write any two properties of plastics
Answers
Explanation:
What is Plastic?
Plastic is defined as a material that contains as an essential ingredient an organic substance of large molecular weight. It is also defined as polymers of long carbon chains.
Carbon atoms are linked in chains and are produced in long chain molecules.
Plastic was discovered by famous German chemist Christian Schonbein in 1846. Plastics were actually discovered accidentally. Christian was experimenting in his kitchen and by accident, he spilt a mixture of nitric acid and sulphuric acid. To mop that solution (a mixture of nitric and sulphuric acid) he took a cloth and after moping he kept it over the stove. After some time, the cloth disappeared and from their plastic got its name.
Introduction to Plastic
The word, plastic, was derived from the word ‘Plastikos’ meaning ‘to mould’ in Greek. Fossil fuels have compounds containing hydrogen and carbon (hydrocarbon) which act as building blocks for long polymer molecules. These building blocks are known as monomers, they link together to form long carbon chains called polymers.
Types of Plastics
Depending on physical properties, plastics are divided into two types: Thermoplastic and thermosetting.
Thermoplastic: Plastics that can be deformed easily upon heating and can be bent easily. Linear polymers and a combination of linear and cross-linked polymers come under thermoplastics. Example: PVC, nylon, polythene, etc.
Thermosetting: Plastics that cannot be softened again by heating once they are moulded. Heavily cross-linked polymers come under the category of thermosetting plastics. Example: Bakelite, melamine, etc. Bakelite is used for making electrical switches whereas melamine is used for floor tiles.
Recycling of Plastic
Recycling of plastic is very important. If they are not recycled at the proper time, then they get mixed with other chemicals or materials and hence become more difficult to recycle and become a source of pollution.
They are non-biodegradable, and they do not get decomposed by the microbial action.
To avoid this, it is important to use biopolymers or biodegradable polymers.
Properties of Plastic
Strong and ductile
Poor conductors of heat and electricity
Easily moulded into different shape and size
Resist corrosion and are resistant to many chemicals.
Answer:
(1) plastic is chemically unreactive; plastic do not react with air and water
(2) plastic are poor conductor of heat and electricity; they do not conduct heat and electricity, so they be used as insulators
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