Raju’s classmates wanted to know about plastics. They asked their teacher what types of plastics were used on a daily basis.
Teacher said: “Well, plastics are synthetic materials made from organic polymers. These materials are easy to mould when soft and retain the shape. Basically plasticity is the ability of a material to deform without breaking. The ability to be moulded into any shape of unbreakable nature which is lightweight makes plastic a very popular material.”
Most plastics are non toxic and are not affected by a wide range of chemicals and water. That is why it is commonly used in making packaging and piping materials. Its non conductive property makes it the best material for electrical fittings.
One can find plastic being used in the making of cases for TV sets, washing machines, laptops, computers, buckets, furniture like chairs and tables, toys, car interior parts, packing bags, bottles, raincoats, window frames, electrical panels and fittings, etc. Look around and one will find plastic everywhere including one’s pens and refills. Plastic is available in various colours too.
Smita got up and asked: “Are all these articles made of the same plastic or are there different kinds of plastics for different articles?” The teacher explained that there are different types of plastics for different uses. Some of the common plastics are PET, HDPE and LDPE.
PET (Polyethelene Terepthalate ) are mostly used to make food bottles, containers, ropes, etc. HDPE (High Density Polyethylene) is used to make containers for shampoos, oils, detergents, food oils, etc. HDPE containers if not originally used for food items should not be reused for storing food items. LDPE (Low density Polyethylene) is very flexible and widely used in grocery bags, carry bags and cling film for food items. PVC (Polyvinyl Chloride) is used for different types of plumbing pipes, hoses, and hose and pipe fittings. All of these plastics can be recycled.
Some other types of plastics are nylons and polyesters that are used in fabrics; polycarbonates that are used in CDs and eye lenses; and polystyrene that is used in food containers and disposable plates, cups, etc.
(Writer is a mechanical engineer and runs a hands-on science activity centre at Margao)