Understanding Agricultural Plastics: A Practical Guide to Plastics, Bioplastics, Microplastics and End-of-Life
Table of Contents
1. What Is Plastic?
2. Two Different Questions
3. Designing the End-of-Life
4. What Are Microplastics?
5. How Are Microplastics Formed?
6. Why Some Plastics Follow a Different End-of-Life Pathway
7. Understanding Certification Standards
8. Understanding Oxo-Degradable Plastics
9. Understanding PFAS
10. Conclusion
Glossary
References
Introduction
Why this guide exists
Plastic, bioplastic, bio-based, biodegradable, compostable, oxo-degradable, PFAS and microplastics are often discussed as if they meant the same thing. They do not.
This guide explains these concepts using plain language while remaining scientifically accurate. Its objective is not to promote a specific product, but to help growers, agronomists, researchers and policy makers better understand today's agricultural plastics.
1. WHAT IS PLASTIC?
Plastic Changed the World
Take a moment and look around you.
Whether you are at home, at work, on a farm, or in a laboratory, you are surrounded by plastics. From drinking water systems to medical devices, food packaging, greenhouses, automobiles and smartphones, plastics have become one of the most important families of materials ever developed.
Yet surprisingly, few people realize that plastic is not a material.
It is a broad family of materials with very different properties, applications and end-of-life characteristics.
Understanding that simple idea is the first step toward understanding bioplastics, biodegradability and microplastics.
Figure 1. The evolution of polymer design reflects changing engineering priorities. Early polymer innovations focused on performance, durability and manufacturability, whereas modern materials may also be designed with a specific end-of-life pathway in mind. This progression illustrates how end-of-life has become an additional engineering objective rather than a replacement for traditional performance requirements.
A Family of Materials
Just as the word metal includes steel, aluminum, copper and titanium, the word plastic includes hundreds of different polymers.
Each polymer was developed because it possesses unique physical and chemical properties that make it suitable for particular applications.
Some are rigid.
Some are flexible.
Some are transparent.
Some resist sunlight.
Some resist chemicals.
Some remain stable for decades.
Others are designed for much shorter service lives.
There is no such thing as "the plastic."
There are hundreds of different plastics.
Why Were So Many Plastics Developed?
Every time scientists and engineers developed a new polymer, they asked essentially the same questions.
Is it strong enough?
Is it light enough?
Is it flexible or rigid enough?
Can it withstand heat, sunlight or chemicals?
Can it be manufactured economically?
Will it last long enough for its intended application?
What products could this new material improve or even revolutionize?
These questions led to remarkable innovations throughout the twentieth century.
Polyethylene transformed packaging and agriculture.
Polypropylene enabled lightweight reusable products and strong synthetic fibers.
PET revolutionized beverage bottles.
PVC changed construction and water distribution.
Nylon transformed textiles and mechanical components.
Each new polymer opened the door to entirely new applications.
One Word... Hundreds of Materials
Today, we casually refer to all of these materials simply as plastic, even though they behave very differently.
A yogurt container.
A water bottle.
A fishing line.
A rope.
A greenhouse film.
An irrigation pipe.
A medical syringe.
A playground slide.
A biodegradable mulch film.
All are commonly called plastics.
Figure 3. Plastics are ubiquitous in modern society and are found in applications ranging from food packaging and healthcare to agriculture, recreation and infrastructure. Although these products differ greatly in composition, properties and intended use, they are all commonly referred to as "plastics."
Yet they are made from different polymers, designed for different purposes, and intended to perform under very different conditions.
This is why simply saying that something is plastic tells us very little.
To understand a plastic, we must ask better questions.
A New Question for the Twenty-First Century
For much of the twentieth century, engineers focused primarily on how materials would perform during their useful life.
That approach transformed modern society.
Today, however, one additional question has become increasingly important:
What should happen to this material once its useful life is over?
This question has not replaced the traditional design criteria.
It has simply become another design objective for certain applications.
The answer to that question has led scientists to develop new families of polymers designed not only for performance during use, but also for specific end-of-life pathways.
That is where our journey begins.
2. Two Different Questions
One Word, Two Different Meanings
One of the greatest sources of confusion surrounding plastics is the term bioplastic.
Many people assume that if a material is called a bioplastic, they already know everything they need to know.
In reality, they know almost nothing.
The word bioplastic can refer to two completely different characteristics.
The first concerns where the carbon comes from.
The second concerns what happens to the material after it has been used.
These are two independent questions.
Understanding the difference is essential.
Question 1
Where Does the Carbon Come From?
Some plastics are produced primarily from fossil resources such as petroleum or natural gas.
