Novel PLLA/magnesium composite for orthopedic applications: A proof of concept

This work aims to develop polymer/magnesium composites as new biodegradable and bioresorbable materials for osteosynthesis implants. The polymeric matrix will benefit from the higher strength and modulus of the Mg particles, whereas Mg will benefit from the surrounded protective polymeric matrix that will control its degradation rate. To provide a proof of concept a set of specimens were processed by combining solvent casting of PLLA (poly-l-lactic acid) loaded with 30 wt% of Mg particles and further molding by compression. Mechanical characterization reveals that reinforcing the polymer matrix with Mg particles improves its mechanical properties (hardness up to 340 MPa and yield strength up to 100 MPa). Interestingly, Young's modulus determined by ultramicroindentation increases up to 8 GPa. From the DSC analysis it follows that the unloaded and loaded polymer has similar crystallinity, which indicates that the improvement in mechanical properties is purely the effect of particle reinforcement.

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► We develop novel PLLA/Mg composites as biodegradable and bioresorbable materials.
► With Mg particles improves yield strength and elastic modulus of PLLA.
► Mg slightly decreases the glass transition temperature of PLLA.
► Mg does not induce crystal nucleation during cooling from the melt