Polylactide/transition metal ion modified montmorillonite nanocompositeua critical evaluation of mechanical performance and thermal stability

Polylactide (PLA) nanocomposite was prepared by melt blending of PLA and transition metal ion (TMI) adsorbed montmorillonite (MMT). PLA nanocomposite was characterized for mechanical performance, and the results revealed that the tensile modulus, flexural modulus, and impact strength were increased marginally. The nanocomposite was optimized at 5 wt% of TMI-modified MMT (TMI-MMT) loading. Thermogravimetric analysis displayed increase in onset of degradation temperature, and differential scanning calorimetry showed marginal increase in glass transition temperature (Tg) and melting temperature (Tm) in case of PLA nanocomposites, when compared with virgin PLA. The flammability testing of nanocomposites indicated good fire retardance characters. X-ray diffraction patterns of TMI-MMT and the corresponding nanocomposites indicated an intercalation of the metal ions into the clay interlayer. Fourier transform infrared spectroscopy analysis indicate formation of [Zn(EDA)2]2+ and [Cu(EDA)2]2+ complexes in the MMT interlayer. Dynamic mechanical analysis shows increase in glass transition temperature (Tg) and storage modulus (E') in case of PLA nanocomposites reinforced with 5 wt% modified MMT. POLYM. COMPOS., 2012. (c) 2012 Society of Plastics Engineers