Development of nanocomposite for use in packaging industry

Layered double hydroxides (LDH) are a class of anionic clays where the metal layers are positively charged and the charge balance is provided by the interlayer exchangeable anions. The chemical composition of LDHs is generally expressed with the [MII1-xMIII x(OH)2]x+(An-)x/n.yH2O formula where MII and MIII represent divalent and trivalent metal cations, respectively, and An- represents the interlayer anion.In this study, Mg-Al- LDH and Mg-Al LDH of modified with dodecyl sulfate (DS) ions were synthesized with Mg/Al ratio of 2 and 3 by co-precipitation method. Then, polylactide (PLA)/ anionic clays, nanocomposities were prepared by solution casting technique.The characterization of nanocomposites prepared were investigated by using contact angle measurements, surface energy calculations, FTIR spectroscopy, X-ray diffraction (XRD), differential scanning calorimetry (DSC), atomic force microscopy (AFM) and transmission electron microscopy (TEM). Oxygen gas and water vapor barrier properties of PLA and nanocomposites were measured.It is obtained that PLA/SDS-Mg-Al LDH (3:1) %5 nanocomposite gave the maximum oxygen barrier property result due to the compatibility of clay and polymer matrix. The clay content in PLA polymer enhanced the oxygen barrier property up to %23.5.Key Words: Layered double hydroxide, Hydrotalcite, Sodium dodecyl sulfate, Poly(lactic acid), Nanocomposite, Food packaging