Novel modifiers for layered double hydroxides and their effects on the properties of polylactic acid composites

Hydrophobic modification of a carbonated layered double hydroxide (LDH) and its calcined equivalent was conducted by direct ion exchange reactions with three ionic liquids having the same phosphonium-based cation, but different anions. Among the ionic liquids, successful anionic intercalation was only carried out when calcined LDH reacted with a phosphinate anion containing ionic liquid, in excess of the stoichiometric amount. Ionic liquids containing a linear decanoate anion or the least bulky PF6 anion promoted the formation of a surface coating rather than increase of the interlayer space as confirmed by X-ray Diffraction, Infrared Spectroscopy, and Thermogravimetric analysis. The intercalated LDH was found to minimize the plasticizing/degradative effect of the ionic liquid on a polylactic acid PLA matrix and could be used as reservoir for the controlled release of the phosphorous containing anions for antibacterial or similar applications. (C) 2009 Elsevier B.V. All rights reserved.