Plastic recycling is affected by plastic manufacturing, which relies on catalysts that, in small quantities, lower the energy required to string together simple building blocks referred to as monomers into a polymer (polymerization). Ethylene, propylene, glucose, and styrene are examples of monomers that create most polymers. Sid Perkins, Chemistry Explainer: What Are Polymers?, ScienceNewsExplores (Oct. 13, 2017). Polymerization transforms the monomers into a polymer with a different chemical profile than the original building block. For example, when styrene is polymerized into polystyrene, the thermoplastic polymer material can comply with food contact regulations, such as those adopted by the Food and Drug Administration at 21 C.F.R. Parts 175–179. In addition to chemical transformation, catalytic polymerization lowers the embodied energy of plastic in contrast to how other materials are fabricated, such as steel, glass, cement, and aluminum that generally require 2 to 10 times more energy to produce.
Polymer chain length, degree of polymer branching, and size of polymer branches can all influence a plastic’s properties and, hence, its possible applications. Small quantities of additives can expand the range of specific properties present in the final product. Examples of these properties include flexibility, UV stabilization, fire resistance, and color, as described by the Thomas Guide, Additive Effects in Polymers, at Thomasnet.com.
From this extensive array of molecular architectures and additives, formulators craft intentionally designed plastics to meet specified performance expectations. Consider a plastic trash bag designed to hold kitchen garbage: It rarely breaks, within reason. It has been intentionally designed to optimize the properties for this application. Other plastics, such as building joint sealant, keep us dry in the rain or are designed to last for decades. The intentional formulations balance the desired properties, including toughness, strength, elongation, water resistance, and, most important, durability. Elizabeth Atalay et al., Plastics Explained, from A to Z, Nat’l Geographic, May 17, 2018. Durability is a defining characteristic of single-use plastics as it determines a product’s shelf life. Except for durability, most plastic formulations have not considered the plastic life cycle post-use once a plastic has served its original purpose, the result being that most single-use plastics persist beyond their anticipated usage.
According to the U.S. Environmental Protection Agency (EPA), our society has overemphasized the promise of recycling while largely ignoring practical and effective reduce and reuse alternatives to address the accumulating post-use plastic waste. EPA, Draft National Strategy to Prevent Plastic Pollution, EPA 530-R-23-006 (Apr. 2023). Consumers have been guided to sort household waste using two symbols: the “chasing arrows” recycling logo and resin codes. The recycling symbol, created to coincide with the first Earth Day in 1970, reinforced the perception that plastic could be recycled into new plastic materials, removing the motivation to reduce or reuse. Tyler Farmer, A Look at the History of the Universal Recycling Symbol, Recycle Nation (May 4, 2011). However, while many different types of plastic (identified by resin code) may have the same physical appearance, their unique properties often make them incompatible when blended in a recycling process. To help prevent this incompatible blending, the resin identification code (RIC) system assigns a number from one to seven based on the base plastic (resin) inside the “chasing arrows” symbol. It does not ensure that the plastic is recycled, but rather that it is identified so that it can be sorted into similar base plastic groups, while the general categories include a “catchall” #7 that is not specific. The resin code does not capture the wide diversity of applications possible within a base chemistry. For example, resin code 3, polyvinyl chloride, includes single-use packaging, flexible plastic fishing worms, medical IV tubing, and single-ply roofing designed to last for decades. Nevertheless, there is a general perception that the base plastics that bear these resin codes can be or are recycled, which is contrary to reports that only about 9% of plastic waste is actually recycled. EPA, National Overview: Facts and Figures on Materials, Wastes and Recycling (Nov. 22, 2023).
With the perception that accumulating plastic waste was a managed issue, the implementation of reduce and reuse strategies was often done on an ad hoc basis, making it difficult to quantify their actual impact. As such, the efforts to reduce have largely stemmed from regulation. For example, nine states and hundreds of local governments ban the use of plastic bags, and hundreds of cities have instituted a plastic bag tax, which so far has enjoyed only limited success. Asphat Muposhi et al., Considerations, Benefits and Unintended Consequences of Banning Plastic Shopping Bags for Environmental Sustainability: A Systematic Literature Review, 40 Waste Mgmt. & Res. 248 (2022). Similar bans on single-use plastic cutlery, straws, and food containers have been implemented with mixed results. Annie Lowrey, The Case Against Paper Straws, The Atlantic, Aug. 20, 2019.
This approach to reducing plastic through bans or quotas is featured in the United Nations Environment Assembly Resolution 5/14 adopted on March 2, 2022, to “End Plastic Pollution,” with the goal of drafting an international legally binding agreement by 2024. This approach may have unintended consequences as the alternatives to plastic are generally less energy efficient. Norbert Sparrow, PET Bottles Have Smaller Environmental Impact Than Glass and Aluminum Containers, Study Shows, Plastics Today, Mar. 7, 2023.
