Now that's interesting - I'm trying to decide on a secondary material for a strop I'm just making, and I've never heard of people using silk. I can get the "knobby" stuff from Thailand, so is it really thought of as that good?
I would suggest you make the silk strop and see how it works out. The denim strop I make seems to be working for me. I have no scientific data to prove that it is working. I just know that I am enjoying using it as well as the leather strop.