Adsorption of cellulose derivatives onto montmorillonite: a SEC–MALLS study of molar masses influence

Adsorption properties of two commercial neutral cellulose derivatives: hydroxyethylcellulose (HEC) and hydrophobically modified hydroxyethylcellulose (HMHEC) onto montmorillonite were investigated in pure water and in salt solution. Regardless of the polymer, the adsorption onto clay is always larger in pure water than in salt solutions. In other respects, adsorption of the associative HMHEC is always slightly enhanced in comparison with its parent HEC. For both polymers, only simple layer type of adsorption is evidenced (Scatchard linearisation). Finally, a SEC–MALLS study conducted with HEC has shown that adsorption on clay occurs preferentially for the lower molar masses. The adsorbed amount of HEC on clay is larger for the lower molar masses.