Synthetic Fibres and Plastics - II

Both thermosetting plastics and thermoplastics have almost the same tensile strength and durability.
Both thermosetting and thermoplastics are non-biodegradable but thermoplastics can be recycled but thermo setting plastics cannot.
The main difference between the two is that thermosetting plastics once set cannot be moulded again, but thermoplastic can be remoulded on heating. 

The 4R principle refers to the wisest usage of the available resources. It does not deal with production or development of more resources. So, the correct option is 'Reduce, Reuse, Recycle and Recover'. 

Plastic materials, if taken in by cows choke their wind pipe and make it difficult for them to breathe. Since it cannot be digested, then it cannot affect their digestive or excretory system in the way it affects the respiratory system. 

Polyvinyl chloride can change its shape on heating. But we know that thermosetting plastic does not change its shape on heating. So, polyvinyl chloride cannot be an example of thermosetting plastic. 

 Thermoplastics are the plastics, which are easy to recycle and reuse as they change their shape on heating. Also they can be dyed to give various colours so, the statement 3 is the characteristic property, which is not     possessed by thermoplastics. 

 Thermosetting plastics are formed by sharing of electrons. It means that they form a covalent bond between their sub units. Covalent bonds of  their sub-units are very strong. This makes thermosetting plastic a strong cross linked molecule, which becomes hard to break, even by heating. 

Bakelite is a poor conductor of both heat and electricity. So, it is used to make switches and utensil handles. 

Thermoplastics melt down easily on heating and can be moulded to give various shapes. It means that they can be deformed easily and are not rigid. 

Non-stick coating on cookware should be made of such a material that it neither reacts with oil nor allows the oil to stick over it. Teflon possesses both these properties. That is why it is used for coating cookware. 

Plastics are bad conductors of heat. So, they are used for the said purpose.

Chemicals and pickles need to be stored in such vessels, which are non-reactive. If they react, the chemical nature of chemicals and taste of pickles would be spoilt. Plastics are non reactive and thus are used for the same.

 Handles of screw driver and tester should be made of such materials, which don't allow the current to pass through them. Otherwise we may get an electric shock. Plastics are bad conductor of electricity. 

 Electricity wires carry the current along their path. They need to be covered with such materials, which do not allow the current to pass thorough to avoid any accident when touched. The material thus used for this purpose should be a bad conductor of electricity. As plastic is a bad conductor of electricity therefore, it is used for the same purpose. 

 Teflon is non reactive towards oil. Plastics and polystyrene melt down, if they catch fire. Melamine is resistant to fire and therefore, it is known as fire proof plastic. 

Electric plugs, switches etc. should be made of such materials, which neither allow the heat nor the current to pass through. Also, they should not melt down on heating. Thermosetting plastics possess these properties. Therefore, they are used for the same purpose. 

Plastics are very useful but they do not get decomposed by microbial action, which causes many problems. It means that they are non-biodegradable.

 Environment friendly materials are those, which are easily decomposed by the bacterial action. Paper, wood and cotton clothes are decomposed into simpler substances by bacterial action. Plastic bags are not decomposed and thus are not eco friendly. 

 Decomposition refers to the breakdown of complex substances into simple ones. Different substances take different time period for the same process. Vegetables and fruit peels take about a week or two for  the same, while cotton and woollen clothes take longer. But, paper will be decomposed within a few days only. 

 Melamine exhibits the unique property of resistance to fire. Fire men's uniform should be made of such materials only that it does not catch fire. 

Non-biodegradable substances are the ones which cannot be broken down further into simpler substances by natural processes. Tin, aluminium and metal cans possess the same property and thus, are known as non-biodegradable substances. Such substances are hard to dispose of. Hence it is advisable to minimize the use of non-biodegradable material.

Plastics cannot be decomposed by microbial action. Tin and aluminium are metals and the same is true for metals also. Woolen clothes are obtained from natural source and thus, are biodegradable. 

Recycling means that the substance is moulded in one or the other way and is used in some alternate way. Plastics and metals can be recycled in various ways, while cotton clothes once used can be reused but cannot be recycled. 

Jute and cotton are natural fibres, and they get decomposed into simper substances but plastics do not get decomposed. So, plastic bags are non biodegradable, while jute and cotton bags are biodegradable. 

 Eco friendly practices lead to a safe environment by wise use of resources. Keeping lights on, when not in room does not lead to a proper use of resources and thus not eco-friendly. Plastic being non biodegradable should be avoided and should not be thrown in water bodies.