Eight must-know notions about plastics

There’s no denying the fact that plastics have become an integral part of our modern lives. In 2021, global plastics production was estimated at 390.7 million metric tons. Considering their environmental and health impact, it is important to understand fundamental notions about plastics - in order to find alternatives to part ways with them.

This article presents eight must-know notions about plastics. Whether you are curious about the different types of plastics, their manufacturing processes, or the alarming issue of plastic pollution, this article aims to provide a straightforward overview of these crucial aspects.

1. The nature and varieties of plastic

Plastics are synthetic or semi-synthetic materials made from polymers — long chains of molecules. They come in many different forms and types, including thermoplastics like polyethylene and PVC, thermosetting polymers like vulcanized rubber, and elastomers.

Thermoplastics

Thermoplastics are polymers that can be melted and re-molded multiple times without undergoing significant degradation. This characteristic is due to the linear or branched molecular structure, which allows the polymer chains to slide past each other when heated. When cooled, thermoplastics solidify and retain their new shape. Some common examples of thermoplastics include polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC), and polystyrene (PS). Thermoplastics find widespread use in various industries, such as packaging, automotive, construction, and consumer goods.

Thermosetting polymers

Thermosetting polymers, or "thermosets," are crosslinked polymers that undergo a chemical reaction during curing, forming a rigid and infusible network structure. Once cured, thermosets cannot be melted or reshaped through heat alone. The crosslinks provide enhanced stability, strength, and resistance to heat, chemicals, and electricity. Thermosetting polymers are commonly used in applications that require durability, such as in electrical insulation, composites, adhesives, and automotive parts.

Thermosetting vs Thermoplastic: the basic difference between them is that thermoplastics can be melted back again into the liquid state while the thermosets cannot(Source)

💡Download our plastic glossary to learn about different types of plastics

2. Plastic manufacturing process

The process of making plastics, known as polymerization, involves combining smaller molecules, or monomers, into long chains or polymers.

Monomers and polymers

The different ways of doing this include addition polymerization and condensation polymerization.

Addition polymerization

In this technique, monomers are chemically joined together to form a polymer chain, with no byproducts produced. The reaction occurs through the repeated addition of monomers initiated by heat, light, or chemical initiators.

Addition polymerization is commonly used for plastics such as polyethylene (PE) often used in packaging or pipes, polypropylene (PP) often used in textile or food containers, and polystyrene (PS) often used in food service products.

Condensation polymerization

This technique involves the reaction between two different monomers, with the elimination of a small molecule like water or alcohol as a byproduct. The monomers react through their functional groups, forming covalent bonds and producing a polymer chain.

Examples of plastics produced through condensation polymerization include polyesters like PET (polyethylene terephthalate) (often used for plastic packaging) and polyamides like nylon.

Addition polymer VS Condensation polymer (Source)

3. Recyclability

The recyclability of plastic is a topic that generates a lot of attention. First, not all plastics are recyclable - for example, plastic bags or straws are typically not easy to recycle. Plastic coffee cups can be recycled, if there is a certain machine.

““Recycling” is determined by two really important things: the market and city government. If there’s a demand in the market, then recyclers and companies will pay for your post-consumer recyclables.”

• National Geographic

The number inside the recycling symbol on a plastic item indicates the type of plastic it is, and this can influence whether or not it can be recycled.

Plastics are classified into different resin codes, indicated by the numbers inside the chasing arrows symbol (♻️). While some resin codes, such as #1 (PET) and #2 (HDPE), are widely accepted for recycling, others, like #3 (PVC) and #6 (PS), face more limited recycling options due to their composition or lack of market demand for recycled materials. It is essential to check local recycling guidelines to determine which types of plastics are accepted in specific recycling programs.

4. Environmental impact of plastics

Plastics can have a significant impact on the environment. One of the concerning aspects is their long decomposition time, which can span hundreds of years. This means that plastic waste persists in landfills, oceans, and natural habitats for extended periods, contributing to environmental pollution.

According to the Center for Biological Diversity, plastic wastes make up about 40 percent of the world's ocean surfaces. The accumulation of plastic waste in ecosystems poses a serious threat to wildlife, as animals can mistake plastic for food or become entangled in it, leading to injury, suffocation, or even death.

Furthermore, the production and disposal of plastics contribute to global greenhouse gas emissions. Plastics are primarily derived from fossil fuels, and their manufacturing processes release carbon dioxide and other greenhouse gases into the atmosphere. Additionally, the incineration of plastic waste can release harmful pollutants and exacerbate air pollution. Plastic waste that ends up in landfills can also generate methane, a potent greenhouse gas.

5. Microplastics

When plastics break down, they can form tiny particles known as microplastics. These microplastics have become a growing concern due to their pervasiveness in the environment and their potential to cause harm to animals and humans.