Others are produced partly or entirely from renewable biological resources such as corn, sugarcane, vegetable oils or other forms of biomass.
This characteristic is known as bio-based content.
It simply describes the origin of the carbon atoms used to manufacture the polymer.
It does not describe how the material behaves after use.
Question 2
What Happens at the End of Its Useful Life?
A completely different question concerns the material's intended end-of-life.
Depending on its design, a plastic may be intended to:
remain durable for decades;
be mechanically recycled;
be chemically recycled;
be industrially composted;
biodegrade under specific environmental conditions;
or follow another managed end-of-life pathway.
These characteristics are determined by the chemistry of the polymer, the product design and, in many cases, by recognized certification standards.
The origin of the carbon alone does not predict the material's end-of-life behaviour.
Two Independent Characteristics
Because these two questions are independent, several combinations are possible.
The relationship between bio-based content and biodegradability is often misunderstood. The following figure illustrates why these two characteristics should be considered independently.
Figure 2. A material can be classified using two independent characteristics: the origin of its carbon (fossil-based or bio-based) and its intended end-of-life pathway (non-biodegradable or biodegradable). The term bioplastic refers to materials that are bio-based, biodegradable, or both.
Each combination exists today.
This is why the word bioplastic, by itself, does not provide enough information to understand a material.
3. Designing the End-of-Life
A New Design Challenge
Throughout the twentieth century, plastics transformed nearly every aspect of modern life.
Engineers continuously developed new polymers to improve strength, flexibility, durability, weight, manufacturability and cost.
These innovations changed medicine, agriculture, transportation, construction, food preservation and countless other industries.
For many applications, durability was one of the greatest achievements of polymer science.
The longer a material lasted, the greater its value.
When Durability Became a Question
As plastic use expanded into thousands of new applications, society began asking a new question.
Not every product is intended to last for decades.
Some products are designed to be used for only a few minutes.
Others for a few days.
Some for a single growing season.
Others for only a few years.
If a product is intentionally temporary...
Should the material from which it is made also remain in the environment indefinitely?
This question marked an important evolution in material science.
A New Design Objective
The challenge was no longer simply to design materials that performed well during use.
Scientists began asking whether certain materials could also be designed to follow a specific end-of-life pathway once their job had been completed.
In other words...
Could a material be engineered to deliver the required performance and then transition responsibly at the end of its useful life?
For some applications, the answer became yes.
The Right Material for the Right Application
This does not mean that every material should biodegrade.
In many applications, long-term durability remains essential.
Water distribution pipes.
Medical equipment.
Automobile components.
Electrical insulation.
Building materials.
These products are expected to perform reliably for many years.
Their durability is precisely what makes them valuable.
However, other applications present a different design challenge.
Agricultural mulch films.
Certain food-service products.
Organic waste collection bags.
Some types of packaging.
These products are intentionally used for a limited period before entering a managed end-of-life system.
For these applications, engineers began exploring polymers designed with different end-of-life characteristics.
Designing for Function... and for What Comes Next
Modern material design increasingly considers two phases of a product's existence.
During use
Will the material perform its intended function safely and effectively?
After use
What is the most appropriate destination for this material once its mission has been completed?
Depending on the application, that destination may involve reuse, recycling, composting, biodegradation or long-term durability.
There is no single correct answer.
The appropriate solution depends on the function of the product.
Evolution, Not Replacement
The emergence of biodegradable polymers does not represent the replacement of conventional plastics.
It represents the expansion of the material toolbox.
Just as new polymers were developed throughout the twentieth century to solve new engineering challenges, biodegradable polymers were developed to address specific applications where end-of-life became an important design consideration.
Rather than asking which material is universally "better," engineers increasingly ask a different question:
Which material is best suited for this particular application?
Looking Ahead
Once end-of-life became a design objective, scientists faced another challenge.
How could they demonstrate that a material truly biodegrades as intended?
How could governments, industries and consumers distinguish between marketing claims and scientifically verified performance?
Answering these questions required the development of internationally recognized testing methods and certification standards.
That is the next chapter.
4. What Are Microplastics?
Microplastics are defined by their size—not by the type of plastic they come from.
A Size Classification
The term microplastic does not describe a particular polymer.
It does not indicate where the material came from.
It does not describe whether the plastic was originally rigid or flexible.
Instead, the term refers only to particle size.
A microplastic is simply a small plastic particle measuring less than 5 millimetres in its largest dimension.
That particle may originate from polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), polyvinyl chloride (PVC), nylon (PA), polystyrene (PS), or many other polymers.
In other words, almost any plastic can become a microplastic if it fragments into sufficiently small particles.
