Physico Mechanical Properties of Biodegradable Starch Nanocomposites

NANCY LIS GARCIA; LAURA RIBBA; ALAIN DUFRESNE,MIRTA ARANGUREN, SILVIA GOYANES,

MACROMOLECULAR MATERIALS AND ENGINEERING (PRINT)

WILEY-VCH Verlag GmbH & Co. KGaA

Lugar: Weinheim; Año: 2009 vol. 294 p. 169 - 177

1438-7492

New nanocomposites of cassava starch reinforced with waxy starch nanocrystals were prepared. It is worth noting that the resultant nanocomposites (containing 2.5 wt.-% of nanocrystals) showed a 380% increase of the rubbery storage modulus values (at 50°C) and a decrease in the water vapor permeability of 40%. X-ray spectra show that the composite was more amorphous than the neat matrix, which was attributed to higher water equilibrium content in the composites as can be seen from the water absorption test. Thermogravimetric analysis confirmed this last result and its thermal derivative suggests the formation of hydrogen bonding between glycerol and the nanocrystals, which were also concluded from Fourier transform infrared spectroscopy. The reinforcing effect of starch nanocrystals can be attributed to strong filler/matrix interactions due to the hydrogen bonding. Besides, the decrease of the permeability suggests that the nanocrystals are well dispersed, being few the interactions filler/filler.