Pla granules

PLA granules (Goodfellow, UK) were dissolved in a glass container containing 5% acetone, heated to 50°C, and stirred vigorously for approximately 4 h. Mg alloy AZ91 (9 wt% Al, 1 wt% Zn), both coated and bare, was applied as a reinforcement core. Coated samples were made as follows: AZ91 strips with specific size were rinsed in 35% hydrochloric acid (OCI, Korea) to clean the surface and immersed in 50% hydrofluoric acid (Duksan, Korea) for 8 h to form the fluoride coating. Then, AZ91 strips were washed using deionized water and ethanol. Finally, AZ91 strips were wholly blow-dried. Bare samples (uncoated) were treated in the same way, except for being immersed in HF (Table 1).
The PLA solution was first laid in a metal mold, followed by a Mg alloy AZ91 strip, and then a layer of PLA solution was laid on the AZ91 strip. Next, the solvent was put in a drying oven at 100°C to evaporate for 6 h and produce a Mg-reinforced PLA-integrated membrane. The fabrication method of the integrated membrane in the control group is the same as above, except that the magnesium strip was replaced by a PLA strip. The average thickness of the integrated membranes was 120 μm. The integrated membranes were cut into the desired dimensions (Figure 1).

Polylactic acid (PLA) granules with a nominal size of 3–5 mm, a melting point of around 170 °C, and an average molecular weight of approximately 68,000 g/mol, were purchased from Goodfellow Cambridge Limited (Cambridge, England). Mg alloy (AZ61, purity 99.95%) powder with an average diameter of 100 μm was provided by Nanografi Nanotechnology (Ankara, Turkey). Chloroform (boiling point: 59.5–60.5 °C, density: 1.48 kg/L) was used as a PLA solvent supplied by VWR Chemicals, Darmstadt, Germany.