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Migration and leaching of plasticizer from plasticized poly(L-lactide)/olive stone flour composites

Thermally induced migration of tributylacetyl citrate (TBAC) from plasticized poly(L-lactide) (PLLA) and plasticized PLLA/olive stone flour (OSF) composites were investigated. Isothermal heating was conducted at 120°C and 150°C in a vented oven. Change of thermal properties was investigated by differential scanning calorimetry (DSC). The weight loss of plasticizer increases with heating time and at 120°C is lesser than at 150°C. Migration of TBAC results in cracks and changed colour of material. The plasticized PLLA/OSF composites showed resistance to cracking. As the amount of OSF increases the resistance to cracking increases. Kinetic analysis of TBAC migration shows that activation energy related to concentration of plasticizer of all compositions is almost the same leading to the conclusion that OSF doesn't affect the thermally induced migration. DSC analysis reveals that thermal properties of material are greatly influenced by migration temperature, independently of its composition. Migration of plasticizer increase Tg, Tm, Tc and Xc of material and that increase is more pronounced at 150°C. Increase of OSF content in the plasticized PLLA/OSF composites hasn't showed any influence. DSC analysis confirmed migration test results.

Poly(L-lactide) ; Tributylacetyl citrate ; Olive stone flour ; Migration

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