicyclic, acyclic DA (Scheme 1), have been prepared from waste fatty acid cooking oils (vegetable and animal oils) as raw materials; the detailed compositions of the DAs are not known at present, but it is known that the reaction condition could control the compositions. From our previous studies, 5,6 we have known that the DA obtained from the waste cooking oil, being eco-friendly additives, can also be utilized as filler/plasticizer for the PS-based ionomers. Thus, in this study, we attempted to investigate the effects of the addition of sodium salts of DA compounds to the PS-based ionomers on the mechanical properties and morphology of the ionomers.…”