Preparation and Delamination Behavior of Lactate / Layered Double Hydroxide (LDH) Composites Using Reconstruction Method

The delamination behavior of a lactate/LDH composite prepared using the reconstruction method with a sodium lactate solution was investigated. The obtained composite showed that a strong peak around 2θ=11 ̊ that had been assigned as a basal reflection shifted slightly to lower angles: from 0.77 nm in starting LDH to 0.80 nm. This peak is assigned as a basal reflection of lactate-intercalated LDH (lactate/LDH). The interlayer distances of these diffractions were estimated about 0.32 nm, corresponding with the planate monomolecular state of lactate. Lactate contents of the obtained composites were 50–80 % against the anion exchange capacity of starting LDH, corresponding to increased concentrations of the reacted solutions. The XRD patterns of the gelated samples revealed no diffraction peak, but the XRD patterns of the casting sample after 80 ̊C drying exhibited diffraction peaks just as the as-received lactate/LDH composite did. The obtained lactate/LDH composite has new function of delamination and restacking. The obtained composite's delaminated size was 4–8 nm thick and 50–150 nm wide. Finally, the obtained lactate/LDH composite showed reversible delamination and smectite-like restacking functions. Key-words: Layered double hydroxide, Reconstruction, Lactate, Delamination, Nanosheet Original Research Paper J. Jpn. Soc. Colour Mater., 84〔1〕,2–6(2011)