*2.4. The Microstructures of the Samples*

The scanning electron microscopy (SEM, AIS 2100, Uiwang-si, Korea) was applied to assess the microstructure of samples and also the surface of samples during the degradation period was observed to check if any changes occurred. It is important to notice that the micrographs were taken from the samples' surfaces before and after landfilling. In the case

of landfilled samples, after removing the soil, they were rinsed carefully and dried in a vacuum oven at 60 ◦C. The experiment was performed on the samples after the sixth week.


**Table 1.** Composition of PLA/Starch/PEG samples.
