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With consumer demand reaching record levels and manufacturers ramping production to keep up, there has never been a greater need for packaging, which accounts for created worldwide. Unfortunately, only 9% of it is recycled. Where does the rest of it go? Some ends up in waterways, while most goes to landfills, where it takes hundreds of years to degrade. As companies evaluate how to improve the sustainability of their packaging portfolio, ideas about compostable packaging and biodegradable packaging have emerged.

In 91社区's 2022 sustainable packaging trends survey of 186 packaging decision-makers at consumer packaged goods companies (CPGs), 48% of respondents said they are adopting or evaluating the use of biodegradable or compostable materials for their programs; 42% said incorporating these materials are their highest sustainable packaging priority.

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To many in the packaging industry — and consumers as well — the concepts of compostability, biodegradability and bioplastics seem interchangeable. Considering the overlaps in these concepts, this misconception is easy to make. But it is just that — an inaccuracy. And it's one that could hinder progress in the sustainable packaging space until the industry clearly understands the differences, strengths and challenges of each type of material.

To grasp the overlap between compostable, biodegradable and bioplastic materials and how each could work in product packaging, it helps to think about the ideas in terms of two separate, but related, sustainability conversations: resource management vs. waste management. Where is your material coming from, and where is it going?

Sustainable Resource Management

The first material stream to know as part of the sustainable packaging conversation is sustainable resource management. This concept centers around caring about where your polymer originated. Materials could be plant-based (more commonly called bio-based), petrochemical-based or made from recycled materials.

Petrochemical-based plastics are traditional plastics made from either petroleum or natural gas. on earth, making it a large driver of the world's fossil fuels. Some of the most common plastics, like polyethylene terephthalate (PET) and high-density polyethylene (HDPE) can sometimes be recycled, but others, like the low-density polyethylene (LDPE) used for bread bags and film plastic, are rarely commercially recycled and may go to a landfill after just one use.

Bioplastics are made from renewable sources such as sugars, starches, cellulose or acids. These are typically derived from soybeans, corn, algae or wood. The most common bioplastic is polylactic acid, or , made from corn-derived lactic acid. Its rigidity and ability to stand higher temperatures make PLA a good replacement for common plastics like PET and HDPE.

Starch-based polyhydroxyalkanoates, or , is the next-most popular. Made from starches like corn or potatoes or canola, it is typically more flexible than PLA. Polybutylene adipate terephthalate, or , is also growing in popularity thanks to its elastic properties that work well as a replacement for film plastics.

There are several environmental advantages to using bio-based materials. Products made with biodegradable bioplastics decompose more quickly than the more widely used PET-based plastics. Bioplastics can also emit fewer greenhouse gases; according to a 2021 article, the precise emission reduction can vary wildly depending on when, where and how a particular bioplastic is produced. But the authors point to one peer-reviewed example of the company NatureWork's production of PLA, which was found to produce 60-80% fewer emissions than a comparable petrochemical-based plastic.

While the carbon absorbed by a bioplastic's feedstock as it grows can help offset some of the emissions created during its production, it is often not enough. Depending on the type of feedstock crop and how it was harvested and transported, the can be even higher than a traditional petrochemical-based plastic, according to a 2021 study out of the U.K.'s University of Sheffield.

Bioplastics may also, though not always, give companies the added benefit of compostability or biodegradability. A persistent misconception in the packaging industry is that bioplastics, compostable packaging and biodegradable packaging are inherently one and the same. This is not the case, although companies are using some bioplastics to create compostable and biodegradable packaging.

More than half (52%) of our 2022 sustainable packaging survey respondents said compostable resins play a significant role in their sustainable packaging strategy, while 44% said bio-based resins are important to the portfolio. As we will discuss, certain resins — depending on their composition — could fall into both categories.

While bioplastics are an issue of resource management, compostability and biodegradability are issues of waste, or end-of-life, management.

Material Stream 2: Sustainable Waste Management

The second material stream to consider as part of the sustainable packaging conversation is sustainable waste management. This concept focuses on where materials wind up at the end of their lives, after packaging can no longer be recycled or reused. The two main streams of sustainable waste management we'll focus on are the two methods of returning materials back to the earth: composting and biodegradation.

