Fabric ID and problem cause

[roro]

See photos - What fibre is it in this curtain, and what do you think is the probable cause of the loose fibres

The fibre does not dissolve in sulphuric acid, formic acid or sodium hypochlorite. It shrinks quickly from flame but eventually will catch fire and burns quickly When extinguished there is a fairly hard, black bead.
Back of fabric

Front of Fabric

Problem

 

[Nate The Great]

The hardness of the black bead sounds like synthetic fiber to me.. As for being drapery, I'd lean towards sun degradation.. While I'm of no use as I've never had first hand dealings with drapery other than smelling OMS when I was 5years old watching my parents clean it..

How old is the fabric?

 

[Mikey P]

sun rot

 

[Cleanworks]

Sounds like acetate.

 

[Jim Pemberton]

Sounds like acetate.

Agreed.

Acetate is the only regenerated cellulose fiber that melts to a hard bead.

If you want to do a chemical test, it breaks down in acetone.

Sun damage is my guess.