Answer to Question #260555 in Material Science Engineering for Sanju

Question

Look at your surroundings and select a material on your choise and write a note about it

Answer 1

Plastic is a polymer just like synthetic fibers which can be molded into desired shape and size when soft and can be hardened to produce durable articles. The term ‘Plastic’ was derived from the word ‘Plastikos’ which means ‘to mould’ in Greek, and it is used to refer to a wide range of semi-synthetic or synthetic organic polymers. Different types of plastics are known to possess different physical and chemical properties. Many articles like chairs, tables, buckets, toys, balls, etc are made of plastic material.They are light in weight and are chemically stable.Easily moulded into different shapes and sizes.Good insulation and low thermal conductivity.Good impact resistance and they do not rust.Good transparency and wear resistance.Poor dimensional stability and can be easily deformed.Low processing cost.Plastics are of Two Types. They are: Thermoplastics, Thermosetting Plastic. The term ‘thermoplastic’ refers to plastics that do not undergo any chemical changes when subjected to high temperatures. These plastics do not undergo any changes in their chemical structures and chemical compositions when subjected to heat and can be changed into a soft state and remolded multiple times. Examples: Polystyrene, Teflon, Acrylic, Nylon, etc. They are also known as thermosets, and are plastics that can be molded only once and do not change shape on applying heat. These plastics can only be molded once and they cannot be softened on further heating. These plastics undergo degradation and become damaged when exposed to a large amount of heat. Examples: Vulcanized rubber, Bakelite, Polyurethane, Epoxy resin, Vinyl ester resin, etc. PolyethyleneIt is one of the most commonly used thermoplastics in the world. The primary application of polyethylene (polythene) is in packaging. It is often used to make plastic bags, bottles, plastic films, containers, etc. They exhibit strong creep when placed under a persistent force.The mechanical strength of polyethylene is comparatively lower than other plastics.They are very good insulators of electric current.The rigidity and the hardness of the polymer are relatively low.They exhibit strong creep when placed under continuous force.