Surface modification of montmorillonite by the use of organic cations via conventional ion exchange method

Abstract

The main problems in synthesis polymer clay nanocomposites (PCNs) with nanoclay filler is the nanoclay was not compatible to most of polymer matrix due to its hydrophilicity which is often causes agglomeration of the nanoclay in the polymer matrix. Surface modification of nanoclay for a good compatibility with polymer matrix is the most important step to achieve homogenous dispersion of clay platelets in polymers. Modification of nanoclay montmorillonite (MMT) can be done through conventional ion exchange method using cationic surfactants. Montmorillonite (MMT) was modified with several cationic surfactants based on its cationic exchange capacity (CEC). The effect of chemical composition of modified MMT on the basal spacing were evaluated by small angle x-ray diffraction (SAXS), the highest basal spacing expanded from 1.21 nm to 2.00 nm showed the intercalation of the surfactant ion into the intergalerry of sodium montmorillonite clay layers which caused increasing of surface area and porosity. FTIR spectra shows the successful of inserting alkyl groups from cationic surfactant in interlayer space of montmorillonite. Organophilization reduces the energy of sodium montmorillonite and improves its compatibility with organic polymer. Dispersion analysis and contact angle results shown the surface wettability of montmorillonite was enhanced from hydrophilic to organophilic and resulting good solubility in monomer phase.