PLA-based bionanocomposites with modulated degradation rate: preparation and processing by microinjection molding

The aim of this work has been to obtain bionanocomposites with a degradation rate which can be modulated in time, so that it can be possible to decide a priori the time after which the material will disappear in a given environment. At the same time, the material should preserve its properties during processing. Several mixtures of PLA (4032D, 4060D) and LDH of cation composition Mg2Al organo-modified with organic acids (succinc, fumaric and ascorbic acid) have been obtained by extrusion. From the extruded materials there were obtained films by compression molding; these films were then subjected to hydrolysis tests. The experimental results show that for samples loaded with LDH-organic acid (in particular LDH-succinic acid), there is an increase in the time needed for degradation, and a decrease in this time for samples loaded with organic acid alone. From the selected material (PLA + LDH-succinic acid) and from pure PLA, biphasic samples (half amorphous and the other half crystalline) have been obtained by micro-injection molding. Also in this case, the experimental results show an increase for the loaded samples in the time needed for degradation compared to pure PLA both for the crystal phase and for the amorphous one, and in particular the presence of a degradation profile within the same sample is observed. [edited by Author]