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Mg–Al layered double hydroxides (LDH) are prepared by coprecipitation of Mg(NO3)2 and Al(NO3)3 and subsequently incorporated with poly(oxypropylene)-bis-amidocarboxylic acid (POP). When characterized by X-ray diffraction, the interlayer spacing of the synthesized POP/LDH hybrids were found to be spatially expanded, with basal spacing ranging from 33–94 A, proportionately correlated to the POP molecular weight of 400–4000 g/mol. With increasing POP molecular weight incorporation, a critical d-spacing is reached when the POP/LDH hybrids become hydrophobic. The organo-LDH units possessed an amphiphilic property and ability of dispersing in water, ethanol, and toluene. Furthermore, the hybrid was actually stable under basic conditions but structurally disintegrating at pH 2 through the release of POP organics into aqueous solution. The understanding of the mechanism involving basal spacing shrinkage and structure disintegration allows the future development of utilizing the POP-modified clay as pH-sensitive a...

The same poly(oxyalkylene)−amidoacids (POA−amidoacid) were incorporated into two different types of ionic clays, anionic layered-double-hydroxides (Mg−Al LDH), and cationic montmorillonite (MMT). Conventionally, the intercalation is an ionic exchange reaction, i.e. anionic organic salts for LDH and cationic salts for MMT. The successful intercalation using the neutral species of POA−amidoacid implies the existence of a new mechanism for clay intercalation. We prepared the POA−amidoacid from the reaction of maleic anhydride and poly(oxyalkylene)−diamine (POA−amine) with different hydrophobic and hydrophilic POA-backbones of 600−4200 molecular weight. The intercalation has resulted in the expansion of the clay basal spacing from 7.8 to 63 A for LDH and from 12.4 to 51 A for MMT, with a high Bragg’s regularity of XRD analyses. It appears that the driving force for the intercalation and organic incorporation into the silicate interlayer galleries is dissimilar to the counterion exchange but involving noncoval...