The Influence of Miscibility of Some PLA-Based Bio-Hybrids Designed for 3D Printing and Medium-Life Applications on Their Physical Aging and Thermodynamic Stability

The aim of this article was to identify the dependence of the physical aging of PLA-talc-PCL bio-hybrids, with or without a nucleating agent (NA), produced by melt compounding and designed for 3D printing for medium-life applications, on the degree of miscibility, and to identify a formulation with a heat deformation temperature (HDT) of practical interest and thermodynamical stability for at least two years. The obtained bio-hybrids were characterized to illustrate their miscibility and long-term thermodynamic stability, both initially and after two years. The preservation of properties over time was analyzed by examining the observed physical aging, since its can be associated with changes incompatible with 3D-printed items used as structural automative components. Without using NA, two partially miscible bio-hybrids with multiphase, polymorphic morphology were achieved, which showed strong physical aging and thermodynamic instability over two years. The use of NA led to a bio-hybrid with a relatively narrow single melting peak, which showed good miscibility, without physical aging or thermodynamic instability over the two-year period. The morpho-structural and functional characterization of the selected formulation will be further investigated and possibly corrected, to advance to the next level of scale-up.