Monomeerien

Monomeerien, also called monomers, are small molecules that can undergo chemical reactions to form polymers. They are the fundamental units of polymer chains and determine many properties of the resulting material. A monomer contains at least one reactive site and may possess multiple functional groups that enable linking to other monomers. Through polymerization, these units join to form long macromolecules.

There are two broad classes of polymerization: addition (chain-growth) and condensation (step-growth). In addition polymerization, unsaturated monomers with carbon–carbon double bonds react to form a polymer chain, typically using initiators or catalysts. In condensation polymerization, monomers react with each other and release a small molecule such as water or methanol, forming bonds.

Common examples of monomers include ethylene, propylene, styrene, and vinyl chloride, which form polyethylene, polypropylene, polystyrene, and polyvinyl chloride, respectively. Natural monomers, such as amino acids, nucleotides, and simple sugars, serve as the building blocks for proteins, nucleic acids, and polysaccharides.

Monomers can be classified as homomonomers (one type) or comonomers (two or more types). The functionality of monomers—monofunctional, difunctional, or polyfunctional—affects the polymer architecture, including linear chains, branched polymers, or cross-linked networks.

Properties of polymers depend on the monomers used, their arrangement (random, alternating, block), molecular weight, and processing conditions. Monomers are central to materials science, enabling plastics, fibers, resins, and biopolymers with a wide range of properties.