Title: Temperature-dependent polylactic acid (PLA) anaerobic biodegradability

Authors: Bo Shi; Doris Palfery

Addresses: Environmentally Sustainable Technology, Kimberly-Clark Corporation, 2100 Winchester Road, Neenah WI 54956, USA ' Environmentally Sustainable Technology, Kimberly-Clark Corporation, 2100 Winchester Road, Neenah WI 54956, USA

Abstract: Polylactic acid (PLA) biodegradability is mostly claimed according to PLA biodegradation behaviour under aerobic composting conditions. However, waste materials containing PLA are frequently disposed of in municipal landfills, which are operated anaerobically. PLA anaerobic sludge digestion results are acquired to elucidate effects of the degrading temperature on PLA biodegradation. When the degrading temperature is higher than the PLA glass transition temperature (T_g), anaerobic biodegradation is accelerated. A plausible mechanism to explain this observation is that amorphous part of the polymer is easily accessible by microorganisms. When the degrading temperature is below PLA T_g, anaerobic biodegradation is apparently slowed. PLA anaerobic biodegradation data collected at 50 and 65°C were successfully modelled using the first order kinetic equation.

Keywords: polylactic acid; PLA biodegradability; glass transition temperature; municipal landfill; anaerobic biodegradation; aerobic composting; sludge; modelling; municipal solid waste; MSW; waste management.

DOI: 10.1504/IJEWM.2012.048324

International Journal of Environment and Waste Management, 2012 Vol.10 No.2/3, pp.297 - 306

Received: 07 Oct 2010
Accepted: 18 Jun 2011
Published online: 13 Dec 2014 *

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