Surface grafting of modified PLA onto starch nanocrystals.

GARCÍA, N.L.; LAMANNA, M.; D'ACCORSO, N.; DUFRESNE, A.; ARANGUREN, M.; GOYANES, S.

Còrdoba, Argentina

Simposio; ARCHIPOL 2009. VIII Argentine Polymer Symposium; 2009

Starch, a renewable biodegradable and very low cost material, is not yet used at its full potential, because of its low mechanical properties and its strong hydrophilic character. In recent years, the addition of starch nanoparticles to a maize starch matrix was reported (Angellier et al., 2006 ). This work led to the present study using cassava starch as a matrix material. We reported that the addition of 2.5 wt.% nanoparticles increased elastic modulus and decreased water vapor permeation in a 50 wt% with respect the starch matrix (Garcia et al., 2009). However, these values do not meet the requirements of the packaging industry. Another important issue is the mixture of starch with other biodegradable polymers, in particular polylactic acid (PLA). PLA is also a biodegradable polymer synthesized from renewable resources, and with mechanical properties comparable to those of polystyrene, which makes it an ideal material for applications in the area of packaging. However, its low elongation at break and its high cost limit its applications. From the viewpoint of barrier properties, its hydrophobic nature is useful in terms of permeability to water vapor. In recent years many efforts have been made to make starch-PLA composites since this seems to be the most promising combination for starch -based packaging (Wang et al., 2008; Jang et al., 2007). The biggest problem with this mixture is the poor interfacial adhesion between hydrophilic starch grains and the hydrophobic PLA. With the ultimate goal of solving this problem we propose the functionalization of starch nanoparticles with PLA and their use as a link between starch and PLA. This paper presents the methodology used to achieve the functionalization of nanoparticles with PLA