Understanding Plastic Particle Sizes
Scientists generally classify plastic debris into four broad size categories.
Macroplastics
Greater than 25 mm
Examples include plastic bottles, bags, agricultural mulch films, fishing nets and other large plastic objects that remain easily visible.
Mesoplastics
Between 5 mm and 25 mm
These are smaller fragments that remain visible to the naked eye but are no longer considered large plastic debris.
Microplastics
Between approximately 1 µm and 5 mm
These particles are often invisible without close inspection and can be transported by wind, water and biological systems.
Most scientific studies define microplastics as particles smaller than 5 mm.
Nanoplastics
Smaller than approximately 1 µm
Nanoplastics are so small that they behave differently from larger particles.
They are an active area of scientific research because of their potential interactions with living cells and biological tissues.
Size Does Not Explain Behavior
Knowing that a particle is a microplastic tells us only one thing:
its size.
It does not tell us:
which polymer it is made from;
how it was created;
whether it is bio-based or fossil-based;
whether it is biodegradable;
whether it can be recycled;
how long it may persist in the environment.
Those questions require additional information about the material itself.
Why Size Matters
As plastic particles become smaller, their behavior changes.
Smaller particles can:
travel farther through air and water;
mix more easily with soils and sediments;
become more difficult to recover;
interact with a wider range of organisms.
For this reason, scientists often classify plastic pollution by particle size before studying its sources, movement and potential environmental impacts.
Looking Ahead
Knowing what a microplastic is naturally leads to the next question.
How are microplastics created?
Do plastics leave the factory as microplastics?
Or do they become microplastics over time?
Understanding the answer is essential to understanding plastic pollution.
5. How Are Microplastics Created?
Most microplastics are not intentionally manufactured. They are generally created when larger plastic objects gradually fragment into smaller particles.
Fragmentation Is Part of a Material's Life
Plastic products rarely become microplastics overnight.
Instead, fragmentation is usually a gradual process driven by repeated physical, mechanical and environmental stresses throughout a product's useful life or after it has been discarded.
The speed of fragmentation depends on many factors, including the polymer itself, product design, environmental conditions and how the product is used.
Everyday Sources of Fragmentation
Plastic fragmentation occurs all around us, often without being noticed.
Opening a Plastic Bottle
Every time a plastic bottle is opened and closed, friction occurs between the cap and the bottle neck.
Although the amount of material released is extremely small, repeated use gradually produces microscopic plastic particles.
Cutting Food on a Plastic Cutting Board
Repeated contact between a knife and the cutting board removes tiny fragments from the surface.
Over thousands of cuts, microscopic plastic particles are generated through simple mechanical wear.
Tire Wear
Automobile tires continuously lose material as they roll across road surfaces.
This abrasion is now recognized as one of the largest sources of microplastic emissions worldwide.
Unlike many plastic products, tire wear occurs during normal use rather than after disposal.
Washing Synthetic Clothing
Many modern textiles are made from synthetic polymers such as polyester, nylon or acrylic.
During washing, tiny fibers may detach from the fabric.
Some are captured by wastewater treatment systems, while others may eventually enter rivers, lakes and oceans.
Agricultural Plastic Films
Agricultural mulch films are exposed to sunlight, wind, soil particles, machinery and repeated handling during installation and removal.
These combined stresses can contribute to fragmentation, particularly when materials are not designed for the intended application or when they remain in the environment beyond their useful life.
Outdoor Weathering
Plastic products exposed outdoors experience continuous cycles of sunlight, oxygen, rain, temperature changes and mechanical stress.
Over time, these environmental factors may weaken the material and increase its susceptibility to fragmentation.
The Fragmentation Process
Although the sources differ, the mechanism is remarkably similar.
Large plastic object
↓
Mechanical or environmental stress
↓
Small fragments
↓
Microplastics
↓
Nanoplastics
Fragmentation is therefore best understood as a progressive reduction in particle size, rather than a single event.
Primary and Secondary Microplastics
Scientists distinguish between two broad categories.
Primary Microplastics
Particles intentionally manufactured at microscopic size for specific applications.
Examples historically included microbeads used in certain cosmetics and industrial products.
Secondary Microplastics
Particles produced by the fragmentation of larger plastic products during use, weathering or disposal.
Today, secondary microplastics are considered the dominant source of microplastic pollution in the environment.
An Important Distinction
Fragmentation and biodegradation are fundamentally different processes.
Fragmentation changes the size of a plastic particle.
Biodegradation changes the chemistry of the material itself through microbial activity.
Understanding this distinction is essential before discussing biodegradable polymers.
Looking Ahead
If fragmentation reduces plastics into increasingly smaller particles, an important scientific question naturally follows.
