Layered foams : A new class of cellular polymers

A novel process is described for making integral multilayered polymers with the layers separated by discontinuous narrow gaps containing air and/or a blowing agent. The two step process involves first introducing a low degree of entanglement among some of the polymer chains and then breaking apart these entanglements using a blowing agent to give the discontinuous gaps that resemble elongated, narrow cells. The layer density can be controlled...