The Influence of Iron Particles and Polyethylene Glycol on Selected Properties of Polylactide-Based Composites

This article presents the characteristics of composites comprising polylactide combined with iron powder, from 1 to 10 wt.%, and nanoiron powders with a mass fraction from 0.1 to 1.0 wt.%, along with polyethylene glycol. A total of nine composites were prepared, with three variations each: polylactide with iron powder, polylactide with nanoiron powder, and polylactide with micro- and nanoiron powder combined with polyethylene glycol. The samples underwent mixing, extrusion, and pressing processes. To assess the properties of the resultant composite samples, ultimate tensile tests, Shore hardness tests, fracture surface observations, degradation tests in 0.9% saline solution, and DSC analyses were conducted. The findings revealed that nanoiron powder incorporated into the polylactide matrix demonstrates better tensile properties, both strength and elongation, compared to those incorporating micrometric-iron powder only. However, both iron powder additions led to a decrease in the total elongation of neat polylactide acid except for the composite with 1% nanoiron. Furthermore, all samples with polyethylene glycol addition show a lower Young's modulus compared to neat PLA. In general, the microiron powder decreases the Young's modulus of PLA composites, whereas the nanoiron powder slightly increases the Young's modulus of these samples. Polyethylene glycol, a biocompatible substance, emerged as a suitable candidate for enhancing the adhesion of iron particles and improving the strength and elongation properties of the tested composites. Also, fracture surface analysis of the tensile samples suggests using fine nanoiron particles instead of coarse ones to improve the mechanical properties due to the stronger bonding of nanoiron particles to the PLA matrix.