Viscose, is like rayon, which is made from cotton & man made fibers. I wouldn't try it because when you wash & dry rayon, it shrinks & wrinkles, and in a funny way.

I got my silk pillowcase off of amazon for $20. Then I got my husband a satin pillowcase from Sally's for $5. So you might want to check those places out for an inexpensive satin pillowcase.
Hair: lots of fine 2c/3a
Length: Mid back
Shampoo:Shea moisture coconut hibiscus
Cond:, suave naturals coconut
Post condition/Leave in: Shea moisture smoothie
HG:L'oreal evercurl gel. AG: Recoil,