Hello Michael,

i would expect that fillers can have an influence on ageing behaviour. The general interaction between the polymer and present media will remain the same but with fillers you get additional effects. Depending on the dispersion and dimensions of the filler the volume of unaffected polymer might become rather small.

Some aspects i would keep in mind:

- fillers can absorb light and therefore the penetration depth might change with filler content

- the diffusion of substances can be influenced by fillers. with high filler content the diffusion path might increase and therefore again the penetration depth respectively concentration profile over the seal might change.

- if an active filler is applied there will be an interfacial layer between polymer and filler particles which might have different properties

- the filler or other components might act as catalist for certain reactions

I hope this short list gives you some useful information.

regards

Matthias

It depends on the filler and the main degradation process. E.g. if the filler absorbs UV-vis it can slow down the photooxidation.

Hello Michael,

i would expect that fillers can have an influence on ageing behaviour. The general interaction between the polymer and present media will remain the same but with fillers you get additional effects. Depending on the dispersion and dimensions of the filler the volume of unaffected polymer might become rather small.

Some aspects i would keep in mind:

- fillers can absorb light and therefore the penetration depth might change with filler content

- the diffusion of substances can be influenced by fillers. with high filler content the diffusion path might increase and therefore again the penetration depth respectively concentration profile over the seal might change.

- if an active filler is applied there will be an interfacial layer between polymer and filler particles which might have different properties

- the filler or other components might act as catalist for certain reactions

I hope this short list gives you some useful information.

regards

Matthias

Polyisoprene contains C=C bonds in each of its constitutional repeating units right in the middle of each CRU. As such, it is susceptible to oxidation & ozonolysis. Vulcanization improves the polymer's properties towards these effects & well-dispersed filler acts as a mass transport barrier to oxygen & ozone. Therefore, ageing properties will be affected positively.

Many thanks to everyone that answered. Are they any studies that have been performed in the past to show the degradation characteristics of inert silica filled polymers (preferably in poly-isoprene)?    Thanks