Comparison between conventional and additive processing of polylactic acid subjected to multiple recycling and lauroyl peroxide additivation

Polylactic acid is one of the most used materials for polymer parts manufacturing, given its good mechanical properties combined with reusability and environmental-friendly nature. This work analyzes the effects of mechanical recycling and lauroyl peroxide additivation on the physical and mechanical properties of polylactic acid processed through conventional and an additive manufacturing processes, namely compression moulding and fused deposition modelling. Differential scanning calorimetry analysis, three-point bending and tensile tests were considered to assess the effects of the mentioned actions. The results showed that the effects of recycling become evident after the third iteration, with a notable inhibition effect caused by the addition of lauroyl peroxide. Furthermore, the experimentation demonstrated that the impact of recycling and additives on the ultimate properties of the products depends on the transformation process used, highlighting a greater sensitivity of the fused deposition modelling process compared to the traditional compression moulding one.