Mechanistic aspects of clay intercalation with amphiphilic poly(styrene-co-maleic anhydride)-grafting polyamine salts

The ionic exchange reaction of the smectite clays was affected by using a series of polymeric amine salts, synthesized by grafting poly(oxyalkylene)-diamines (POA-amine) onto poly(styrene-co-maleic anhydrides) (SMA). The comb-branched polyamines, comprised of a hydrophobic SMA backbone and multiple amine pendants, are amphiphilic in nature and capable of reducing the toluene/H2O interfacial tension (from 36 to 4 mN/m at 10(-3) wt % concentration). After acidification to cationic amines (-NH3+Cl-), the polyamines increased solubility in water and effectiveness for the clay intercalation. Depending on the structural variation and their amphiphilic property, the SMA-derived polyamines may intercalate with sodium montmorillonite to yield the organoclays with a broad range of XRD basal spacing from 12.9 to 78.0 angstrom. The intercalation profile is suspected to proceed with a critical d spacing expansion, due to hydrophobic phase separation from the embedded organics in the gallery confinement. The variations of hybrid basal spacing, TGA degradation pattern, and DSC analyses indicated the presence of at least two different types of intercalated hybrids. The finding on clay intercalating mechanism could lead to the synthesis of new organoclays for suiting versatile applications.