l Polyethylene is one of the most widespread polymers. Generally speaking, we usually encounter it in the form of a very thin film; however, it can be transformed into a solid foam by means of an industrial process. We can generally distinguish between chemically expanded materials, with a coarse cell that can be combined with one layer on top of the other to obtain thicknesses of a few centimeters, and physically expanded materials, with a very thin cell, impermeable to water and with a very wide range in terms of hardness and density, forming blocks a few centimeters high.

They can be cut into sheets, die-cut, cut with water jets, adhesified, shaped and milled, thus lending themselves to a multitude of uses, ranging from packaging to gaskets and seals, from thermal insulation to acoustic insulation, all the way to the creation of gadgets and displays.