Biodegradable packaging life-cycle assessment

SRI Consulting's Process Economics Program (PEP) was commissioned by its clients to undertake a lifecycle assessment (LCA) for the purpose of comparing a biodegradable polymer with a conventional commodity polymer in packaging applications. Biodegradable polymers offer the potential of addressing a wide range of environmental concerns associated with conventional polymers such as greenhouse gas emissions and sustainability. LCA is a tool specifically developed for assessing the overall environmental burden of a product including the system used for manufacturing it and its end-of-life treatment. This paper provides a cradle-to-grave LCA of two polymers that may be used in food packaging applications: polylactide (PLA), which is a biodegradable polymer derived from corn; and polypropylene (PP), which is primarily derived from natural gas in the United States. An inventory analysis of the PLA and PP systems is presented. An impact assessment focused on global warming is also provided. Although measured field or facility data are preferred for a rigorous LCA, PEP data can provide a reasonable basis when measured data are unavailable. Energy inventories and greenhouse gas emissions are readily derived from PEP data, but other potentially relevant impact indicators are not. (C) 2004 American Institute of Chemical Engineers.