2023 AIChE Annual Meeting
Impact of Degradation PEO-b-PCL on Aqueous pH
Plastics are made up of long chains of repeated structures, called polymers. These polymers can have unique characteristics especially when combined into copolymers which have characteristics of two or more polymers. Polyethylene-block-Polycaprolactone (PEO-b-PCL) is one such copolyester that demonstrates both hydrophilic and hydrophobic characteristics respectively. The amphiphilic nature of PEO-b-PCL makes it an ideal candidate for sustained drug delivery, especially with hydrophobic drugs. The polycaprolactone (within PEO-b-PCL) is a class of polymers called polyesters, that are known to release carboxylic acid when they degrade in water. Through this research, it has been found that the carboxylic acid, specifically caproic acid, produced by PCL degradation in water decreases the overall pH of its environment. Previously, degradation studies were conducted with clean DI water after each time trial with the previous DI water being thrown away. The main objective for past degradation studies were to examine the speed of degradation instead of degradation effects on its environment. This study showed how the PEO interacted with the caproic acid production of PCL. While there was an initial decrease in pH, the PEO seemed to create micelles that surrounded the caproic acid either increasing the pH or maintaining it, until the micelles degraded. The plateau shows a brief stability before pH continues to decrease compared to just PCL. Different areas of the body maintain constant pHs for maximum efficiency, thus maintaining that pH is important. This research gave insight to the safety of using the copolymer in the body or a marine environment.