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Free-radical polymerisation template
Free template. Download it, or open it in MolDraw to change it first.
AIBN loses N₂ to give two 2-cyanoprop-2-yl radicals, which add to styrene; the benzylic radical adds monomer after monomer and two chains end by combination or disproportionation.
Mechanism step by step
Initiation, propagation and termination of styrene with AIBN: every arrow moves one electron
- Initiation 1 – AIBN splits on heating, losing N₂ (benzoyl peroxide breaks its O–O bond the same way)
- Initiation 2 – The initiator radical adds to the CH₂ end of styrene
- Propagation – The benzylic radical adds the next monomer, again and again
- Combination – Two chain radicals pair up: one long chain
- Disproportionation – One radical takes a β-H from the other: an unsaturated and a saturated chain end
Key points
- Fish-hook arrows move one electron each; propagation keeps the number of radicals.
- Monomer adds head-to-tail: the new radical is the more stable benzylic (or α-ester) radical.
- Chains grow in seconds; high polymer is present from the start, while conversion rises slowly.
- Polystyrene ends mostly by combination, PMMA mostly by disproportionation; O₂ inhibits the chain.
Drawn with 167 atoms, 22 arrows, 13 shapes – every one editable in MolDraw.
Sources
How to use this template
- Press Edit in MolDraw. The template opens on the canvas of the free MolDraw editor.
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Frequently asked questions
Is the Free-radical polymerisation template free?
Yes. The Free-radical polymerisation template is one of the free MolDraw templates: open it in the editor or download it from this page as SVG or PNG and use it in your slides, worksheets and notes.
Can I edit the Free-radical polymerisation template?
Yes. It opens as an ordinary MolDraw drawing, so every structure, arrow, label and colour can be changed, and you can add your own content around it.
Is the chemistry checked?
Every structure is checked with RDKit and every curly arrow passes MolDraw’s electron-flow audit. The sources used are listed on this page.
Do the polymer templates show repeat units?
Yes. Each polymer is drawn with its repeat unit in brackets with n, next to the monomers it comes from.