Long before extreme weather events like the devastating hurricanes that ravaged large portions of the southern United States and South East Asia. Long before “Wildfires from Hell” consumed entire cities in California, persistent plastics floating in the oceans or found in the bellies of hapless marine birds, mammals and fish were the poster child for revealing the damage humans were doing to the planet.  Now as another wave of public awareness of climate change and the role we play in the process has returned with the recent focus on the need for a “Green New Deal”, it’s appropriate to revisit how plastics have undergone and continue to undergo transformation in response to the challenges climate change and sustainability present us today. 

After the general public became more aware of the chemicals used to manufacture plastics, they use in daily life, and their adverse effects on the environment, chemists, biologists, environmentalists, and other green technology and sustainability champions stepped up with an answer- bioplastics. These are environmentally friendly alternatives to fossil-based synthetic polymers that promised to provide products which were just as useful and durable as those they will replace, but would also be less problematic during manufacture, less toxic in use and even less persistent in the environment post-use. The argument being that the biological origin of these plastics makes them safer for living things and will be readily decomposed by natural processes quickly after disposal, effectively recycling their components back into nature.  Bioplastics as we know them today were born.

With the adoption and acceptance of bioplastics becoming mainstream, terms like "bio-based," "biodegradable," "biocompatible" and "compostable" have increasingly become attractive words to have on product labels. Manufacturers wanting to convince users it is worth paying extra dollars for their plastics have used these terms due to their perceived benefits to the environment. As someone involved in sustainable technology development and green chemical manufacturing, I admit they do help get the message across that a product should be preferred over it’s often cheaper fossil-derived competition.

However, as the figure below shows, the classification of bioplastics can be somewhat confusing. For instance, you have some bioplastics manufactured from fossil-derived polymers, and interestingly not all bioplastics are biodegradable!

 

 

 

It's not difficult to see that without a clear understanding of what these “green plastic” terms actually mean, many consumers and even plastics and polymer manufacturers can easily mislabel their products (unintentionally one would hope) ultimately bestowing unwarranted “green credentials” to the wrong product.  Thankfully there are industry-wide standards and norms that have been developed over time to address issues like this. The EN 13432 standard outlines various tests that plastic materials must meet before they can lay claim to these sustainability badges.  Below are a set of explanations in layman terms to describe what each word means and give you an idea of what makes a bioplastic “bio-based," "biodegradable," "bio-compatible" or "compostable." 

Bio-based:  A bioplastic is considered bio-based if at least some percentage of the building block monomers used in its production is from renewable origins. Here the emphasis is on the “age” of the carbon atoms contained in the plastic tested through C-14 isotope dating. (EN 16640 and or EN 16785)

Biodegradable:  For a bioplastic to be biodegradable, 90% of its carbon is metabolized (completely broken down by microbes)within 180 days when allowed to decompose with another biowaste under standard conditions (EN 14046)

Compostable:  Bioplastics are “compostable” if no more than 10% of the starting material remains after passing through a sieve of 2 mm pore size upon three months of composting along with biowaste using a standard composting technique (EN 14045)

Bio-compatible: refers to a plastic material which using standardized methods for assessing the ecotoxicity of the (plastic) material, must not feature any negative impact on living organisms or the involved environment. (ISO 10993)

Bioplastics comprise an entire family of materials with various properties and applications but generally, they are bio-based or biodegradable or both. Among other benefits, they have shown the potential to reduce carbon footprints through their lifecycles. They increase resource efficiency by enabling feedstock diversification and a move away from fossil-derived feedstocks while providing more sustainable disposal options at their end of life and many of the newly developed materials have shown just as good or even better mechanical and physical properties as the conventional plastics they replace.

Even as adoption of bioplastics continue and they become more and more part of our everyday lives, education about the nuances between the various types and their implication can only be positives for us as a society. The development of bioplastics in general and the creation of standardized methods to determine how their sustainability properties are defined provide an excellent illustration of the slow but steady transformation of an industry towards increased environmental awareness. Bioplastics development provide a template model for transforming other sectors that have an outsized impact on climate change to ensure our march towards a sustainability powered society keeps moving on the right track.

References
https://docs.european-bioplastics.org/publications/EUBP_Facts_and_figures.pdf
https://docs.european-bioplastics.org/publications/bp/EUBP_BP_En_13432.pdf

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