15.14 Write the free radical mechanism for the polymerisation of ethene.

<p><strong>15.14</strong></p><p>The chain is initiated by free radicals, Ra•, produced by the reaction between some of the ethene and the oxygen initiator.</p><p><strong>Chain propagation</strong></p><p>Each time a free radical hits an ethene molecule a new longer free radical is formed.</p><p>Ra• + CH₂ = CH₂→ RaCH₂CH₂•</p><p>RaCH₂CH₂• + CH₂ = CH₂→ RaCH₂CH₂CH₂CH₂ •</p><p><strong>Chain termination</strong></p><p>Eventually two free radicals hit each other producing a final molecule. The process stops here because no new free radicals are formed.</p><p>Ra(CH₂)_m• + •(CH₂)_n Ra → Ra(CH₂)_m(CH₂)_nRa</p><p>Because chain termination is a random process, polyethene will be made up of chains of all sorts of different lengths.</p><p>&nbsp;</p>

0 Upvotes 0 Upvotes 0 Downvotes

• • Report Abuse
• Comment