Materials that are compostable break down naturally over time using a blend of fungi, bacteria, insects, worms and other organisms to create a nutritious soil that fertilizes the earth. As such, more than half (52%) of survey respondents said compostable packaging has the potential to have a high degree of positive impact on the environment.

There are two types of compostable materials that require slightly different methods to yield the same result: home compostable and industrial compostable. Materials that are home compostable break down more easily and faster. They can be kept in a specific bin as they break down into nutrient-rich soil alongside organic materials like food scraps, grass clippings and hair, which can help speed up the breakdown. They must be able to compost in typical, ambient temperatures in a normal bacterial environment — meaning, without any added microorganisms.

For packaging to be labeled home compostable, over 90% of the components of the package — from the inks to the adhesives — must be able to completely break down in a home compost bin. The main international certification for home compostable packaging is the certification from TUV Austria, and it is the basis for Australian, French and European home compostability standards. Currently, there is no U.S. equivalent from the American Society for Testing and Materials (ASTM) or Biodegradable Products Institute (BPI), making the TUV certification the global industry standard. Home compostable materials must disintegrate (physical breakdown) within six months and biodegrade (chemical breakdown) to form compost within a year.

Industrial compostable materials need more time and more specific conditions to completely break down. Industrial composting facilities use chippers and grinders to begin the breakdown of materials, maintain optimal temperature levels, and alter the amount of air, carbon and nitrogen in the soil to help decompose materials that would be too difficult to compost in the home setting (like meat, fish and certain plastics).

Industrial compostable materials must disintegrate and produce compost within 180 days, and the resulting matter must be nontoxic to the environment. In the U.S., the certifies industrial compostable products that meet the ASTM's D6400 or D6868 requirement. The comparable standards in Europe and beyond are and . Logos on packaging from any of these organizations indicate the ability to be composted in an industrial facility. All materials that are home compostable are automatically industrial compostable, but not vice versa. Because home compost is less controlled than industrial compost, "home compostable" is a higher bar to clear, making resins that meet that requirement more engineering intensive.

It is even more difficult for materials to biodegrade. Unlike compostable materials, biodegradable materials simply break down into materials that can coexist with soil or water without the intervention of bacteria or worms. They do not require any outside intervention to biodegrade.

There are two types of biodegradable materials: landfill and marine. In both of these environments, materials cannot become compost, either due to a lack of oxygen (landfill) or the water environment (marine).

Landfill biodegradable materials must be able to biodegrade anaerobically, or without oxygen. There is no certification for landfill biodegradability, but materials that pass the test are generally accepted as a "certified" landfill-biodegradable material.

Marine biodegradability is the most challenging certification to receive. Materials must pass the test in the U.S. and the test internationally, while TUV Austria provides the certification. These materials must physically break down in three months and biodegrade in six months.

There is, indeed, a "hierarchy" of biodegradability. The more oxygen-rich the environment is, the easier it is for a package to naturally break down. Industrial or home composting affords the cleanest decomposition due to the controlled nature of the environment and the large number of bacteria that can surround and degrade the polymer. The lack of suitable bacteria in marine water makes it the most difficult condition for plastics to degrade.

Bioplastics, Compostable, Biodegradable: How Do they Overlap?

One common myth in sustainable packaging is that all bioplastics are inherently compostable or biodegradable. The term "biodegradable" is so loose and unregulated that the state of on products or in marketing. Only products that have been certified home or industrial compostable by the ASTM can make claims about their ability to break down.

While it is true that the polymers that make up bioplastics like PLA and PHA are biodegradable, final products — meaning the packaging made from bioplastics — have been highly engineered to meet a consumer's needs for barrier protection, tensile strength and more. In the engineering process, the biodegradability is sometimes engineered out — even within different grades of the same polymer family or different form factors.

However, biodegradability or compostability can be engineered back in. For example, most PLA is industrially compostable. For manufacturers, engineering bioplastics to be compostable or biodegradable must be a requirement of packaging to ensure it can be returned to the earth through compost or landfill biodegrading; you cannot assume packaging made from bioplastics can automatically be tossed in the compost bin.

Similarly, there is often a belief that recycling is the only sustainable end-of-life option for petrochemical-based plastics. They too can be engineered to be compostable or biodegradable.

