monomerele

Monomerele, or monomers, are the basic building blocks of polymers. In polymer chemistry, a monomer is a small molecule capable of covalently bonding to other monomer units to form a long chain or a three-dimensional network. Monomerele are typically organic and contain one or more reactive functional groups that enable linkage during polymerization.

Monomers vary by functionality. Monofunctional monomers have a single reactive site and tend to form linear polymers, while polyfunctional monomers have two or more reactive sites, which can lead to branching or cross-linking in the resulting material. They can undergo addition (chain-growth) polymerization, where monomer units add one by one to a growing chain, as seen in polymers like polyethylene or polystyrene. They can also undergo condensation (step-growth) polymerization, where small molecules are released during linkage, as in the formation of polyesters or polyamides.

Common synthetic monomers include ethylene, propylene, styrene, vinyl chloride, and acrylonitrile. In biology, monomers such as amino acids, nucleotides, and monosaccharides serve as the basic units of proteins, nucleic acids, and polysaccharides, respectively. These biopolymers enable essential biological functions and structures.

The properties of a polymer depend on the identity and arrangement of its monomers, as well as the polymerization conditions. Monomer selection allows copolymerization, cross-linking, and control over molecular weight and architecture. This versatility underpins a wide range of materials, including plastics, elastomers, resins, adhesives, hydrogels, and biomaterials.