The effect of processing conditions and polymer crystallinity on the mechanical properties of unidirectional self-reinforced PLA composites

The narrow process temperature window available to consolidate self-reinforced PLA composites is one of the challenges for the application of this type of composites. In the present work, the effect of the consolidation temperature on the polymer crystallinity and the mechanical performance of self-reinforced PLA composites is studied and characterized. On the filament level, the results show that the Young’s modulus of PLA reinforcement filaments increases with exposure to consolidation temperature (12%) and the strength at break decreases (30%). With an additional annealing process, the Young’s modulus of a semi-crystalline PLA matrix may increase, while the properties of the PLA reinforcement filaments remain unaffected. On the composite level, the results show that an increase of the consolidation temperature results in lower strength and higher strain at break. Based on the experimental findings, optimal processing conditions for the selected PLA grades are recommended to produce self-reinforced PLA composites.