Study of the structure-properties-processing relationship of nanocomposites based on poly (lactic acid) (PLA) and o-MMT

In this work, the effect of processing and nanoclay content on the mechanical properties of thin sheets obtained by cast sheet extrusion from a commercial grade of PLA and organomodified nanoclay has been investigated. Microstructure was studied using Transmission Electron Microscopy (TEM) and Wide Angle X-ray Scattering (WAXS), revealing the development of structures intercalated, although exfoliated clay layers and agglomerates were observed also. The mechanical properties have been assessed by uniaxial tensile tests. Finally, a deaging thermal treatment was applied to all prepared samples, in order to study the materials under two different states: relaxed (after the thermal treatment) and aged (before treatment). The tensile behaviour is affected by processing only in the case of aged PLA samples, whereas the addition of nanoclay is only significant at 2,5 % w/w. The de-aging treatment causes a change in the brittle-ductile behaviour evidenced in a significant increase in ductilily