USE OF NEW SILICA FILLERS AS ADDITIVES FOR POLYMERS USED IN PACKAGING OF FRUITS

ROMINA ARRECHE, MIRTA BLANCO, JOSÉ MIGUEL MARTÍN-MARTÍNEZ, PATRICIA VÁZQUEZ

Dresden

Conferencia; EUROFILLERS 2011; 2011

The objective of this work is to synthesize nanosilicas with different degree of hydrophobicity prepared by the sol-gel method. Two modifiers, 3-aminopropyl triethoxysilane (APS) and 1,1,1,3,3,3–hexamethyldisilazane (HMDS), were added during the synthesis. The new nanosilicas were added to commercial biopolymer (Hexamoll Dinch, BASF) intended for packaging of apples and pears. The nanosilicas were characterized by X-ray diffraction, transmission and scanning electron microscopies, potentiometric titration, porosity and specific surface area, hydrophobicity/hydrophilicity by wetting tests. Colorimetry was used to assess the effect of the nanosilica additive in contact with apple pulp as the change in color with time can be related to the efficiency of the packaging material. Addition of silica obtained with HMDS and APS increased the hydrophobicity of the biopolymer. Titration of modified silica with APS and HMDS showed an abrupt decrease in acidity compared to the unmodified silica. TEM analysis of the silica prepared with APS and HMDS showed that the increase in HMDS maintained the spherical shape of the silica and the addition in the biopolymer kept his shape. On the other hand, the biopolymer materials showed similar morphology, forming clusters or agglomerations. Finally, the brightness of the pieces of apple pulp in contact with the modified silica slightly increases with respect to the unmodified silica, and similar behavior was observed in the Hue angle.