In a critical review published on July 21, 2021, in the International Journal of Environmental Research and Public Health, Diogo A. Ferreira-Filipe and co-authors from the University of Aveiro, Portugal, discussed the production of biobased plastics as well as their potential for recycling, environmental safety, toxicity, and biodegradation. The article gives an overview of the individual biobased polymers currently available on the market as well as the pros and cons of biobased plastics in general before outlining emerging solution options.
Potential advantages of biobased plastics, according to the authors, are their lower dependence on crude oil while they can also reduce greenhouse gas emissions. However, their production process may even be associated with higher greenhouse gas emissions than that of petroleum-based plastics, the authors note. This is the case for woody feedstocks since biorefining processes are required. At the same time, current production of biobased plastics is energy-intensive. The authors highlighted that some biobased polymers can have more attractive properties than their fossil-based counterparts. For instance, polyethylene furanoate (PEF) has a reduced oxygen and carbon dioxide permeability than polyethylene terephthalate (PET). However, to offset limitation often inherent to biobased materials, and to increase their functionality, even more chemicals may be added to biobased than petroleum-based polymers. Thus, biobased products do not necessarily outperform their counterparts in ecotoxicological nor toxicological impacts (FPF reported). Concerning end-of-life options, the commentary makes clear that biodegradation, even of certified “biodegradable” plastics, is limited to specific conditions, e.g., conditions only occuring in industrial composting facilities. When combined with the branding of biobased plastics as “green,” consumers can form misconceptions around disposal which may result in increased littering.
Although comprehensive policy regulating biobased or biodegradable plastics is lacking, biobased plastics are a component of existing policy frameworks like the EU plastics strategy (FPF reported) and the European Green Deal (FPF reported). Though under the single-use plastics directive biobased single-use products are considered the same as conventional plastic products (FPF reported).
Ferreira-Filipe and colleagues emphasized that legislative and regulatory action is needed to incentivize research and investment to allow these comparably new materials to catch up to the well-established petroleum-based plastics. Proposed options to improve functionality and properties of biobased materials are to include nanocomposites in the polymerization process or choosing algae as feedstock. The ecological impact could further be reduced by using waste from food, agro-, or forest industries to produce biobased products. Moreover, the authors laid out that rules are needed to “incentivize manufacturers to integrate environmental performance in the development of new polymers” as well as to expand toxicity testing. For instance, international standards for biodegradable and compostable plastics should also cover effect assessments on the biochemical and community level, as well as on ecosystem functioning. The authors of the commentary see regulatory authorities responsible for demanding clear labeling that familiarizes consumers with the concept of biobased plastics and their proper disposal. Regulatory frameworks should further support the adaptation of existing recycling schemes to accommodate these new materials. For instance, it has to be ensured that even though they appear similar, biobased plastics such as polylactic acid (PLA) do not end up in recycling streams for PET because this contamination would lead to recycled PET of poor quality.
The authors conclude that biobased plastics have a high potential to support a transition to a sustainable, circular, and low-carbon plastic economy but that the industry for these materials “must be scaled up responsibly, always considering the economic, legislative, and social sides of this equation so that it may have the opportunity of truly fulfilling its perceived potential.”
Several reviews published in April and May 2021 focused on the currently accepted terminology of biobased polymers and touched upon the supply chain and particular traits of these polymers (FPF reported).
Ferreira-Filipe, D. A., et al. (2021). “Are Biobased Plastics Green Alternatives?-A Critical Review.” International Journal of Environmental Research and Public Health. DOI: 10.3390/ijerph18157729