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ARS Home » Pacific West Area » Albany, California » Western Regional Research Center » Bioproducts Research » Research » Publications at this Location » Publication #376101
Research Project: Bioproducts and Biopolymers from Agricultural Feedstocks

Location: Bioproducts Research

Title: Evaluation of biodegradation of polylactic acid mineral composites in composting conditions

Author
item FLYNN, ALLISON - Former ARS Employee
item Torres, Lennard
item Hart-Cooper, William
item McCaffrey, Zachariah - Zach
item Glenn, Gregory - Greg
item Wood, Delilah - De
item Orts, William

Submitted to: Journal of Applied Polymer Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/14/2019
Publication Date: 3/2/2020
Citation: Flynn, A., Torres, L.F., Hart-Cooper, W.M., McCaffrey, Z., Glenn, G.M., Wood, D.F., Orts, W.J. 2020. Evaluation of biodegradation of polylactic acid mineral composites in composting conditions. Journal of Applied Polymer Science. 137(32). Article 48939. https://doi.org/10.1002/app.48939.
DOI: https://doi.org/10.1002/app.48939

Interpretive Summary: Overproduction of plastics is an increasing public concern due to the large amounts of waste plastics amassing in marine environments and accumulating as litter. A large portion of the waste is from single-use items in the form of packaging. Plant-based poly-lactic acid (PLA) is finding its way into single-use items which is a benefit over the use of petrochemical-based plastics. However PLA is difficult to biodegrade thus, even the plant-based plastics accumulate in the environment. The enhancement of the biodegradation rate of PLA filled with commercially available soil amendment product or a nanoclay was studied. The process could increase PLA degradation rate in industrial compost systems and thus decrease plastic accumulation in the environment.

Technical Abstract: In this study, the enhancement of the biodegradation rate of polylactic acid (PLA) filled with commercially available soil amendment product (NTM) or a nanoclay (Cloisite 25A) were evaluated. Cloisite 25A and NTM were incorporated into PLA at 5, 10, 20 (w/w) through melt blending. Transmission electron micrographs revealed particles with a wide range of sizes that were formed by clumping of many smaller particles. The particles showed good dispersion in PLA by scanning electron microscopy. Under standard composting conditions using a standard technique for aerobic biodegradation of plastic materials, it was shown that the addition of NTM enhanced the biodegradation rate of PLA composites by 3- to 4-fold compared to neat PLA. Linear kinetics were used to obtain induction periods, half-lives, and rates of mineralization. Finally, mechanical and thermomechanical properties of these blends were compared with PLA.