Water vapor permeability and tensile properties of poly(l-lactic acid)/synthetic mica nanocomposites prepared by melt blending

Poly(L-lactic acid)/synthetic mica (Somasif) nanocomposites were obtained by melt blending in a mixing chamber according to a factorial experimental design and considering the following variables: temperature, rotor speed, nanofiller concentration and residence time. Relatively high degree of dispersion was attained by the melt processing which generates poly(L-lactic acid)/synthetic mica nanocomposites with particle size even in the order of 40 nm. The tensile properties and the water vapor permeability of these nanocomposites were evaluated. The introduction of synthetic mica into neat poly(L-lactic acid) decreased the water vapor permeability by about 50%. The variables which most affected the tensile properties were the mixing time and clay concentration, but the levels studied or the degree of intercalation/exfoliation were insufficient to significantly improve the tensile properties of poly(L-lactic acid)/somasif mica nanocomposites.