Can some polymers follow a different end-of-life pathway instead of continuing to fragment?
To answer that question, we must first understand what scientists mean by biodegradation.
6. Why Some Plastics Follow a Different End-of-Life Pathway
Fragmentation changes the size of a plastic. Biodegradation changes the polymer itself.
Two Completely Different Processes
By now, we have seen that conventional plastics may gradually fragment into smaller and smaller particles through mechanical wear and environmental exposure.
Fragmentation is a physical process.
The polymer itself remains chemically unchanged.
Only the size of the particles decreases.
Biodegradation is fundamentally different.
Instead of simply breaking into smaller pieces, the polymer is progressively transformed by microorganisms into naturally occurring substances such as carbon dioxide, water, biomass and, in oxygen-free environments, methane.
This is a biological and chemical process, not simply a physical one.
Nature Has Been Recycling Carbon for Millions of Years
Long before plastics existed, microorganisms were already recycling organic matter.
Leaves.
Wood.
Roots.
Dead plants.
Animal remains.
These materials are continuously broken down by bacteria and fungi, allowing their carbon to return to natural biological cycles.
Scientists asked an important question:
Could certain polymers also be designed so microorganisms could eventually break them down after their useful life?
That question gave rise to the development of biodegradable polymers.
Designing a Different End-of-Life
Biodegradable polymers are not designed to disappear.
They are designed to perform their intended function first.
Only after that function has been completed, and under appropriate environmental conditions, can microorganisms begin the biodegradation process.
In other words, biodegradation is part of the material's design, not a manufacturing defect.
Just as durability is intentionally engineered into some polymers, biodegradation can also be intentionally engineered into others.
Two Different Pathways
Imagine two agricultural mulch films that perform the same function during the growing season.
One is designed for long-term persistence.
The other is designed with a biodegradable end-of-life.
Although both may look similar during use, their intended pathways after use are fundamentally different.
Figure 3. Although conventional plastics and certified biodegradable polymers may appear similar during use, they are engineered with fundamentally different intended end-of-life pathways. Conventional plastics generally fragment into progressively smaller particles, whereas certified biodegradable polymers are designed to be assimilated by microorganisms under defined environmental conditions.
Different environments may produce different biodegradation products.
Biodegradation Is Not Instantaneous
One of the most common misconceptions is that biodegradable plastics simply "disappear."
They do not.
Like leaves decomposing in a forest, biodegradation requires suitable environmental conditions.
Temperature.
Moisture.
Oxygen availability.
Microbial activity.
Time.
Without these conditions, biodegradation may occur much more slowly or may not proceed as intended.
This is why scientists evaluate biodegradable materials under clearly defined test conditions.
Science Before Claims
Not every plastic marketed as "green," "eco-friendly" or even "biodegradable" necessarily performs as claimed.
For this reason, internationally recognized testing methods and certification programs have been developed to verify biodegradation under specific conditions.
These standards allow scientists, regulators, manufacturers and users to evaluate materials using measurable, reproducible criteria rather than marketing claims.
Looking Ahead
Understanding biodegradation naturally leads to another question.
How do scientists verify that a material truly biodegrades as intended?
The answer lies in internationally recognized testing methods and certification standards.
That is the focus of the next chapter.
7. Understanding Certification Standards
Certification standards do not exist to create marketing claims. They exist to verify scientific claims.
Why Certification Matters
As biodegradable plastics began entering the marketplace, manufacturers, regulators and consumers faced an important challenge.
How could anyone distinguish between materials that truly biodegrade and those that simply claimed to?
Words such as green, eco-friendly, environmentally safe or even biodegradable have no scientific value on their own.
To evaluate materials objectively, internationally recognized testing methods and certification systems were developed.
Their purpose is simple:
Replace claims with measurable evidence.
What Is a Certification?
A certification is an independent verification that a material has successfully met a defined set of technical requirements.
Rather than relying on the manufacturer's own statements, accredited laboratories perform standardized tests under controlled conditions.
Only when all required criteria are met can a material receive certification.
This allows scientists, governments, manufacturers and consumers to evaluate products using common, reproducible methods.
Different Applications Require Different Standards
One of the most common misconceptions is that a single certification can answer every question about a material.
In reality, different standards were developed for different applications and different end-of-life environments.
Some standards evaluate industrial compostability.
Others evaluate biodegradable agricultural mulch films.
Others assess biodegradation in soil or marine environments.
Each standard answers a different scientific question.
A Certification Is Not a Universal Approval
Receiving one certification does not automatically demonstrate performance in every environment.
For example, a certification developed for industrial composting does not necessarily demonstrate biodegradation in agricultural soil.