As part of their sustainable packaging strategy, companies must ask themselves a few questions:

• How do I want to source my packaging materials?
• What do I want to happen with my packaging materials after consumers finish using them?
• Considering I can only choose one of the following options, would recycling, composting or biodegrading work best for my packaging?

From there, brands can work with materials science partners to create the packaging that works for their needs. For example, at 91社区 Materials Innovation Center, an all-inclusive beaker to box manufacturing facility for polymeric materials, we can formulate sustainable polymers for a customer's precise applications, testing them to ensure they perform exactly as needed for your packaging.

Armed with a better understanding of bioplastics and compostable and biodegradable materials, consumer packaged goods (CPG) brands might have one final question: How do I choose the right sustainable packaging for my product?

Which Packaging Applications Work Best with Compostability or Biodegradability?

Degradable polymers like to... well, degrade. Compostable materials need water and oxygen to subsume them so that they start to degrade and decompose. That is the opposite effect of packaging, which is intended to prevent oxygen and water from mingling with the product inside.

The principles that create a strong shelf life and a stable product are the exact reverse of those that create a great biodegradable or compostable product. For brands developing compostable packaging, managing those opposing forces is key to the innovation happening in the sustainable packaging space.

Generally speaking, there are a few applications where compostable packaging should be considered:

• When a reusable design is not feasible
• When the product cannot be readily recycled
• Products contaminated with food waste or that will end up in organic waste collection
• When there is infrastructure and regulation available for waste management of compostable materials
• When a product can have a shorter shelf life

When considering compostable packaging, brands could consider how realistic the "standard" shelf life used in packaging development is when compared with actual consumer behavior.

For example, say the "standard" shelf life of a coffee pod used to develop packaging is two years — thus preventing the use of compostable packaging. If the average coffee pod is actually used within six months, it might be worth exploring if a product needs to have a years-long shelf life if that means sacrificing compostability. The 91社区 survey indicates brands may already be thinking this way; nearly one-third (32%) of respondents said they would consider a slightly lower level of product protection in order to gain sustainability advantages, up from 19% in 2019.

Brands are certainly interested in compostable packaging; overall, 95% said it would be "definitely" or "likely" possible for their company to effectively implement compostable packaging. Almost a quarter of our 2022 survey respondents (23%) said they believe it could be the ultimate solution to sustainable packaging. Food and beverage (34%) companies showed the most preference for compostable solutions.

The year 2021 was a major one for food brands taking strides toward the adoption of compostable packaging. In March, announced its partnership with Danimer Scientific, a developer and manufacturer of biodegradable materials, to launch compostable packaging made from soy- and canola-based Nodax PHA for Skittle in the U.S. The candy company is currently piloting industrial compostable in select U.S. markets.

Snack brand Frito-Lay has also introduced an industrial compostable bag for two varieties of its -branded snacks. This packaging is made from 85% PLA and 15% petrochemical-based material. Frito-Lay estimates that raw material production for these new bags produces 60% fewer greenhouse gas emissions than a traditional plastic snack bag.

Once brands have implemented compostable or biodegradable packaging, the next step to creating a circular economy is educating consumers. Having clear and easy-to-digest disposal instructions for the consumer on product packaging is a great first step — for example, "Don't throw me away, compost me" or "Put in the compost bin, not the recycling." Keeping compostable PLA and PHA plastics out of the recycling streams is particularly important, as they will just be redirected to a landfill (instead of composted) when they reach a material recycling facility. They cannot be recycled alongside PET and HDPE plastics.

As a packaging industry, it's important that all stakeholders — from suppliers down to CPGs educating consumers — take ownership of managing our resources and the end of their lifecycle. Too often, compostability, biodegradability and bioplastics are lumped together into one eco-friendly, "green" story that lacks nuance and does little to advance sustainability efforts.

Without clear direction from brands about the proper disposal of their products, consumers who think they are making an environmentally conscious decision might be doing more harm than good. Improperly disposed biodegradable or compostable plastics can still pose a physical and chemical risk to the environment. But with the proper knowledge and support from materials science, it's possible to source your materials from the earth and return it back to the earth once the product's time has come to an end — creating a truly circular economy.