05/06/2023
Letβs talk about plastic.
The word plastic is derived from the Greek (plastikos) which means capable of being shaped or moulded. It refers to their melleability or plasticity during manufacture that allows them to be cast, pressed,or extruded into a variety of shapes.
Plastics are inexpensive, lightweight and durable materials which can readily be moulded into a variety of products that find use in a wide range of applications.
They have replaced the traditional metals such as copper, brass, aluminum, silver and other alloys.
Classification of plastics & Nylon
1.) Thermoplastics
These consist of individual long chain molecules and do not undergo chemical change in the their composition when heated.
Any product made of these plastics can be re-moulded and recycled again and again
Examples of thermoplastics are polyethylene, polypropylene, polystyrene, polyvinyl chloride polypropylene and polytetrafluoroethylene ( PTFE)
2.) Thermoset
Thermoset plastics contain infinite three dimensional networks which is formed when the product is in the final form and cannot be broken down by reheating.
That is, Thermoset can melt and take shape once;after they have solidified,they stay solid forever.
CHALLENGES OF PLASTIC WASTE MANAGEMENT & ENVIRONMENTAL CONSEQUENCES
Many of the basic raw materials used in the mass production of polymers are toxic, e.g. pthalates, bisphenol A (BPA), tetrabromobisphenol,leading to air and water pollution.
Often, the plastic films popularly calledβnylonβ used for packaging pure water or shopping bags have become a nuisance in the urban areas where they block road, choke the drains or fly around. Some animals like goats and sheep swallow them with the feed and choked to death.
There are about 50 different groups of plastics, with hundreds of different varieties. This makes recycling very difficult (complexity)
A plastic bottle can take roughly one million years to degrade in the environment
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