Likewise, a soil biodegradation certification does not automatically demonstrate performance in a home compost system.
Every certification has a defined scope.
Understanding that scope is just as important as understanding the certification itself.
Standards vs. Certification
Although these terms are often used interchangeably, they are not the same.
A standard describes how a material should be tested.
A certification confirms that a material has successfully met the requirements defined by that standard.
In other words:
The standard defines the rules.
The certification confirms successful compliance with those rules.
Examples of International Standards
The field of biodegradable plastics includes several internationally recognized standards and certification programs.
Among the best known are:
EN 13432
ASTM D6400
EN 17033
ISO test methods used to evaluate biodegradation under specific conditions
TÜV Austria certification programs
Seedling®
OK compost
OK biodegradable SOIL
Each addresses specific questions about material performance and should always be interpreted within its intended scope.
The following sections explore these certifications in greater detail.
The Most Important Lesson
A certification does not answer every question about a material.
It answers one specific scientific question, under defined test conditions, using internationally accepted methods.
Understanding what a certification demonstrates is important.
Understanding what it does not demonstrate is equally important.
Looking Ahead
Now that we understand why certification systems exist, we can examine the major international standards used to evaluate biodegradable plastics and discover the specific questions each one was designed to answer.
8. Understanding Oxo-Degradable Plastics
Oxo-degradation accelerates fragmentation. It does not, by itself, demonstrate complete biodegradation.
Why the Term Creates Confusion
Oxo-degradable plastics are often presented as materials that break down more rapidly than conventional plastics.
At first glance, this may appear similar to biodegradation.
A product becomes brittle.
Cracks appear.
The material breaks into progressively smaller fragments.
Eventually, much of it may no longer be visible.
However, disappearance from sight is not the same as biological conversion.
To understand oxo-degradable plastics, we must return to the distinction introduced earlier:
Fragmentation changes particle size. Biodegradation changes the polymer itself.
What Is an Oxo-Degradable Plastic?
An oxo-degradable plastic is generally a conventional polymer—often polyethylene—containing additives designed to accelerate oxidation.
When the material is exposed to conditions such as heat, oxygen and ultraviolet radiation, oxidation weakens the polymer chains.
The plastic becomes more brittle and increasingly susceptible to fragmentation.
The process can be summarized as follows:
Conventional polymer
↓
Exposure to oxygen, heat and ultraviolet radiation
↓
Oxidation of the polymer
↓
Loss of strength and flexibility
↓
Fragmentation into smaller particles
The important question is what happens next.
Oxidation Is Not the Same as Biodegradation
Oxidation can reduce the molecular weight of a polymer and alter its physical properties.
It may make the material easier to fragment.
But oxidation alone does not demonstrate that microorganisms will completely assimilate the material.
A plastic may therefore break into pieces small enough to become difficult to see or recover while still remaining chemically identifiable as plastic.
This is why visual disappearance cannot be used as proof of complete biodegradation.
What Would Complete Biodegradation Require?
To demonstrate biodegradation, it is not sufficient to show that a product:
becomes brittle;
loses strength;
breaks apart;
disappears visually;
or produces particles below a certain size.
A scientifically demonstrated biodegradation pathway must evaluate what happens to the polymer carbon.
Under aerobic conditions, successful biodegradation ultimately involves conversion into substances such as:
carbon dioxide;
water;
microbial biomass;
and naturally occurring mineral residues.
The central question is therefore not:
Did the product break apart?
It is:
Was the polymer biologically converted?
Oxo-Degradable and Biodegradable Plastics Follow Different Design Principles
A certified biodegradable polymer is designed so that microorganisms can participate in the ultimate conversion of the material under defined conditions.
An oxo-degradable material generally begins with a persistent conventional polymer and uses additives to accelerate oxidative weakening and fragmentation.
These are fundamentally different approaches.
Oxo-Degradable Pathway
Conventional polymer > Oxidation > Embrittlement > Fragmentation > Smaller plastic particles
Certified Biodegradable Pathway
Biodegradable polymer > Environmental and microbial activity > Polymer-chain breakdown > Assimilation by microorganisms > Carbon dioxide + Water + Biomass*
*Under aerobic conditions.
The Problem With the Word “Degradable”
The word degradable is broad.
Almost every material degrades in some way when exposed to sufficient heat, light, abrasion, chemicals or time.
But degradation can refer to many different processes:
physical degradation;
mechanical degradation;
photodegradation;
oxidative degradation;
hydrolysis;
biodegradation.
These processes should not be treated as interchangeable.
A claim that a product is “degradable” does not tell us:
what mechanism is involved;
how completely the material changes;
how long the process takes;
which environmental conditions are required;
or whether persistent particles remain.
