Functionalization of montmorillonite by end-chain mono-cationic polystyrene and end-chain mono-cationic poly(styrene-b-2-hydroxethyl acrylate)

Iodo-terminated polystyrene (PS-I) and iodo-terminated poly(styrene-b-2-hydroxyethyl acrylate) (PS-b-PHEA-I) were reacted at room temperature with dimethylethylamine (DMEA) and triethylamine (TEA) respectively, affording PS and PS-b-PHEA with one quaternary ammonium chain-end functionality referred to as PS-cationic and (PS-b-PHEA)-cationic, as was confirmed by Fourier transform spectroscopy (FT-IR) and matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF). PS-cationic and (PS-b-PHEA)-cationic were successfully used for the modification of montmorillonite surface (Mt), as was confirmed by FT-IR, thermogravimetric analysis (TGA), and small angle X-ray scattering (SAXS). The effect of the solvent polarity on the degree of Mt modification was investigated. FT-IR, TGA and SAXS also showed that PS-cationic and (PS-b-PHEA)-cationic do undoubtedly interact with the clay mineral surface via ion exchange reaction. The maximum mol% (relative to CEC) of (PS-b-PHEA)-cationic incorporated into the interlayer space was found to be greater than the amount of PS-cationic.