Polymers aren't just big molecules—they're chains where tiny monomers link up hundreds or thousands of times, each addition step changing the material's strength and melting point. Drag the slider to grow the chain and watch the degree of polymerisation climb.
Chain BuilderADDITION MODE
Drag slider to add monomer units to the growing chain
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Addition polymerisation occurs when monomers containing carbon-carbon double bonds (C=C) join together without losing any atoms, with the π-bond breaking to form new σ-bonds between successive monomer units. Classic examples include ethene forming polyethene, styrene forming polystyrene, and vinyl chloride forming PVC—all proceeding via radical or ionic chain mechanisms that propagate rapidly once initiated. The polymer chain grows by sequential addition of identical monomer units, preserving the entire molecular structure of each monomer in the final polymer backbone, which means the empirical formula of the polymer matches the monomer exactly. This mechanism is characterised by three distinct stages: initiation (radical or ion formation), propagation (rapid chain growth), and termination (chain-end coupling or disproportionation).
Know This
The degree of polymerisation is the average number of monomer units in a polymer chain, directly controlling molecular mass and critical mechanical properties like tensile strength and melting temperature.