The Effects of pH on Biodegradable PLA Plastic

Abstract

The focus of this study was to observe how polylactic acid (PLA) degradation is affected by varying pH environments. To test this, straw segments were submerged in 3 different pH conditions (pH 4, 7, and 10). The experiment lasted 10 days and mass was measured as a metric of how much the PLA straws degraded into the solution. The initial mass of the straws were measured prior to being submerged in buffer solutions, and recorded again after 1, 7 and 10 days, while photos were taken throughout to record observable reaction rate. Based on previous research, if the straw segments submerged in pH solutions 4-10, the more basic solutions will dissolve more and have a lower mass by day 10. For measuring the mass, the segments were taken out of the tubes and dried in an oven for 24 hours before weighing to get the most accurate readings. As the experiment continued the pH levels were also measured and there was no significant change between each measuring day. The weight of the day 10 segments varied from the initial mass but was not significant enough to accept our hypothesis.