In which classes, the polymers are classified on the basis of intermolecular forces ?

Explanation

On the basis of intermolecular forces of attraction operating between the different polymer chains, polymers are classified into the following four classes.
1. Elastomers 2. Fibres 3. Thermoplastics and 4. Thermosetting plastics.
1. Elastomers. These are rubber like solids with elastic properties. In these polymers, in the polymer chains are held together by the weakest, intermolecular, forces. These weak binding forces permit the polymer to be stretched: Examples of elastomers are buna-S, buna-N, neoprene etc.
2. Fibres. These are thread forming solids which posses high tensile strenght and high modulus. These properties are due to the strong intermolecular forces of attraction like H-bonding. These strong intermolecular forces of attraction lead to close packing of chains arid thus impart crystalline nature. Examples of fibres are nylon-6, nylon-6 6, polyester(teryļene) etc.
3. , Thermoplastic polymers. These are linear or slightly branched long chain molecules. These are capable of repeatedly softening on heating and hardening on cooling. These polymers possess intermolecular forces of attraction inermediate between elastomers and fibres.. Some common thermoplastics are polyethene, PVC, polystyrene etc.
4.Thermosétting polymers. These polymers are cross-linked or heavily branched molečules. These are supplied in partially polymerised form, which on heating undergo extensive cross-linking in moulds and become infusibles. These cannot be recycled. Examples are bakelite, urea formaldehyde resin etc.