Microplastics can enter ecosystems through various sources, including the breakdown of larger plastic items, the shedding of microfibers from textiles, and the fragmentation of plastic waste. Hence, microplastics can accumulate in soil, rivers, lakes, oceans, and even in the air we breathe. Once in the environment, they can be ingested by marine life, birds, and other animals, potentially causing physical harm, disrupting their digestive systems, and affecting their overall health.

Moreover, microplastics have been found in various food sources, including seafood, salt, and even tap water, raising concerns about their potential impact on human health.

While the full extent of the effects of microplastics on ecosystems and human well-being is still being studied, there is a growing consensus that minimizing the release of plastic waste and finding effective solutions for their removal from the environment are essential steps toward mitigating the risks associated with microplastics.

6. Bioplastics

Some plastics are made from renewable biomass sources, such as vegetable fats and oils or corn starch, leading to the emergence of a category known as bioplastics. Bioplastics offer a potential alternative to traditional plastics derived from fossil fuels. While it's important to note that not all bioplastics are inherently environmentally friendly, they are generally considered more sustainable than their conventional counterparts.

Certain types of bioplastics are designed to be biodegradable or compostable under specific conditions.

• Biodegradable bioplastics break down naturally through biological processes, reducing their long-term environmental impact
• Compostable bioplastics can be converted into nutrient-rich compost through industrial composting facilities, facilitating the transition to a circular economy.

💡 Download our plastic glossary to learn more about bioplastics

7. Health impact of plastics

Some plastics contain chemicals, such as phthalates or bisphenol A (BPA), which have raised concerns regarding potential health risks. These chemicals are known as plasticizers and are used to enhance the flexibility, durability, and transparency of plastics. However, there are worries that these chemicals can leach out of plastics and migrate into food or drinks, particularly when exposed to heat.

Research suggests that exposure to phthalates and BPA may be associated with adverse health effects. Phthalates, for example, have been linked to hormonal disruptions, reproductive system abnormalities, and potential developmental and reproductive issues in animal studies. On the other hand, BPA has been identified as an endocrine disruptor and associated with various health concerns, including hormonal imbalances, obesity, and potential developmental and reproductive effects.

8. Single-use plastics

Single-use plastics are designed for one-time use before being discarded or recycled. Common examples include plastic bags, straws, coffee stirrers, soda and water bottles, and various forms of food packaging. Unfortunately, their convenience and widespread use have contributed to a significant accumulation of plastic waste.

The disposable nature of these items means that they are often used for only a short period but persist in the environment for hundreds of years. Single-use plastics have become a major source of plastic pollution, with significant impacts on ecosystems, wildlife, and human health. In 2021, the world generated 139 million metric tons of single-use plastic waste. The improper disposal of these items, such as littering or inadequate waste management, further exacerbates the problem, as they can end up in rivers, oceans, and natural habitats.

💡 Check out the top 100 suppliers who will change the future of the single-use plastic industry.

Final thoughts

There are numerous strategies in place to reduce the environmental impact of plastics.

To combat plastic waste, many jurisdictions worldwide are implementing regulations and policies. These include bans or restrictions on certain types of single-use plastics, such as plastic bags, straws, and foam packaging.

Furthermore, Extended Producer Responsibility (EPR) programs are being implemented in various regions. In Europe, the European Union’s EPR is compulsory for waste from electric and electronic equipment, batteries and accumulators, and end-of-life vehicles. Similarly, there are EPR programs in place in the United States and Canada, covering packaging, batteries, and electronics.

These programs hold manufacturers accountable for the entire lifecycle of their plastic products, encouraging them to design for recyclability and invest in recycling infrastructure.

Another effective approach is to embrace alternative materials, which are more environmentally friendly or can be recycled or reused.

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Sources

Extended Producer Responsibility - OECD. (n.d.). https://www.oecd.org/environment/extended-producer-responsibility.html

Howes, L. (2019). EU adopts plastics ban. Chemical & Engineering News. https://cen.acs.org/policy/legislation-/EU-adopts-plastics-ban/97/i21

Ocean Plastics Pollution. (n.d.). https://www.biologicaldiversity.org/campaigns/ocean_plastics/

Parker, L. (2021, May 3). Microplastics found in 90 percent of table salt. Environment. https://www.nationalgeographic.com/environment/article/microplastics-found-90-percent-table-salt-sea-salt

Statista. (2023, June 12). Global plastic production 1950-2021. https://www.statista.com/statistics/282732/global-production-of-plastics-since-1950/

Ventosa, I. P., & Ventosa, I. P. (2022). The Concept of Generalised Extended Producer Responsibility (GEPR) | EcoMENA. EcoMENA. https://www.ecomena.org/generalised-extended-producer-responsibility/

Wang, Y., & Qian, H. (2021). Phthalates and Their Impacts on Human Health. Healthcare, 9(5), 603. https://doi.org/10.3390/healthcare9050603

Whiteman, H. (2023, February 6). The world is creating more single-use plastic waste than ever, report finds. CNN. https://edition.cnn.com/2023/02/05/energy/single-use-plastics-volume-grows-climate-intl-hnk/index.html