While coordinated and targeted regulations may ultimately prove effective in reducing plastic usage, reusing plastic falls more under the purview of personal choice. Jefferson Hopewell et al., Plastics Recycling: Challenges and Opportunities, 364 Phil. Transactions of Royal Soc’y B, Biological Sci. 2115 (2009). A vast and varied collection of countless websites and social media outlets provide guidance and inspiration for people hoping to reuse their existing plastic through creative pursuits (arts and crafts), functional projects (furniture and structures), and practical repurposing (tools and gadgets).
The visibility of plastic waste accumulation increased in the United States after the implementation of China’s National Sword policy in 2018 and the addition of the nonconforming plastic waste amendments to the Basel Convention in 2021. The Basel Convention amendments prohibited Mexico, Canada, and other nations from accepting transnational shipments of plastic waste from the United States, further exacerbating the visibility of the accumulating plastic waste problem.
In response, several states have followed Europe’s lead and passed extended producer responsibility (EPR) laws. Steve Toloken, Viewpoint: This Is the Year the Reality of Plastics EPR Arrives in the US, Plastics News, Feb. 2, 2023. These regulations are designed to shift the responsibility for managing post-use plastic waste from the end user back to the producer. These regulations will come into effect shortly, yet many details have yet to be determined. For example, these regulations are focused on single-use packaging, yet can easily be expanded to include other plastic formulations or applications. These regulations focus on developing strategies to increase the volume of plastic materials recycled into new products. As Jefferson Hopewell and colleagues, supra, discuss, the EPR regulations are being simultaneously developed in several states with varying degrees of industrial input, though often without significant consideration of the technical aspects of plastic recycling and management.
In addition to the creation and expansion of EPR laws, other forces are also shaping this landscape. For example, in April 2022, the California Attorney General’s office initiated an investigation into the fossil fuel and petrochemical industries’ role in causing and exacerbating the global plastics accumulation crisis.
Additionally, consumers organized by social media are demanding rapid changes to plastics and plastic formulations. Global consumer and regulatory pressures have also resulted in several other changes, such as the banning of intentionally added microplastics and the removal of other additives. See, e.g., Commission Regulation 2023/2055 of Sept. 25, 2023, Amending Annex XVII to Regulation (EC) No 1907/2006 of the European Parliament and of the Council Concerning the Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH) as Regards Synthetic Polymer Microparticles, 2023 O.J. (L 238) 67.
So, is it possible to create incentives to encourage intentional formulations that consider design specifications and use limitations to mitigate aspects of concern for plastics such as microparticle shedding? Can such a redesign support recycling with transparent and simplified polymer and additive post-use mix, leading to better management for end-of-life products and more complete capture, recycling, and reuse?
To answer these questions, consider that 139 million tons of single-use plastic packaging were used last year. Minderoo Found., Plastic Waste Makers Index, 2021. Also 125 million tons of bananas were produced during the same time. Statista, Volume of Bananas Produced Worldwide, 2010–2021. Just like plastic packaging, the banana peel can also be called a single-use package. However, it not only begins its degradation journey once it completes its purpose, but it also has a finite shelf life. With the ingenuity of American industry, can the next generation of traditional single-use packaging materials be formulated to be more like banana peels? Published research demonstrates that it is possible. Quian Ying Lee & Hong Li, Photocatalytic Degradation of Plastic Waste: A Mini Review, 12 Micromachines 907 (2021). Efforts are also underway to commercialize bioplastics such as polylactic acid to realize this vision.
Presently, the existing processes and regulations dealing with plastic waste are changing. No consensus has emerged on plastic waste regulation. Examples of initiatives include the various EPR regulations that center on the recycling of plastic waste. Other initiatives are exploring different solutions, such as the European Single-Use Plastics Directive, the European Waste Framework Directive, Canada’s Zero Plastic Waste Agenda, and the United Nations treaty efforts on plastic pollution. These efforts are in various stages of development.
As this regulatory framework continues to evolve, there is a compelling case for expanding its scope to encompass a broader array of considerations. One promising avenue is the introduction of subcategories for intentionally designed plastics beyond the RIC codes discussed earlier. These subcategories could encompass packaging, durable plastics, and degradable plastics, among others. By differentiating between these categories, it becomes possible to tailor specific regulations and incentives that align with the unique characteristics and challenges posed by intentionally designed plastic formulations. This approach would not only encourage the reduction of plastic waste or reuse but also stimulate innovation in the design and production of plastics, ultimately fostering a more sustainable approach to plastic usage.
However, there is a delicate balance to be struck between preserving the essential functionality of plastics, which have become an integral part of modern life, and fostering innovative solutions to effectively address the mounting problem of post-use plastic waste. Finding this equilibrium is essential as we navigate the complex landscape of evolving plastic waste regulation.
