Using the search function in the upper right of the screen, I got five pages worth of posts containing the word "tyvek". I'm tired, so I didn't sort out the thread or two that I remembered there being an extended discussion in. For shade, you want something with holes in it. You want air to move through it, so that the hot air goes away. Something impermeable to water isn't likely to let a breeze pass through. I'm also uncertain what causes it to get that weird fibery quality. I know Tyvek from envelopes, and if you pull the two sides apart the adhesive leaves one side disintegrating a bit. I have this feeling that abrasion, like moving against a support might cause this. But I'm not sure if that comes from some sort of experience, or if I made it up.
All that being said, it might do well as a tent.
The Lady with a Lamprey
"The powerful are exploiting people, art and ideas, and this leads to us plebes debating how to best ration ice.
Man, no wonder they always win....." Lonesomebri