I know that PVC is PolyVinylChloride. My windows are made of just “vinyl” but they feel and look exactly like PVC. What is the difference, if any between these two materials?
The base plastic is the same. “Vinyl” is generally thought of as a flexible material because it has plasticizer chemicals mixed in - that’s the classic “new car smell”. PVC water pipe and your window frames are more rigid because of filler materials mixed in; kinda like adding rocks to cement to make concrete.
BTW - the molding of PVC is somewhat hazardous. There is outgassing of overheated chlorine compounds which are also corrosive. PVC molds are usually stainless and PVC parts are often produced in dedicated shops with good ventilation and/or “sacrificial” machinery.
Well, PVC doesn’t have to be rigid at all, as exemplified by PVC clothing which was (almost) fashionable in the 1960s/70s, and according to wiki retains some popularity today.