Plastic has been undoubtedly one of the most important aspects of our lives. Used in packaging across a wide range of industries, in the manufacture of our clothing, electronics, as well as our products, the significance of plastic cannot simply be overlooked.
Over the several last decades, we have also been made aware of the dangers of plastics to our planet and our health as rampant waste and overconsumption ensues.
Let’s now dive deeper into the world of plastics. Specifically, the seven different types of plastic we encounter almost every day, in terms of their properties, common uses, and dangers (beware!).
Type 1: Polyethylene Terephthalate (PET or PETE)
PET is a highly flexible, colorless, and semi-crystalline resin in its natural state, and it can be semi-rigid to rigid depending on the way it is processed.
Overall, it is strong and lightweight (making it easy to transport) and has advantages such as being able to keep carbon dioxide in carbonated drinks from escaping. As it does not shatter, it is also a good replacement for glass. PET also has excellent electrical insulating properties and, most importantly, it is 100% recyclable – it is the most recycled plastic worldwide!
- Plastic bottles to hold drinking water and carbonated beverages
- Food packaging
- Rigid cosmetic jars
- Microwaveable containers
- In the textile industry as polyester fabrics
Over the last decade, several studies have shown that antimony (Sb), a cumulative toxic element in the environment with unknown biological functions, is able to migrate from the PET plastic bottles inside drinking water.
Through a study investigating PET safety in regards to the release of Sb in Mexican water PET bottles, Chapa-Martínez et al. (2016) found that antimony indeed leached from the PET bottles into the water.
Moreover, the release of Sb from PET significantly increased with the storage temperature (75 °C), indicating that temperature plays a part in determining the leaching of Sb into drinking water.
Essentially, this means that you could be drinking antimony from bottled water from a plastic bottle that has been exposed to higher temperatures for several days – and this may have long-term implications on your health!
Type 2: High-Density Polyethylene (HDPE)
Polyethylene itself is a lightweight, durable thermoplastic with different crystalline structures.
High-density polyethylene, or HDPE, is manufactured at low temperatures and pressures and is derived from either modifying natural gas (i.e., methane, ethane, or propane mix), or the catalytic cracking of crude oil into gasoline.
HDPE has very good resistance to alcohols, dilute acids and alkalis but has poor resistance to hydrocarbons. It also has good electrical insulating properties and it is a low-cost polymer. Most importantly, it is recyclable!
- Packaging applications, such as crates, trays, milk bottles, industrial bulk containers, laundry/shampoo containers, etc.
- Garbage containers, ice boxes, toys, housewares, etc.
- Fibres and textiles, such as ropes, fishing nets, agricultural nets
- Pipes and fittings, such as cable protecting, steel pipe coating, wiring and cables
Despite its durability, HDPE is susceptible to stress cracking, and it also has poor UV and low heat resistance.
Environmental stress cracking is a leading cause of embrittlement in plastics as polymers are affected by elements such as water, vapours or organic liquids.
Also, it most definitely does not biodegrade.
Type 3: Polyvinyl Chloride (PVC)
Polyvinyl chloride, or PVC, is an economical and versatile thermoplastic polymer. It is a lightweight, white-coloured, brittle, solid material that comes at a low cost and easy processability.
PVC is resistant to all inorganic materials and is resistant to weathering, chemical rotting, corrosion, shock and abrasion, and so it can be stored for a long period of time.
In terms of electrical properties, PVC is also a good insulation material. It is resistant to all inorganic chemicals, and it has good resistance against diluted acids.
Whether PVC is recyclable will have to depend on your local recycler and whether they accept PVCs.
Widely used in the construction industry to produce door and window profiles, drinking and wastewater pipes, wire and cable insulation, medical devices, etc.
PVC has been dubbed by some medical researchers and environmentalists as the “poison plastic” as it can contain as much as 57% of chlorine and carbon.
With its high chlorine content, PVC can create toxic pollution in the form of dioxins, and individuals may be exposed to phthalates as well, which may have serious health consequences.
Proper disposal of PVC will ensure that PVC is handled correctly at the end of its lifetime. However, according to EcoWatch, it becomes problematic when it ends up in landfills instead of recycling facilities, where PVC will leak harmful chemicals when burned or buried, contaminating the environment.
Type 4: Low-Density Polyethylene (LDPE)
Low-density polyethylene, or LDPE, is a semi-rigid and translucent polymer.
It has good resistance to alcohols, dilute alkalis and acids, and it is a low-cost polymer with excellent electrical insulating properties.
- Used to make thin, flexible products such as plastic bags for dry-cleaning, bread, fresh produce and garbage.
- Shrink-wrap, stretch film
- Coatings on paper milk cartons and disposable beverage cups
- Pharmaceutical bottles, thin bottle caps
- Water pipes and hoses
Similar to HDPE, LDPE is also susceptible to stress cracking, and it has low strength and maximum service temperature. This reduces its range of applications that require extreme temperatures.
