CBSE Class 12-science Answered
Copolymer
When there are two types of monomers joining to make a polymer, that type of polymer is known as a copolymer. This is also known as heteropolymer. Two monomers can join in any fashion to make a polymer. Based on these joining variations, copolymers can be categorized as follows.
- If the two monomers are arranged in an alternative way, it is known as an alternating copolymer. (for example, if the two monomers are A and B, they will arrange like ABABABABAB)
- If the monomers are arranged in any order like AABAAABBBBAB, it is known as random copolymer.
- Sometimes each monomer can join with the same type of monomers, and then the two blocks of homopolymers can join. This type is known as block copolymers (ex: AAAAAAABBBBBBB).
Homopolymer
When a single type of monomer is polymerized to form a macromolecule, it is known as a homopolymer. In other words, there is one repeating unit. Polystyrene is a homopolymer where the repeating unit is styrene residues.
In homopolymer, one monomer repeats and forms the whole polymer. In contrast, in copolymers there are two monomers making the polymer.
Since there are various ways of joining the two monomers, there are different types of copolymers, but this type of variation of joining cannot be seen in a homopolymer.