Poly(lactic acid) nanocomposites: comparison of their properties with montmorillonite and synthetic mica(II)

Our study was to clarify the intercalation of polymer chains to organoclays and to improve the thermo-mechanical properties. Two organoclays were synthesized. One was a montmorillonite modified with hexadecylamine (C-16-MMT); the other was a fluorinated-mica modified with hexadecylamine (C-16-Mica). Dispersions of organoclays with poly(lactic acid) (PLA) were by using the solution intercalation method at different organoclay contents to produce nano-scale composites. The maximum ultimate tensile strength was observed for blends containing 4 wt% of either of the two organoclays and decreased with further increases in the organoclay content. The initial modulus increased with increasing organoclay content up to 4 wt% for C-16-MMT. When the C-16-MMT content was greater than this critical wt%, the modulus of the hybrids started to decrease. In contrast, the initial modulus of the hybrids using C-16-Mica increased continually with increasing clay content from 2 to 8 wt%. The tensile properties of the C-16-Mica hybrids were higher than those of the hybrids containing C-16-MMT. The optical translucency was not affected by the organoclay content up to 6 wt%; however, the films containing 8 wt% organoclays were slightly more cloudy. (C) 2003 Elsevier Science Ltd. All rights reserved.