Question

Thermoplastics are:
(a) linear polymers
(b) soften or melt on heating
(c) molten polymer can be moulded in desired shape
(d) All of these

Answer 1

If you have thoroughly gone through all the polymers and their monomers and properties, then you can easily answer what thermoplastics are.
Complete step by step answer:
- First of all, we should know what polymers are actually polymers. Polymers are the high molecular mass compounds, obtained by joining together a larger number of simple molecules through covalent bonds in a regular manner.
- The simple molecules which combine to form a polymer are called the monomers and this process of formation of the polymers is known as the polymerization and those polymers which are formed by the combination of two or more different monomers are known as the co-polymers.
Now considering the statement as;
- The polymers which can be easily softened repeatedly when heated and hardened when cooled with little change in their properties are called as the thermoplastics and it comes under the category of the linear polymers.
- The intermolecular forces in these polymers are intermediate between those of the elastomers and the fibers and there are no cross-links between the chains.
- Common examples of thermoplastics include polythene, polystyrene, polyvinyl chloride, Teflon etc.
So, Thermoplastics are linear polymers , soften or melt on heating and molten polymers can be moulded in desired shape.
Thus, option (d) is correct.

Note: Linear polymers are those polymers in which the monomeric units are linked together to form long and linear chains and are well packed and therefore, have high densities, high tensile strength and high melting points.