This is precisely why clear terminology and standardized testing are necessary.
What Certification Should Demonstrate
A meaningful biodegradation claim should be supported by standards that evaluate more than visible fragmentation.
Depending on the intended environment, certification may assess:
conversion of the material’s carbon;
the percentage of biodegradation achieved;
the time required;
disintegration;
ecotoxicity;
heavy-metal limits;
effects on plant growth;
and the environmental conditions under which the claim applies.
An oxo-degradable claim should therefore never be assumed equivalent to a certified compostability or soil-biodegradation claim unless the material independently satisfies the applicable requirements.
Why This Distinction Matters in Agriculture
Agricultural plastics are exposed to demanding conditions:
ultraviolet radiation;
heat;
wind;
soil abrasion;
machinery;
repeated tension;
installation and removal.
A material designed to oxidize and fragment may become increasingly difficult to recover as it loses strength.
In an agricultural environment, smaller fragments can mix with the soil and become difficult to distinguish from organic matter or mineral particles.
The intended end-of-life pathway therefore matters as much as the product’s performance during use.
The appropriate question is not simply:
Will this film break down?
It is:
What will the material become after it breaks down?
What an Oxo-Degradable Claim Demonstrates—and What It Does Not
It may demonstrate:
accelerated oxidation;
loss of mechanical strength;
embrittlement;
faster fragmentation under certain conditions.
It does not automatically demonstrate:
complete biodegradation;
microbial assimilation;
conversion into carbon dioxide, water and biomass;
absence of persistent microplastics;
suitability for composting;
suitability for biodegradation in soil;
compliance with a recognized biodegradation standard.
The Most Important Lesson
Oxo-degradable plastics illustrate why the words degradation, fragmentation and biodegradation must be used carefully.
A material can degrade physically without biodegrading completely.
It can become invisible without ceasing to be plastic.
It can fragment rapidly while its polymer carbon remains in the environment.
The scientific question must therefore extend beyond appearance:
What happens to the polymer itself?
Looking Ahead
Oxo-degradable plastics demonstrate how easily environmental claims can be misunderstood when terminology is imprecise.
The next chapter examines another source of confusion: chemical additives and substances such as PFAS.
Unlike biodegradability, which concerns the fate of the polymer, this question concerns something different:
What chemicals may be present in or added to a material—and what risks do they create?
9. Understanding PFAS
PFAS and biodegradability are two different scientific questions. One concerns the chemicals that may be used during manufacturing. The other concerns what happens to a material after its useful life.
Why Discuss PFAS in a Guide About Plastics?
As concerns about plastic pollution have grown, discussions increasingly include another family of substances: PFAS (Per- and Polyfluoroalkyl Substances).
Although PFAS and plastics are often mentioned together, they should not be confused.
PFAS are not plastics.
They are a large family of fluorinated chemicals used in many industrial applications because of their exceptional chemical stability.
How Have PFAS Been Used in the Plastics Industry?
Historically, certain PFAS-based additives have been used as Polymer Processing Aids (PPAs) during the extrusion of some polymers, particularly polyolefins such as polyethylene.
Their purpose is to improve the manufacturing process—not the function of the finished product.
By reducing friction between molten plastic and the metal surfaces of the extrusion equipment, they help minimize a surface defect known as melt fracture, producing smoother films with improved surface finish and print quality.
In recent years, however, the plastics industry has been actively moving toward fluorine-free processing technologies as alternatives become available.
Why Are PFAS a Concern?
PFAS are often referred to as "forever chemicals" because many members of this chemical family are extremely resistant to degradation.
Their exceptional stability allows them to persist in the environment for very long periods of time.
Some PFAS have also been shown to accumulate in water, wildlife and the human body, raising concerns about their long-term environmental and health impacts.
This persistence is the primary reason PFAS have become the focus of increasing scientific research and regulatory attention around the world.
A Different Type of Persistence
Although polyethylene and PFAS may both persist for long periods, they are fundamentally different materials.
Polyethylene is a polymer designed primarily to provide durability during use.
PFAS are fluorinated chemicals valued for their exceptional chemical stability.
Both may be persistent, but they are persistent for different scientific reasons and serve completely different functions.
Biodegradable Polymers and PFAS
Most biodegradable polymer systems do not require fluorinated Polymer Processing Aids during extrusion.
More importantly, biodegradability and PFAS are independent characteristics.
A material should therefore be evaluated separately for:
its polymer chemistry;
its intended end-of-life pathway;
and the presence or absence of substances such as PFAS.
Each question requires its own scientific evidence.
