Monomeres

Monomeres, or monomers, are small molecules that can covalently bond to other monomers to form polymers. They are the basic building blocks of polymers used in plastics, fibers, and biopolymers. A monomer typically contains at least one reactive functional group that enables bond formation, such as a carbon double bond, an amine, a carboxyl, or a hydroxyl group.

Polymers are produced by polymerization, which can proceed by addition (chain-growth) or condensation (step-growth). In addition polymerization, monomers with unsaturated bonds (for example ethylene, propylene, styrene) add to a growing chain with little or no byproduct. In condensation polymerization, monomers with complementary reactive groups join while releasing small molecules like water or methanol (as in polyesters and polyamides). The choice of polymerization mechanism influences molecular weight, structure, and processability.

Common biological monomers include amino acids (proteins), nucleotides (nucleic acids), and monosaccharides (polysaccharides). Common synthetic monomers include ethylene, propylene, vinyl chloride, and acrylate or methacrylate derivatives. The properties of the resulting polymer depend on the monomer’s structure and functionality, as well as how the units are arranged (stereochemistry, branching, cross-linking) and the degree of polymerization.

Monomer design affects material performance, including melting point, strength, flexibility, solubility, biodegradability, and processing characteristics. The concept of monomers underpins polymer chemistry and materials science, guiding the development of plastics, elastomers, composites, and bio-based materials.