Biodegradable Plastics

The purpose of this experiment was to determine whether Polylactic acid plastics biodegrade faster than Polyester based petroleum plastics. Polylactic acid plastics are sugar based and therefore should degrade relatively quickly in compost conditions.

To conduct this experiment, Werthman-Gladstone obtained samples of each type of plastic. They placed these samples in varying systems of soil, and moisture for four weeks and observed the percent of mass lost in each sample. Although Gladstone-Werthman's specific hypothesis (that the best conditions for biodegration would be PLA with moist compost) was proven incorrect, the PLA samples did have a higher average percent loss than the Polyester samples. The highest percent loss of .2010% occurred with PLA, in topsoil, and with 50 ml of water weekly.

Research Done By:

Carl Gladstone
East Detroit High School

Alyssa Werthman
L'Anse Creuse High School