why are ties made of silk and what other fabrics could be used?

I have ties made of cotton.

Scriptor

some unusual "fabrics".........

http://www.artealchemica.com/Tessuti.htm

Neckties are not all made of silk.  There are now polyester
silky-looking ties, and scriptor's cotton ones, and woollen ties, and
wool and silk mixed fiber ties, Atkinson (? Irish), which pretty much
covers the range of natural fibers fine enough to weave into a soft,
tie-able fabric.
Linen isn't good, because it wrinkles.  We won't worry about gimmick
ties made of a thin piece of wood.
It's style or what passes as such.  Silk can be woven in fine stripes
and brocade patterns better than wool or cotton, and maybe the
producers stick to silk because it seems up-market and they can ask a
higher price ....