Life cycle assessments of biodegradable, commercial biopolymers—A critical review

• Published in: Resources, conservation and recycling conservation and recycling, 2013-09, Vol.78, p.54-66
• Main Authors: Yates, Madeleine R., Barlow, Claire Y.
• Format: Article
• Language: English
• Subjects: Applied sciences; biodegradability; Biopolymer; biopolymers; energy; environmental impact; Exact sciences and technology; farming systems; feedstocks; Global environmental pollution; global warming; Life cycle assessment; Pollution; Polyhydroxyalkanoate; Polylactic acid; polymers; recycling; Starch based polymers
• ISSN: 0921-3449; 1879-0658
• DOI: 10.1016/j.resconrec.2013.06.010

•LCAs comparing PLA, PHA, and starch-based biopolymers to conventional polymers have been reviewed.•Study results differ widely depending on assumptions made and the proposed application of the materials.•Biopolymers may offer greenhouse gas and fossil fuel savings in some situations.•Environmental impacts in other categories are often higher for biopolymers in comparison to some petrochemical plastics.•Future improvements are expected to improve the environmental profile of biopolymers. Biopolymers are generally considered an eco-friendly alternative to petrochemical polymers due to the renewable feedstock used to produce them and their biodegradability. However, the farming practices used to grow these feedstocks often carry significant environmental burdens, and the production energy can be higher than for petrochemical polymers. Life cycle assessments (LCAs) are available in the literature, which make comparisons between biopolymers and various petrochemical polymers, however the results can be very disparate. This review has therefore been undertaken, focusing on three biodegradable biopolymers, poly(lactic acid) (PLA), poly(hydroxyalkanoates) (PHAs), and starch-based polymers, in an attempt to determine the environmental impact of each in comparison to petrochemical polymers. Reasons are explored for the discrepancies between these published LCAs. The majority of studies focused only on the consumption of non-renewable energy and global warming potential and often found these biopolymers to be superior to petrochemically derived polymers. In contrast, studies which considered other environmental impact categories as well as those which were regional or product specific often found that this conclusion could not be drawn. Despite some unfavorable results for these biopolymers, the immature nature of these technologies needs to be taken into account as future optimization and improvements in process efficiencies are expected.