As new research emerges, the alarming presence of tiny plastic particles, called microplastics, has become a hot topic among consumers alike. What they are, how they affect us, where they come from, and where they are found are all questions we need answers to. This new wave of information has caused rising health and environmental concerns with plastic use, and consumers are frantically seeking plastic-free alternative materials.
In this blog series, Rheom Material’s Materials R&D Engineer, Bobby Haney, Ph.D. completes a deep dive into the world of microplastics research. Answering the most asked questions, addressing consumer concerns, and exploring alternative materials. In part one of this three-part blog series, we answer the question: What are microplastics, and where do they come from?
What Are Microplastics? Definition, Size, and Key Traits
While various definitions exist, microplastics are generally defined as small, often microscopic, particles made of synthetic polymers and are resistant to biodegradation. More specifically, the U.S. Environmental Protection Agency (EPA) defines them as plastic particles in a size range from 1nm to 5mm. Microplastics are classified by their microscopic size, permitting easy ingestion, their ability to persist in environments for multiple years, their progressive fragmentation into smaller pieces to a nano-scale, and being almost impossible to remove from the environment after exposure.
Primary vs. Secondary Microplastics: What's the Difference?
There are two classes of microplastics defined by their origin: primary microplastics and secondary microplastics. Primary microplastics originate from plastics intentionally designed to be small in size, for example, glitter and microbead exfoliants. However, secondary microplastics derive from larger plastic items and unexpectedly break off, for example, from plastic water bottles or children’s toys.
Accurate classification of plastics is essential to halt the production of intentionally produced microplastics and to prevent their release into the environment. For instance, the production of microbead exfoliants used in cosmetics falls under the category of primary microplastics, as they are intentionally produced to be microscopic in size. As a result, government responses included bans on certain microplastic-containing products, particularly microbeads in cosmetics. In this instance, the correct classification of microbeads as primary microplastics led to prompt action that safeguarded human health and the environment. However, the classification of certain prevalent plastics, such as tires and synthetic fibers, remains undecided. This highlights the need for more research and better classification methods to further improve microplastic mitigation efforts.
Common Sources of Microplastics in Daily Life
From home décor to food containers, microplastics can originate from any plastic material. The European Chemicals Agency (ECHA) has identified a variety of polymers as microplastic producers: polypropylene (PP), polyurethane (PU), polyvinyl (PVC), polyethylene), polyamide (PA), polystyrene (PS), polyester(PES), and polyacrylamide(PAM). These materials are commonly used in plastic food packaging, bottles, bags (PP and PE), footwear foams, insulation foams (PU), water pipes, construction materials (PVC), nylon (PA), tires, synthetic fabrics (PES), Styrofoam (PS), and as an additive in toiletries (PAM).
How Microplastics Are Formed: Everyday Examples
Plastic is ubiquitous, and unfortunately, so are microplastics. These tiny particles can originate from various sources, including the everyday wear and tear of plastic items, degradation from environmental exposure, or mechanical abrasion during use. As plastics come into contact with other surfaces, small fragments break off, contributing to the proliferation of microplastics in the surrounding area.
Before being thrown away, the rate at which these materials produce microplastics varies based on their chemical structure, production method, and the final product's intended use, with the final use being the most influential factor. The extent of usage and the level of abrasion experienced during use significantly impact the rate of microplastic production. For instance, in a home, a plastic picture frame hung up on display will generate microplastics at a slower rate than a plastic cutting board that endures the sharp edge of a knife on a daily basis.
Brushing your hair with a plastic hairbrush, walking in tennis shoes on pavement, accidentally dropping your phone with a plastic phone case, and carrying and moving heavy groceries with a plastic bag, are just some of the everyday activities that can lead to the release of microplastics at various rates. It is also well known that two of the most common origins of microplastics are from washing synthetic textiles and the friction of car tires on the road. One study found that washing a 5kg standard load of polyester clothing, a textile that accounts for “52% of the global fiber market,” produced over six million microplastic fibers depending on the detergent.
While plastic is everywhere, by identifying the major producers of microplastics in your life and swapping them for plastic-free materials, you can reduce your exposure.
Reducing Microplastics: What You Can Do & What’s Coming Next
At Rheom Materials, we recognize consumers’ concerns and are engineering solutions to plastic by creating next-gen, biobased materials designed to reduce microplastics and biodegrade at their end of life.
Tune in to our next blog post, “Microplastics: From Ocean Depths to Human Bodies” to find out more about the potential consequences of microplastics in our bodies and the environment.
