I think they are acrylic, or could be polycarbonate. The problem is not with the fusing together, that went just fine. The issue is the fumes released. And like the CSIs use, god forbid any fingerprints on the surface exposed to the fumes. You will get permanent white fingerprint marks on them. I learnt this the hard way when i made an acrylic knife holder for my kitchen.
I'm really apprehensive about trying to separate the sim and microsd, as long as the sim is working, i can get a new sim easily, get it activated by sms, and then destroying the old sim won't matter. But since it stuck better to the sd than the sim the first time, i'm afraid it'll just rip the outer plastic layer off, and probably damage the circuit too. And this is an expensive 128gb, but it was the thinnest, so...