Melamine foam

Its structure is a 3D network of very hard strands, when compared to the array of separate bubbles in a material such as styrofoam.

Being open-cell, it entrains countless air bubbles, giving it low thermal conductivity and thereby making it an effective insulator.

Naturally lightweight, melamine foam is also used as insulation for pipes and ductwork, and as a soundproofing material for studios, sound stages, auditoriums, and the like.

[citation needed] Recent research has highlighted that melamine sponges contribute significantly to microplastic pollution.

A study published in Environmental Science & Technology found that these sponges release over a trillion microplastic fibers globally each month due to wear and tear.