Caracterização e degradação de filmes PBAT aditivados com estearatos metálicos.

Abstract

Biodegradable plastics are a new class of polymers which have been extensively explored in order to minimize environmental problems and meet industrial requirements. One of the most promising biodegradable polymers for use in packaging is poly (butylene adipate-co-terephthalate) (PBAT) which, however, needs to be previously aged of photo-oxidized in order to loose mass at fast rates when composted. In the present study cobalt and magnesium stearates were added to a biodegradable PBAT matrix in order to evaluate the effect of these additives on the mechanical and thermal properties, gas permeability and degradation of films made with these systems. PBAT / stearate systems were processed in an internal mixer, ground up and extruded as flat films. The tensile, thermal and morphological properties of the films before the degradation tests (biodegradation and hydrolytic degradation) were evaluated. The results show that the incorporation of the additives to the PBAT initiates degradation of the polymer matrix during processing, and accelerates crystallization. The mechanical properties of the films decreased with the addition of the stearates in the polymer matrix. Finally, degradation studies (biodegradation and hydrolytic degradation) confirm that cobalt stearate was more effective in accelerating degradation of PBAT than magnesium stearate.