Trommsdorff effect
The Trommsdorff effect , also known as the Trommsdorff-Norrish or gel effect , is the increase in the reaction rate observed in polymerization reactions at high conversions .
The reason for this effect is the decreasing probability of chain termination through recombination of the reactive chain ends; this is caused in particular by the increasing immobility of the growing polymer chains. The resulting increasing speed of the exothermic reaction causes a rise in temperature, whereby the decomposition of the radical initiator is accelerated and the concentration of the reactive molecules increases. At the same time, the dissipation of the heat of reaction ( heat of polymerization ) is made more difficult by the increasing viscosity .
This phenomenon can lead to an explosion , which is why the reaction must be effectively cooled or, if necessary, also stopped.
The Trommsdorff effect is named after the German chemist Ernst Trommsdorff and the English chemist Ronald George Wreyford Norrish .
literature
- Bernd Tieke: Macromolecular Chemistry . VCH Weinheim, 1997.
Individual evidence
- ^ MD Lechner, K. Gehrke and EH Nordmeier: Makromolekulare Chemie . 4th edition, Birkhäuser Verlag, 2010, p. 71, ISBN 978-3-7643-8890-4 .