Open Access
ARTICLE
Depolymerization of Post-Consumer Polylactic Acid Products
David Grewell1,*, Gowrishankar Srinivasan1, Eric Cochran2
1
Department of Agricultural and Biosystems Engineering, Iowa State University, Ames, Iowa 50011
2
Department of Chemical and Biological Engineering, Iowa State University, Ames, Iowa 50011
* Corresponding Author:
Journal of Renewable Materials 2014, 2(3), 157-165. https://doi.org/10.7569/JRM.2014.634112
Received 12 January 2014; Accepted 05 June 2014;
Abstract
Presented in this study is a novel recycling strategy for poly(lactic acid) (PLA) in which the depolymerization
is rapidly promoted by the base-catalyzed hydrol-/alcohol-ysis of the terminal ester bonds under mild
conditions. Post-consumer PLA water bottles were cut into approximately 6 x 2 mm plastic chips and heated
to 50–60o
C in water, ethanol, or methanol as the depolymerization medium. A variety of carbonate salts and
alkaline metal oxides were screened as potential catalysts. High-power ultrasound was also investigated as
a means to accelerate the PLA decomposition. Both mass loss and HPLC analysis of the treated suspensions
showed that the conversion of PLA to lactic acid/lactic esters was achieved with yields over 90% utilizing
either ultrasonics or a hot bath. It was found that the most rapid decomposition occurred in solution of
sodium hydroxide in methanol at 50o
C, in which maximum depolymerization was complete in 5 min. It was
also seen that the degree of crystallinity affected the rate of depolymerization.
Keywords
Cite This Article
Grewell, D., Srinivasan, G., Cochran, E. (2014). Depolymerization of Post-Consumer Polylactic Acid Products.
Journal of Renewable Materials, 2(3), 157–165. https://doi.org/10.7569/JRM.2014.634112