What the strips are made of will depend on what the blower housing is lined with, if anything.
The strips are the replaceable wear item in the assembly.
Some part will always wear out before the other, and the strip is the cheapest and easiest thing to replace ,relatively speaking.
Obviously the nylatron has a temp it should not be taken above, like any plastic type material, even though it is really not plastic.
From past experience machining this stuff I know it will not cut well unless your tooling is razor sharp or a ground and polished type tool.
This tells me it has a high amount of resistance to wear if you can't even get it to cut properly unless the set-up and cutting conditions are perfect.
You can take a solid round bar of nylatron and smash it with the ball end of a ball peen hammer and barely leave a mark, this tells me that the material is not easily compressed.
There are probably other materials that would work too, but under the normal operating conditions of the blower this stuff works best and the right price for the manufacturer.
If something else held up longer or gave a better seal and was harder too manufacture the material may not even be considered.
This may even be a plastic injection molded part too.
I've never seen one in my hand so some of that is speculative.
Anyone got a picture of one close up??