Control of Crosslinking (contd)

• Allophanate crosslinks can be easily broken at temperatures above 120oC (248oF)
• Biurets require much higher temperatures

• Partial replacement of difunctional by trifunctional curatives or isocyanates will result in more thermally stable chemical crosslinks
  • Trimethylolpropane (TMP)
  • Elastomer will exhibit reduced elasticity, lower creep, and less swelling in organic solvents
  • Tolonate HDT (Rhone Poulenc) will increase cross linking with less decrease of dynamics

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