CNN.com article "New fabric touted as radiation-proof"

It sounds a bit like the polyethylene that was used out on the ISS. It
does work to some extent- it cuts the radiation by a few percent, and
weighs comparatively little, but apparently it doesn't work as well as
was hoped.

Still, the types of radiation found in space are a little different from
that found on the ground- cosmic rays tend to be much higher energies;
so it may be far more useful and effective down on the ground.