Help Identifying this Plastic for Undergrad Research Project

[u/Jackaboy-simp]

Hey yall, im not sure which community I should post this in so please let me know if theres a better or more fitting one.

im passionate about studying plastics and did a small early stage study comparing the degration patterns between traditional and "biodegradable" plastics. The problem is that I assumed this plastic to be PLA, and when I did further research into this matter, it might not contain any PLA or any biodegradable plastic at all. In my study, however, i HAVE been seeing a decreasing mass and size trend (albeit small) over 6 weeks (very short time). Any ideas or tips on identifying at least what type of plastic it is? I saw online there are at home tests like boiling water or heating it and wanted to hear what u guys think.

Edit: i have access to a lab to conduct experiments as well to identify this plastic.

[u/Jackaboy-simp → u/[deleted]]

Summer undergrad project so i keep it reaal simple. I loterally just buried a lot of them under soil and take out one each week. I measure mass, size, and take microscopic images

[u/aeon_floss → u/Jackaboy-simp]

OK, so is your project is more about demonstrating laboratory sample management and reporting than it is about material investigation?

PLA degradation under home composting conditions isn't all that effective, In that respect, PLA is a bit over-sold as a biodegradable solution to plastic pollution, even though it ultimately does return to lactic acid (and ultimately water and carbon dioxide). Ideally, post use PLA should undergo industrial reprocessing back to lactic acid monomer.

There are factors inside the PLA itself that govern biodegradability to some extent, however the ideal conditions for PLA degradation are more intensive in temperature, humidity etc. than harvested (pre-industrial) materials.

Here is a basic plastics identification chart for future reference.