Polymer – as the name stand, poly refers to ‘many’ and mer means parts. Polymers are the man-made artificial material which has occupied the major portion of the earth. The plastic bottle, carry bags, rubber tips of the earphone, natural rubber and silk are the common types of polymers seen around us.
Do you know that many proteins that constitute the human body are polymers? Naturally occurring polymer like biopolymer is found in the strand of our DNA. Polymers are also found to be naturally occurring in plants and animals.
Based on the occurrence, polymers are classified into three types
- Natural polymers
- Synthetic polymers
- Semi-Synthetic polymers
Based on the structure, polymers are classified into three types
- Linear polymers
- Branch chain polymers
- Crosslinked or Network polymers
Based on Mode of Polymerisation, polymers are classified into two types
- Addition polymers
- Condensation polymers
Based on Molecular Forces, polymers are classified into four types
- Thermosetting polymers
Elastomers are solid rubber-like polymers which are elastic by nature. Elastomers can be stretched to a certain extent on the application of the force. After the removal of external force/pressure, these materials retain back to their original shape without undergoing permanent deformities.
The most common example of the elastomer is the rubber band which is used to tie hair. When a little force is applied on the rubber band, it makes the band undergo elongation. Here the polymer chains are held by the weakest intermolecular forces, which allow the polymer to be stretched.
By removing the external tensile stress, the rubber band takes up its original form. This happens as we introduce crosslinks between the polymer chains which help it in retracting to its original position, and taking its original form.
Rubber is a common example of elastomers.
Physical and Chemical Properties of the polymers
- tensile strength of the polymer increased by increasing the length of the chain and cross-linking.
- Polymers only change from crystalline state to semi-crystalline state, but do not melt.
- Hydrogen bonding is seen in the polymers.
- Polymers with Van der Waals forces linking chains are known to be weak, but give the polymer a low melting point.
- High flexibility is seen in the polymers due to dipole-dipole bonding side chains.
To know further about elastomers, refer to the online learning application BYJU’S!