MONOMERIEN

Monomerien are small, low‑molecular‑weight molecules that serve as the building blocks of polymers. They join through covalent bonds to form long chains or three‑dimensional networks. Most monomerien contain at least one reactive functional group, such as a carbon–carbon double bond or a heteroatom group, enabling polymerization. They may be synthetic or naturally derived.

Categories include vinyl monomers (ethene, propene, styrene, vinyl chloride) that undergo chain-growth polymerization, and cyclic or condensation-prone monomers used in step-growth polymerizations. Biopolymers arise from amino acids, nucleotides, and simple sugars. Monomer functionality, the number of reactive sites per molecule, governs architecture: difunctional monomers tend to yield linear chains, while multifunctional ones can produce branches or crosslinks.

Polymerization mechanisms include chain-growth and step-growth. Chain-growth rapidly adds monomer units from an active center, e.g., ethene to polyethylene or styrene to polystyrene. Step-growth forms bonds between all functional groups, often with release of a small molecule, producing polyesters, polyamides, etc. Crosslinking occurs when multifunctional monomers bond chains into networks.

Monomerien choice shapes polymer properties such as glass transition temperature, crystallinity, and mechanical strength. Bulky or rigid monomers raise Tg and stiffness, while flexible monomers yield softer polymers. Purity and processing conditions affect polymer quality; many monomerien are hazardous or highly reactive, thus controlled handling and stabilizers are common.