Effect of Combining Ethylene/Methyl Acrylate/Glycidyl Methacrylate Terpolymer and an Organoclay on the Toughening of Poly(lactic acid)

Blends of poly(lactic acid) (PLA) and ethylene/methyl acrylate/glycidyl methacrylate terpolymer (EMA-GMA) with and without the addition of an organoclay were prepared by melt mixing in a twin screw extruder. Mechanical, morphological, structural, and rheological properties of the systems have been investigated as function of its compositions. The impact strength (IS) of PLA increased with the addition of EMA-GMA. Furthermore, the addition of 2.5 wt% of organoclay to the PLA/EMA-GMA blend promoted improvements in the mechanical properties, such as IS, tensile strength, and strain-at-break. Further addition of organoclay, 5 wt%, led to a formation of a double percolated network, where the clay particles form bridges across EMA-GMA droplets and glue them together, however, without coalescence. In addition, morphological and wide-angle X-ray scattering analyses evidenced that the clay presents a partially exfoliated structure and that remains inside the EMA-GMA droplets, probably as a consequence of the approach used to produce the systems. (C) 2013 Society of Plastics Engineers