The Great Plastic Remake - Introduction to plastics
This is post 1 of our series of 3 posts supporting outreach activities to understand the role of bioplastics and molecular biosciences in addressing plastic waste. On this post we talk about conventional plastics and explore their popularity.
The 45th FEBS Congress has a Special Session organized by the FEBS Science and Society Committee on plastic pollution and potential plastic substitutions. To accompany this session, FEBS Open Bio published a series of articles on bioplastics in their April 2021 issue.
We have also published a series of three Outreach Room posts for Constituent Societies that want to engage the public on this topic. The posts provide an overview on plastics (post 1 - this one), the problems of plastic waste (post 2), and bioplastics (post 3). The posts also include activities to develop with different groups, and links to additional information resources.
Key points to consider
Below are a set of key messages to explore in an outreach activity:
- Plastics are durable, versatile and cheap, which makes them useful and popular.
- Their durability and popularity, as well as the way plastic is used and disposed of (e.g., single use plastics, low rates of recycling, mismanaged waste processing), create a huge amount of plastic waste.
- Plastic waste accumulates in the environment and has an impact on the biosphere. This impact ranges from marine organisms consuming fragments of plastic present in the water to CO2 released into the atmosphere during the making and disposing of plastic.
- Dealing with plastic waste is a complex problem that needs stakeholders to collaborate to find solutions, or at least be aware of each other’s work. Stakeholders include consumers, industry, governments, civil organisations, and researchers.
- Solutions need to be implemented at all stages of the plastic lifecycle (production, usage, collection, waste management, circular economy, stop leaking into the sea).
- Recycling of plastic is complex but can be improved. Part of the solution resides in revalorising plastic (i.e., it should not be considered valueless waste).
- Bioplastics can improve the sustainability of plastic, but they are not a complete fix, and as such need to be considered within the broader set of solutions.
What are plastics?
Plastics are a group of materials used to make a huge variety of products, from packaging and building materials to parts in cars, toys, and electronics. The raw materials used in plastic are obtained from crude oil, coal and natural gas. Novel sources such as cellulose, bioethanol and compounds produced by bacteria are also used nowadays.
Plastic materials are composed of polymers, which are macromolecules made up of long chains of smaller units called monomers. The monomers in plastic materials are molecules of compounds such as ethylene, propylene, styrene, phenol, or vinyl chloride, among many others. Monomers bond to form chains by polymerisation or by polycondensation. These chains can be linear or branched and can contain one or more types of monomers.
The chemical nature of the individual monomers determines the properties, structure, and size of the polymer. Additional chemical modifications can be carried out, or substances added (e.g., plasticisers, stabilisers, pigments, etc.) to obtain the desired properties for the final plastic material, such as its rigidity, strength, and resistance to heat, moisture, impact, and corrosion.
Plastic has many names. Consumers will be familiar with terms such as polyester, nylon, vinyl, Styrofoam, Plexiglass and Teflon, which mix product and brand names. They might also be aware of the ASTM International Resin Identification Coding System. This is the code moulded onto some products that identifies which plastic material it is made from, to help with recycling purposes. The code system is as follows:
- Code 1: Polyethylene Terephthalate (PET) (beverage bottles, cups, other packaging, etc.)
- Code 2: High-Density Polyethylene (HDPE) (bottles, cups, milk jugs, etc.)
- Code 3: Polyvinyl Chloride (PVC) (pipes, siding, flooring, etc.)
- Code 4: Low-Density Polyethylene (LDPE) (plastic bags, six-pack rings, tubing, etc.)
- Code 5: Polypropylene (PP) (auto parts, industrial fibres, food containers, etc.)
- Code 6: Polystyrene or Styrofoam (PS) (plastic utensils, Styrofoam, cafeteria trays, etc.)
- Code 7: Miscellaneous plastics (other plastics, such as acrylic, nylon, polycarbonate and polylactic acid).
Miscellaneous plastics includes some of the newer materials, such as biodegradable plastics, which will be explored further in this post.
Why is plastic so popular?
Plastic is durable, versatile, light, and often cheap. It can be moulded into a wide variety of shapes and by using different plastic materials we can obtain final products with a range of useful properties.
Many household items and consumer products, such as electronics and clothing, are made from plastic materials, usually from polyethylene, polypropylene, or polystyrene. Plastics are also used in construction and in agriculture, as well as in industry, where novel engineering plastics are increasingly replacing metals in industrial applications from car parts to machine components.
Plastic materials are particularly important in healthcare and scientific research, where they help to avoid contamination and enable many procedures and experiments to be carried out safely and effectively.
While plastic products are undeniably useful, the increasing amount of plastic produced and the growing trend to use plastics in disposable items, has led to a huge problem with plastic waste.
On the second post of these series we explore the problems caused by plastic waste, as well as touch on issues around the production of greenhouse gases and pollution.
Use these suggested activities as inspiration to develop an outreach session to engage the public with some of the issues described above:
- Plastics Challenge (downloadable resources from Practical Action, a development organisation).
- Which Plastic is Which Shrinking Cup Experiment (from Left Brain Craft Brain).
- Olly’s Cool Box Of Plastics (from PlasticsEurope, the Association of Plastic Manufacturers).
- Use Lego pieces to explain monomers and polymers in plastic materials, as well as additives.
- Give children information on recycling and on the Resin Identification Code System, and then send them to the supermarket to identify and document different types of plastic, or bring different plastic products from home.
- Get children to collect different types of plastics and create art pieces (e.g., sculptures), machines, or landscapes.
These websites provide additional sources of information:
- Royal Society of Chemistry (search their website for education resources about plastics).
- American Chemical Society (search their website for education resources about plastics).
- PlasticsEurope (a useful resource to learn about types of plastics and their uses, from the Association of Plastic Manufacturers).