Effect of DMSO on MA and SSNa polymerization rate constant and tacticity (part 2)

This study continues the exploration of the effects of DMSO on the polymerization rate constant and the tacticity of various monomers, this time focusing on two ionic monomers: methacrylic acid (MA) and sodium styrene sulfonate (SSNa). Polymerization was carried out under the same experimental conditions as for MMA. NMR spectroscopy was used to analyze the variation in the overall rate constant as a function of the initial concentrations of MA and SSNa, as well as the stereoregularity of PMA. The results revealed that the behavior of MA and SSNa in DMSO at 70 °C differs from that of MMA: the kp/√kt ratio increases with the initial concentration of MA, unlike MMA, while it remains stable for the SSNa concentrations studied. As for the tacticity of PMA, it remains predominantly syndiotactic. This study also identified concentration ranges of MA and SSNa where the variation in the overall rate constant remains negligible. This information is crucial for future copolymerization studies.