homopolimer

A homopolimer is a polymer composed entirely of one type of repeating unit, derived from a single kind of monomer. This contrasts with copolymers, which contain two or more different monomer units in the same polymer chain.

Most homopolymers are formed by addition polymerization of vinyl monomers, giving repeated units along the backbone such as polyethylene from ethylene, polypropylene from propylene, polystyrene from styrene, and poly(methyl methacrylate) from methyl methacrylate. Other examples include polyvinyl chloride from vinyl chloride and polydimethylsiloxane from dimethylsiloxane monomers. Some homopolymers can also be produced by ring-opening or condensation polymerization, depending on the monomer’s chemistry.

The properties of a homopolymer depend on the nature of the monomer, molecular weight, tacticity (arrangement of side groups), and the degree of crystallinity. Polymers with defined stereochemistry, such as isotactic or syndiotactic forms, tend to crystallize and exhibit higher melting points and stiffness, while atactic forms are typically more amorphous and softer. Crystallinity, chain length distribution, and processing history influence mechanical strength, permeability, thermal stability, and optical properties.

In summary, a homopolymer is a single-monomer polymer with a wide range of practical materials and applications, from packaging and consumer plastics to specialized coatings and engineering polymers, depending on its chemical structure and physical form.