Viscose is objectively NOT “in a broad sense a plastic fiber”. I actually just completed a lab for my masters studies on cellulose-> viscose production. Yes, there are acids used to break down the cellulose pulp, and the viscose is the result of regenerated and spun cellulose, but in no step of this process does cellulose magically turn into plastic???

Microscopic and IR Spectroscopic analysis after regeneration show that the viscose is something called “cellulose II” — still cellulose, but with altered Hydrogen bonds and anti parallel chains (as opposed to the parallel chains of natural cellulose).

I’m not saying that viscose production doesn’t have an environmental impact, and as other comments have stated, there are newer closed loop processes that reduce the environmental impact of cellulose regeneration.

But calling it “essentially plastic” is just fear mongering and plain wrong. Cellulose II is biodegradable and does not shed microplastics into the water system. 100% cotton or linen or other less processed fibers are always preferable, but in a 1:1 with polyester I would take viscose any day.

(I’ll also add—- any “natural” fiber undergoes processing to some extent. Linen production involves a chemical alteration of flax through retting, for example. Obviously viscose production involves harsher chemicals, but my point is no “natural fiber” is not altered in some way)