The burn test breaks down to two main branches, those that take off when lit and keep a flame or smolder going until they burn out the portion of fabric, and those that you light and they go out, light, go out. That would be not self-extinguishing and self extinguishing respectively.
If yours smelled like a burnt meat and kept a flame for a good time, then you've got acrylic. Probably. You also have to look at the remnants of the burnt bit....hard black blob or hard bead, lace-like ash, black ash, tan bead...they all indicate a different thing.
It takes a while to get the knack of burn testing. I frequently brush up by choosing a snippit on something that is labeled (new silk and old silk smell the same). You have to train your nose, so to say, to catch the funk of the smoke. Same thing with hot water testing Bakelite and Celluloid. I keep a button around of each to compare to if needed, since it's few and far between that I get the stuff.
Handy burn tip, needle nose plyers or medical scissor-like clamps do nicely to hold your snippit. Fingers, not so much.
Burn some pure polyester double knit sometime. Preetttyyyy.
Jenn