As with most types of plastic, LDPE can leach chemicals that may pose a long-term risk to our health.
Similar to PVC, whether LDPE is recyclable or not will have to depend on your local recycler.
Type 5: Polypropylene (PP)
Polypropylene, or PP, is a rigid thermoplastic derived from petroleum and is among the cheapest plastics available today. It is one of the lightest polymers among all commodity plastics, which makes it suitable for lightweight applications.
Moreover, it has excellent resistance to diluted and concentrated acids, alcohols and bases, and can withstand environmental stress cracking, but it is a highly flammable material.
Despite this, it is not recyclable.
- Packaging applications: flexible packaging and rigid packaging
- Consumer goods, such as furniture, houseware, appliances, luggage, toys, etc.
- Automotive applications, such as battery cases, door trims, bumpers, etc.
- Fibres and fabrics, such as rope and twine
- Medical applications (due to high bacterial resistance), such as disposable syringes, medical vials, Petri dishes, intravenous bottles, pill containers, specimen bottles, etc.
Despite it being one of the cheapest plastics, it’s worthwhile to note its limitations. For one, it has poor resistance to UV, impact and scratches and its heat-ageing stability is affected when in contact with metals.
However, despite its chemical limitations, it has not been considered as one of the toxic plastics in the category.
Type 6: Polystyrene (PS)
Polystyrene is a hard thermoplastic available both in the typical plastic form as well as in the form of rigid foam, commonly referred to as “styrofoam”.
The material is somewhat controversial amongst environmental groups as it is one of the most obvious forms of plastic found as litter, either in waterways or the ocean.
Polystyrene is not recyclable.
- The solid plastic form of polystyrene is used in items such as yoghurt tubs, plastic disposable cups, CD cases, as well as medical devices such as Petri dishes and test tubes
- Styrofoam is most commonly used as packing material (i.e., the foam-like material when you unbox a new television), packing peanuts, and as disposable to-go containers
As polystyrene is inert (it does not react well with acidic or basic solutions) it will last a long time in the environment, which poses as a litter hazard as these items are usually disposed of after a short while.
As with other types of plastic, it has the potential to leak chemicals under heat, which is a risk to human health if exposed.
Type 7: Other
Type 7 plastic includes miscellaneous plastic, such as polycarbonate, polyctide, acrylic, styrene, fibreglass and nylon.
Plastics in this category are also non-recyclable.
Many BPA products also fall into this category. Although the health effects of BPA remain unconcluded, it’s best to avoid using plastic from this category, especially for food products!
BPA, or bisphenol A, is a chemical added to many commercial products such as food containers and hygiene products.
According to Healthline, excessive exposure to BPA may cause infertility in men and women, it is linked to heart disease and Type 2 diabetes, increases the risk of obesity and may cause other health problems such as asthma, worse immune function, and impaired thyroid function.
- Baby bottles
- Sports equipment
- Medical and dental devices
- CDs and DVDs
We have managed to surround ourselves with plastic for the past 40 years, yet it is also a fact that some of us do not understand plastics that well.
However, it’s true that recently consumers and public health experts have been expressing more concern about the potential health effects of our exposure to plastic.
One thing the last several years has taught us is that plastics is that the chemicals used to manufacture plastics can leach into the food we are eating.
A study by Zimmermann et al. (2019) analysed 34 everyday plastic products made of eight types of plastic to investigate the presence of toxicity and they discovered that 74% of the products tested were toxic in some ways.
In the products, over 1,000 chemicals were detected in the plastics, yet 80% of them remain unknown. This emphasizes the fact that many of us may not understand the full breadth of the safety of chemicals found in plastics.
Well-known examples of hazardous chemicals include BPA (found in plastic water bottles, plastic storage containers, thermal paper receipts and food can linings) as well as phthalates, typically used to make PVC plastics more flexible.
The Plastic Waste Problem
With the millions of plastic products available and increasing production of plastic products to meet our demands, it stands true that plastic waste is a serious problem, especially with the lack of a comprehensive recycling system that encompasses all seven types of plastic.
More needs to be done to address this.
As a social enterprise pushing the boundaries of sustainability and social innovation, we’re proud to have Beyond Bins on board to champion our efforts in creating a circular economy.
By looping in plastic waste (specifically, Type 2 and 5) and the underserved communities, we create a system where nothing is left behind.
As consumers, we vote with our wallets.
It’s crucial that we exercise choice where we can to let others be aware of sustainable and innovative solutions instead of producing more waste.
Zhi Yee writes for Biji-biji Initiative a partner organization of Waste or Create hub She is a biology/ecology graduate with experience in sustainability programming, research, and educational programs.ZHI YEE TEH