There are ecofriendly soundproofing panels as well. I'm really promoting this kind of products as it is ecofriendly. These are basically remolded from the plastics and it is called as Felt or Polyester Felt. If you looking for soundproofing material, please have a look such products. I'm sharing the post link below: https://www.linkedin.com/feed/update/urn:li:activity:6909361196081037312