All elastomers have fundamental physical properties that lead to certain engineering limitations.
The main weakness with organic rubber (unlike silicone rubber) is its moderate resistance to environmental damage by heat, light and ozone.
Also, when cooled below a certain temperature rubber abruptly loses its elastic properties becoming very brittle and breaking into shards when struck (though the process is reversible). This is a property that it shares with many elastomers. (This critical temperature is the reason why winter tyres use a softer rubber than normal tyres.)
Finally, some rubbers are prone to "fluid uptake" whereby fluids dissolve the surface of the rubber and diffuse into the interior causing the rubber to swell and soften.
Of course, Primasil material technologists are aware the relevant factors when choosing the best compound for your product, and will work closely with you to achieve the optimum material.