Dimethyl-5-sulfoisophthalate sodium salt (often abbreviated as DMSIP-Na or DM-5-SIP sodium salt) is a specialty sulfonated aromatic diester used primarily as a comonomer or modifier in polyester and related polymer systems. By introducing sulfonate functionality into polymer backbones, it improves hydrophilicity, dyeability, dispersion behavior, and compatibility with water-based systems. This...