Fillers

 
EPDM rubbers have an excellent capacity for high loadings of filler/oil. The rubber content in compounds is frequently as low as 25-30 %. Carbon black is the most commonly used filler in EPDM compounds. Here the reinforcing effect and processing behavior are combined in a especially advantageous manner, but EPDM can also accept high levels of light colored fillers.

The polymer grade and, above all, the molecular weight determine the filler loading that can be easily incorporated. Oil-extended grades have the highest molecular weights and are able to accept the highest filler loadings.

With the same molecular weight, polymers of higher ethylene content permit the use of higher filler loadings than do those of lower ethylene content.

 

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