Plastics are everywhere! Anytime you open up a coke bottle or your favorite snack, you are using packaging made from plastic. Even the car you drive contains plastics. Plastic is preferred over many other alternatives because it is sustainable, lightweight, and shatter-proof. These properties make the everyday goods you use cheaper and more versatile. Although all plastics seem to look the same, there are actually 7 main types. Let’s take a look at each of these!
PETE or polyethylene terephthalate is a common plastic used in a variety of applications, including the food and beverage industry. The material was invented by John Whinfield and James Dickson of Calico Printers in 1941.
In order to remain tasty, soft drinks need to retain their carbonated flavor (or fizz) for as long as possible. Since PETE is impermeable to both gases and moisture, this material is used for all the soft drink bottles.
Besides soft drink bottles, PETE can be found in medicine packaging as well. You might have noticed that many over-the-counter medicines often come in plastic packaging with an aluminum layer underneath. These are blister-packs made of PETE.
Since PETE also has a high melting temperature, it can be used in food trays that need to be heated. In addition to food packaging, other materials, such as clothing and flooring, are also made from PETE in the form of polyester.
HDPE, or high-density polyethylene, is used in a variety of applications. It is called “high-density” because the plastic has a high-density to strength ratio. Unlike PETE, HDPE cannot be used to hold soft drinks because it lacks a barrier to prevent gases from escaping. Instead, HDPE is used to create bottles in blow-molded form to hold drinks such as milk and orange juice. The plastic is also used to package foods such as cereals and other snacks. Since HDPE is not susceptible to chemical reactions, items such as soap detergents and bleach are stored in bottles made from HDPE.
If you have gone to construction sites or examined your sprinkler system, you may have seen thick white piping. This is another form of plastic called Polyvinyl Chloride or PVC. Because of its hardness, PVC is used in numerous applications ranging from plumbing to healthcare.
Its ability to prevent penetration by bacteria and chemical agents make it an ideal and less costly solution for transporting water. Its fire resistance also enables it to be used in electrical cables. Unfortunately, a fire will cause HCl gas to be emitted, making this cable hazard to use in common areas. Other applications include catheters and blood-collection containers in the medical field.
Low-density polyethylene was created in 1933 by Imperial Chemical Industries. Unlike HDPE, its strength is lower and is most commonly seen in thin film form. LDPE is used to make thin plastics including grocery bags, as well as thin containers for keeping bread and fruits. Since it is not as hard as HDPE, LDPE is ideal for packaging that requires high flexibility such as squeeze bottles. This is why bottles for items such as shampoo and lotion are made from LDPE. This plastic is also used in juice and milk cartons to enhance water resistance.
First created in 1951 by Philips Petroleum scientists, Polypropylene (PP) is a plastic with a high heat tolerance. Since it has a high melting point, plastic bottles made from this material can hold hot liquids without getting deformed. Its heat and resistance to chemical absorption make it an ideal application for containers used in laboratory equipment. This also makes it ideal for food containers that get put in the dishwasher. The plastic is also known to be tough and shatter-proof which makes it ideal for use in bottle caps. Besides containers for food, PP is also used in materials for carpets and rope.
Found in 1839 by Eduard Simon, polystyrene (PS) is one of the most widely used plastics in the world. It has excellent properties such as a low melting point that allows it to be shaped relatively easily. PS exists as tough plastic sheets and foam. As a result, polystyrene enjoys a variety of applications including foam cups, plastic eating utensils, plastic CD cases, and yogurt containers.
Since it is widely used, plastics with PS tend to fill landfills and oceans. It has generated a lot of controversy and some cities have banned its use in certain applications.
In addition to the plastics mentioned, other forms of plastics exist, like Nylon and PMMA (poly methyl methacrylate). Nylon is commonly used for clothing while PMMA is a shatter-resistant alternative to glass.
Plastics are one of the most widely used materials in the world. They are used in a variety of applications including food and liquid containers, packaging, and clothing. Plastics do indeed make the world go round!