Compostable plastics degradation temperatures

PLA is a compostable plastic material. Chemical hydrolysis is considered to be the main degradation route for PLA [14]. This hydrolysis process takes place at high humidity and at elevated temperatures (for example in industrial composting facilities). The fragments that result from the hydrolysis process, i.e., short oligomers and monomers, then can be metabolized by microorganisms. Therefore,... 

Summary This American specification standard establishes the performance requirements for biodegradation of compostable plastic materials that are designed to biodegrade into CO2, water, and biomass in an industrial compost environment. The industrial compost environment is one that maintains a temperature above 40° C and results in thermophilic conditions. The performance specification standard requires the use of ASTM D5338-05 test method to measure the amount of CO2 that is emitted from the degrading plastic sample. 

Ho, K.-L.G. and Pometto, A.L. Ill (1999) Temperature effects on soil mineralization of polylactic acid plastic in laboratory respirometers. Journal of Environmental Polymer Degradation, 1, 101-108. Buchanan, C.M., Dorschel, D.D., Gardner, R.M. et al. (1995) Biodegradation of cellulose esters Composting of cellulose ester-diluent mixture. Journal of Macromolecular Science, Part A Pure and Applied Chemistry, A32,683-697. 

The degradation of polylactic acid (PLA) plastic films in Costa Rica soil and in a leaf composting environment was investigated [22]. The average soil temperature and moisture content in Costa Rica were 27°C and 80%, respectively. The average degradation rate of PLA plastic films in the soil of the banana field was 7657 A/ /week. PLA films required two weeks to disintegrate physically in leaf compost rows. 

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