The Key Takeaway
PFAS concern how some materials have historically been manufactured.
Biodegradability concerns what happens to a material after it has completed its intended function.
These are different scientific questions and should never be confused.
Understanding this distinction allows materials to be evaluated objectively, based on evidence rather than association.
Looking Ahead
We have now explored the fundamental concepts needed to understand modern plastics:
what plastics are;
how they are classified;
how microplastics are formed;
why some polymers are designed to biodegrade;
how certification standards verify scientific claims;
and why PFAS represent a separate environmental consideration.
The following chapter brings these concepts together and examines how they can be applied when selecting the most appropriate material for a specific application.
10. Conclusion
Throughout this guide, one principle has remained constant:
No single characteristic is sufficient to evaluate a plastic material.
Plastics are a diverse family of engineered materials developed to meet a wide range of performance requirements. A meaningful assessment therefore requires considering several independent properties, including:
the chemical composition of the polymer;
whether it is bio-based or fossil-based;
its intended application;
its expected service life;
its end-of-life pathway;
the presence or absence of substances of concern, such as PFAS;
and, when applicable, compliance with recognized certification standards.
Each of these characteristics answers a different scientific question.
Understanding the distinction between these questions is essential for informed discussions about plastics and for selecting the most appropriate material for a given application.
A Final Thought
One misunderstanding has become increasingly common: assuming that a material is environmentally preferable simply because it is bio-based.
The origin of the carbon does not determine the environmental behavior of a material.
A bio-based plastic particle found in the environment—or in the human body—is no more desirable than a fossil-based plastic particle simply because its carbon originated from plants.
Likewise, a biodegradable material may be partly derived from fossil resources while still being specifically designed to be assimilated by microorganisms at the end of its useful life.
This illustrates one of the central messages of this guide:
The origin of the carbon and the end-of-life behavior are independent material properties.
Both must be considered when evaluating environmental performance.
Scientific decisions should therefore be based on measurable evidence rather than on a single characteristic or a simplified label.
No material is inherently "good" or "bad." The most appropriate material is the one whose properties—including its intended function, service life and end-of-life pathway—are best matched to its application.
11. Glossary
Bio-based
A material derived wholly or partly from renewable biological resources such as plants, agricultural residues or other forms of biomass. Bio-based content does not, by itself, indicate whether a material is biodegradable.
Biodegradation
The process by which microorganisms convert a material into naturally occurring substances such as carbon dioxide, water, biomass and, under specific conditions, methane.
Biodegradable Plastic
A plastic specifically designed to undergo biodegradation under defined environmental conditions and within the limits established by the applicable standard.
Biodegradable Polymer
A polymer capable of being assimilated by microorganisms under defined environmental conditions.
Bioplastic
A general term describing plastics that are bio-based, biodegradable, or both. The term does not refer to a single family of materials.
Certification
Independent verification that a material or product complies with the requirements of a recognized standard.
Compostable Plastic
A biodegradable plastic that meets the requirements of a recognized compostability standard under specified composting conditions.
Conventional Plastic
A plastic generally produced from fossil-based resources and designed primarily for durability during use.
End-of-Life
The stage reached after a product has fulfilled its intended function, including reuse, recycling, composting, biodegradation or disposal.
Fragmentation
The physical breakdown of a material into progressively smaller pieces. Fragmentation reduces particle size but does not necessarily demonstrate biodegradation.
Life Cycle
The sequence of stages a material undergoes, from raw material production through manufacturing, use and end-of-life.
Microplastic
A plastic particle measuring less than 5 mm in its largest dimension. The term describes particle size only and does not indicate the origin, chemistry or persistence of the material.
Nanoplastic
A plastic particle in the nanometre size range. Scientific definitions continue to evolve.
Oxo-degradable Plastic
A conventional plastic containing additives intended to promote oxidation and fragmentation. Oxidation and fragmentation do not, by themselves, demonstrate biodegradation.
PBAT (Polybutylene Adipate Terephthalate)
A biodegradable polymer commonly used to provide flexibility and toughness in biodegradable plastic formulations.
PE (Polyethylene)
The world's most widely used plastic. Polyethylene is used in packaging, agricultural films, pipes, containers and many other applications. Conventional polyethylene is not biodegradable.
PET (Polyethylene Terephthalate)
A durable polymer commonly used for beverage bottles, food packaging and synthetic fibres.
PHA (Polyhydroxyalkanoates)
A family of biodegradable polymers naturally produced by microorganisms from renewable feedstocks.
PLA (Polylactic Acid)
A polymer produced from renewable resources such as fermented plant sugars. Depending on the product design and certification, PLA may be intended for composting under defined conditions.
