I am working on medical seals made from poly-isoprene. We just changed suppliers and I have an FTIR plus EDX and others techniques reports showing the old seal to contain 84% poly-isoprene and the rest are fillers and the new seal contains 99.6 poly-isoprene. The mechanical properties are the almost the same. Does the amount of fillers affect the ageing properties of poly-isoprene?
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.
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