Intercalation of layered double hydroxides by poly(oxyalkylene)-amidocarboxylates:tailoring layered basal spacing

摘要

Mg-Al layered double hydroxides(LDHs)were intercalated with various molecular-weight poly(oxypropylene)-bis-amidoacid salts(POP-acid),synthesized from polyoxyalkylene-diamines and maleic anhydride.The intercalation involves an ionic exchange reactioruof LDHs at 120 deg C and under N2 atmosphere in an autoclave to afford a series of organoclays with a maximal basal spacing of 92 A,revealed by X-ray diffraction and transmission electron microscopy analyses.The unusually wide interlayer spacing was ascribed to the self-alignment of the hydrophobic POP backbone in the layer confinement,hi contrast,the intercalation of poly(oxyethylene)-bis-amidoacids(POE-acid)afforded a low basal spacing(7.8 A)due to their oxyethylene-backbone interaction with the layered surface.The resultant POP-and POE-acid intercalated LDHs also exhibited different dispersing properties in toluene or water.Particularly,the organically-modified and space-enlarged hybrids with a proper amount of the embedded POPs possessed an amphiphilic property of lowering the toluene/water interfacial tension.