Polymer
A large molecule composed of repeating structural units (monomers). Polymers are the fundamental building blocks of plastics.
Polymer Processing Aid (PPA)
An additive used during manufacturing to improve polymer extrusion and processing efficiency. Historically, some PPAs were fluorinated; today, fluorine-free alternatives are increasingly available.
PP (Polypropylene)
A durable polymer widely used in packaging, automotive components, textiles and consumer products.
Persistence
The ability of a material or substance to remain in the environment over time without being completely degraded or transformed.
PFAS (Per- and Polyfluoroalkyl Substances)
A large family of fluorinated chemicals used in many industrial applications because of their exceptional chemical stability. PFAS are a separate scientific consideration from biodegradability.
Plastic
A broad family of polymeric materials engineered to provide specific combinations of mechanical, thermal and chemical properties for a wide variety of applications.
Plastic Particle
Any discrete fragment or piece of plastic, regardless of its size, origin or chemical composition.
PVC (Polyvinyl Chloride)
A durable polymer widely used in pipes, flooring, window frames, medical devices and electrical insulation.
PS (Polystyrene)
A polymer commonly used in packaging, insulation, disposable products and consumer goods.
Renewable Carbon
Carbon originating from contemporary biological sources rather than fossil resources.
Service Life
The period during which a material is designed to perform its intended function before reaching its end-of-life.
Standard
A published technical document that defines test methods, performance requirements or evaluation criteria for materials or products.
References
Standards and Certification
ASTM International. (Current edition). ASTM D6400 – Standard Specification for Labeling of Plastics Designed to be Aerobically Composted in Municipal or Industrial Facilities.
ASTM International. ASTM D6866 – Determining the Biobased Content of Solid, Liquid and Gaseous Samples Using Radiocarbon Analysis.
ASTM International. ASTM D5988 – Standard Test Method for Determining Aerobic Biodegradation of Plastic Materials in Soil.
European Committee for Standardization (CEN). EN 13432 – Requirements for Packaging Recoverable through Composting and Biodegradation.
European Committee for Standardization (CEN). EN 17033 – Biodegradable Mulch Films for Use in Agriculture and Horticulture.
ISO 17556. Determination of the Ultimate Aerobic Biodegradability of Plastic Materials in Soil.
ISO 14855. Determination of the Ultimate Aerobic Biodegradability of Plastic Materials under Controlled Composting Conditions.
Plastics and Polymer Science
Andrady, A. L. (Ed.). Plastics and Environmental Sustainability.
Brydson, J. A. Plastics Materials.
Gedde, U. Polymer Physics.
Odian, G. Principles of Polymerization.
Bioplastics
European Bioplastics. Bioplastics Market Data.
European Bioplastics. Frequently Asked Questions.
BASF. Technical literature on biodegradable polymers.
NatureWorks LLC. Technical literature on PLA.
Microplastics
GESAMP. Sources, Fate and Effects of Microplastics in the Marine Environment.
UNEP. From Pollution to Solution: A Global Assessment of Marine Litter and Plastic Pollution.
WHO. Microplastics in Drinking Water.
PFAS
OECD. Toward a New Comprehensive Global Database of PFAS.
U.S. Environmental Protection Agency (EPA). PFAS Technical Resources.
European Chemicals Agency (ECHA). PFAS Information Portal.
Composting and Biodegradation
TÜV AUSTRIA. Certification Program Documentation.
DIN CERTCO. Certification Programs.
European Commission. Reports on biodegradable plastics.
Agriculture
FAO. Publications on agricultural plastics.
FAO. Assessment of Agricultural Plastics and Their Sustainability.
Government and Public Institutions
Environment and Climate Change Canada.
U.S. EPA.
European Commission.
OECD.
Suggested Reading and Further Reading
If readers wish to explore these topics further, the publications and standards referenced above provide comprehensive scientific and technical information on plastics, bioplastics, biodegradation, compostability, certification and environmental assessment.
Continue Exploring
Now that you've explored the fundamentals of plastics, bioplastics, microplastics and end-of-life pathways, continue with the three practical pillars of our educational series.
💰 Labor & Economics
The Real Cost of Plastic Mulch Removal
Discover the hidden costs of plastic mulch after harvest, including labor, transportation and disposal.
▶ Explore Labor & Economics
🌱 Soil & Microplastics
What Actually Remains in the Soil After Plastic Mulch
Learn how conventional plastic fragments over time and why understanding end-of-life pathways matters.
▶ Explore Soil & Microplastics
🚜 Field Experience
Compostable Mulch Performing in Real Farm Conditions
See how compostable mulch performs under commercial growing conditions throughout the season.