I am considering purchasing a custom pillow and the poly poplin is much cheaper than the cotton poplin. Since it's online I'm am wondering how noticeable the difference is. I am also wondering if poplin has a shine to it.
The main difference is that one is made of 'poly' (likely polyester) and the other is made of cotton.
How notable the difference is depend on how the poplin is made and how they handled the threads from which they made the fabric and the fabric once made.
Mostly man made fibers are more smooth and shiny but it is not a given.
I own a bag made from recycled pet bottles and when you see it you would say it is rough cotton. I own fine cotton fabric which is shiny and smooth like polyester in the way it looks.
Cotton mostly feels better to the skin, not as likely to make you skin sweat.
So best go with the descriptions and pictures on the site.
The name of the fabric consists of 2 parts:
- the fibre
- the weave
"Poly" / "cotton" is the name of the fibre that is contained in the fabric. Cotton is a natural fibre commonly found in clothing. The name "poly" is very ambigious, because there are many different fibres with that name, like polyester, polyacrylic, polypropylene, and many more. All of them are artificial fibres and have slightly different properties.
"Poplin" is the name of the weave. It's a very basic over-under weave with vertical ribs. It's somewhat resistant to wrinkling. Depending on the fibre it can have a very smooth and shiny finish or an even and matte one.
If you want to use the pillow to lay your head on it, I suggest the cotton because it's more comfortable in direct skin contact. Cotton can absorb moisture like sweat and can be washed at high temperatures. If it's a decorative pillow or mainly used to prop up your back (no direct skin contact), you can go with the poly option. Poly fabrics are resistant to damage (for example by pets), but have a tendency to pick up bad odors and feel sweaty in direct skin contact.