I am not a chemist, or a specialist on polymer clay,
so forgive me if this is not entirely accurate.
Polymer clay is a manmade material that remains pliable for long periods,
but bakes or 'cures' in your home oven at a fairly low temperature.
Though hard/firm after curing, thin sheets are often flexible.
You can sculpt it, carve it, stamp it, texture it, sand it, buff it, paint it, and
build with it to create sculpture, accessories, figurines, dolls, or jewelry,
and/or use it to embellish other surfaces.
You can use polymer clay to make mosaics, plaques, wall hangings, furniture,
jewelry, household items, toys, decorations and just about anything you can imagine.
In recent years, polymer clay has changed from "a child's plaything"
into an artistic medium, yet its delightful playfulness has not been lost.