Synthesis and characterization of biodegradable poly(L-lactide)/layered double hydroxide nanocomposites

The effects of layered double hydroxide (LDH) composed by calcium/aluminum and magnesium/iron as divalent/trivalent cations and intercalated with dodecyl sulfate anion in the properties of poly(l-lactide) (PLLA) were analyzed. Two PLLA nanocomposites were produced by in situ intercalative bulk polymerization using 1 and 2 wt% of LDH. The PLLA nanocomposites were analyzed by X-ray diffraction (XRD), Fourier transform infrared spectroscopy, thermogravimetric analysis, differential scanning calorimetry, and ultraviolet-visible spectroscopy (UV-VIS). XRD results demonstrated that PLLA nanocomposites showed a good dispersion of LDH in the polymeric matrix, which may have caused an increase in thermal stability indicated by thermogravimetric analysis. UV-VIS analyses showed that PLLA nanocomposites presented lower transmittance values when compared to the neat PLLA, which is an interesting characteristic for plastics used in food packaging. This enhancement in the properties of PLLA nanocomposites can enlarge the range of applications of this material in several areas.