Types of plastics
There are two main types of plastics: thermoset and thermoplastics. Thermoplastics are plastics that can be re-melted and re-moulded into new products and, therefore, recycled. However, thermoset plastics “contain polymers that cross-link to form an irreversible chemical bond,” meaning that no matter how much heat applied, they cannot be re-melted into new material and hence, non-recyclable. Breaking these plastics further down, you can see the everyday uses of each type in various ways.
PET or Polyethylene terephthalate: It is usually used in food storage containers and water bottles.
PVC or Polyvinyl chloride: it is brittle but stabilisers are added to it. This makes it a softer plastic that’s easy to mould into various shapes. It is commonly used in plumbing applications because of its durability.
Polyvinylidine chloride (PVC): Commonly known as Saran, this plastic is used in wraps to cover food. It is impermeable to odours from food and can be drawn into various types of films.
Polytetrafluoroethylene, also known as Teflon: it was first manufactured by DuPont in 1938, it is a heat-resistant form of plastic. It is very stable and strong and creates a surface that is almost frictionless.
Polypropylene: Also called PP, this plastic has various forms and is used in many applications, including tubes, car trims and bags.
Polyethylene: Its initial uses were for electrical wires but it is now found in many disposable products, including gloves and garbage bags. It is also used in other film applications, such as wraps, as well as in bottles.
Expanded Polystyrene (EPS) or Styrofoam
EPS was invented by Dow Chemical scientist Otis Ray Mclntire in 1941. The process in making this envolve small beads of the polymer polystyrene are steamed with chemicals until they expanded to 50 times their original volume. After cooling and settling, the pre-expanded beads are then blown into a mould — such as that of a cup or any other container — and steamed again, expanding further, until the mould is completely filled and all of the beads have fused together. The finished product is a lightweight that is about 95 percent air, and you buy your takeaways, tea or coffee in them.