Crosslinking of fluoroelastomers and the influence on final properties
Matthias Lueckmann*, Wolfgang Steinhoff, DuPont de Nemours (Germany) GmbH
Crosslinking of rubber materials generates chemical bonds between chain segments and forms a stable three dimensional structure. The properties of uncured rubber are changing from more viscous behaviour with high remaining deformations to high elastic deformation behaviour after crosslinking that minimizes the irreversible flow. As specialty rubbers like FKM and AEM are used in demanding environments, the crosslinking process is important to provide materials that can withstand e.g. high temperatures. At current, fluoroelastomers are cured with crosslinking systems based on bisphenol or a combination of peroxide with coagent. Crosslinking mechanisms will be presented as well as efficient designs to control rate and state of cure. In addition, the appropriate final properties of the elastomers will be discussed. Regarding the crosslinking with bisphenol, the influence of polymer structure and metal oxides will be shown.