[ajsgolf]

The piece in the pictures below came off the bottom of the kitchen sink. What is it for? Does it provide some kind of insulation or does it serve some other purpose? Do I need to be concerned? Can that bottom portion of the sink be replaced with a whole new piece?

 

[Old Thomas]

It makes the bottom of the sink less resonant, so putting things in the sink is quieter. If you are concerned, you could put on self stick sound deadened sold for cars.

 

[Nealtw]

It is just like a sound deadening thing

 

[huesmann]

Yup. Looks like you have quite a bit of peeling there. If your sink gets loud, you can just get something like peel-n-seal and slap it on the bottom and/or sides. Should stick just fine and provide plenty of sound damping.