1. UV light H removed 1. Formation of cross-links between fatty acid molecules The carbon chain becomes a radical: INITIATION 2.

2. 3.dimerisation cross-linking TERMINATION

3. 2.PROPAGATION 4. peroxide group + H 6.TERMINATION

4. 2. 4. TERMINATION 5.oxidativecross-linking

5. 6. UV light INITIATION more radicals are formed

6. 3. 5. 8. Cross-links that may form as oils dry.

7. The are a range of possible radical induced reactions than can occur between fatty-acids and triesters to cause them to become cross-linked: consequently there are many possible products formed!