Mechanical and degradation properties of biodegradable Mg strengthened poly-lactic acid composite through plastic injection molding

•Full biodegradable Mg alloy strengthened PLA composite rods were prepared by plastic injection molding.•Uncoated, AO and MAO coated Mg rods were selected as insert to prepare PLA composite rods.•Interfacial bonding force between PLA and Mg plays a very important role in PLA/Mg composite rods.•Porous MgO coating improved the mechanical properties of composite rods by mechanical locking and chemical bonding.

Full biodegradable magnesium alloy (AZ31) strengthened poly-lactic acid (PLA) composite rods for potential application for bone fracture fixation were prepared by plastic injection process in this work. Their surface/interfacial morphologies, mechanical properties and vitro degradation were studied. In comparison with untreated Mg rod, porous MgO ceramic coating on Mg surface formed by Anodizing (AO) and micro-arc-oxidation (MAO)treatment can significantly improve the interfacial binding between outer PLA cladding and inner Mg rod due to the micro-anchoring action, leading to better mechanical properties and degradation performance of the composite rods.With prolonging immersion time in simulated body fluid (SBF) solution until 8 weeks, the MgO porous coating were corroded gradually, along with the disappearance of original pores and the formation of a relatively smooth surface. This resulted in a rapidly reduction in mechanical properties for corresponding composite rods owing to the weakening of interfacial binding capacity. The present results indicated that this new PLA-clad Mg composite rods show good potential biomedical applications for implants and instruments of orthopedic inner fixation.

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