Types of Plastic

ScienceStruck Staff Oct 25, 2018
Plastic has emerged as one of the most versatile materials for making a whole range of products. Here is a brief overview about the different types of plastic.
Nowadays, plastic is used for making various products, ranging from toys to spaceships. The versatility of plastic is due to its physical properties, like water resistance, relatively low cost and comparatively easy methods of manufacturing.
It has replaced most of the traditional materials, like wood, leather and glass. We all are familiar with plastic, and use it in various forms in our day-to-day life.

Classification of Plastic

As per the chemical structure, plastic is classified into various types; acrylic, polyester, silicone, polyurethane, and halogenated plastics. If classified on the basis of properties, which affect the product design, it can be categorized into; thermoplastic, thermoset, elastomer, structural, biodegradable, and electrically conductive.
Plastic can also be classified on the basis of method of production or physical properties. In short, there are various criteria for classifying plastic, and it depends on the ultimate use. However, for a common man, most of these classifications are irrelevant.

Types of Plastic and Recycling

Plastic is a material, which degrades very slowly. It is said that, it takes around 100 to 500 years for discarded plastic to degrade naturally.
So plastic recycling is promoted in almost all parts of the world. However, different types of plastic required different methods of recycling. There was no universal standard to classify plastic, which is used in various products. It was in 1988, the SPI (The Society of the Plastics Industry) designed the symbol code for plastic classification.
The symbol code consists of a triangle of arrows, inside which there are numbers ranging from 1 to 7. This symbol is embossed on plastic items, like pet bottles, yogurt cups, etc.
This is a uniform coding system, which helps both consumers and recyclers to differentiate the various kinds of plastic. Apart from that, it gives a clear idea about which plastic is used for manufacturing that product.
So the number coding system makes it easier to sort out different plastic items for recycling. The following are the different types of plastic, as per this coding system.
The coding symbols start with number 1 (i.e, a triangle of arrows with number 1 inside it). This plastic is polyethylene terephthalate (PETE) and is the easiest one to recycle.
Pet bottles, medicine containers and water bottles are made of this plastic, which can be easily recycled to fiberfill for winter coats, sleeping bags and life jackets and can also be used for making bean bags and furniture.
Those plastic items coded with number 2 are made up of a high density polyethylene (HDPE). This plastic is mainly used to make detergent and shampoo bottles and milk jugs. This type of plastic is recycled to make rope, pipes and toys.
Number 3 is assigned for those plastics, which are made of polyvinyl chloride (PVC). It is often used in shower curtains, window and door frames, plastic pipes, automotive parts, etc.
Number 4 goes to those plastic items, that are made of low-density polyethylene (LDPE). This is found in sandwich bags, wrapping films, dry cleaning bags and trash can liners.
Plastic items made of polypropylene (PP) are given the number 5. This plastic is used to make Tupperware, margarine tubs, microwavable bowls and bottle caps.
The next one is number 6, which is used to denote plastic made of polystyrene (PS), and is known as Styrofoam. This plastic is mainly used for making coffee cups, meat trays, peanut packages and plastic tableware. This can be recycled to make a rigid foam insulation and many other items.
Number 7 is assigned to those plastics which do not fall under the categories of 1 to 7. These are not usually collected for recycling, as it is difficult to recycle this type of plastic.
So, these are the different types of plastic, which are classified according to their use and prospects of recycling. Among them, the numbers 1, 2 and 6 are commonly collected for recycling; but numbers 3, 4, 5 are not recycled in a regular manner.
Plastic items without numbers are also not fit for recycling. So, you can reduce the use of plastic; or else, opt for those in category 1, 2 and 6.