Foamed articles and methods of making the same

An airbag bladder for an article of footwear, the airbag bladder comprising:

• a first sheet having a first side and a second side;
• and
• a second sheet having a first side and a second side, wherein the first side of the first sheet faces the second side of the second sheet, and wherein the first sheet and the second sheet are bonded together to form an internal cavity in a space between the first side of the first sheet and the second side of the second sheet, wherein the bond extends around at least a portion of a perimeter of the internal cavity,
• wherein at least one of the first sheet and the second sheet comprises:
• an outer structural layer comprising a first thermoplastic elastomeric composition in a foamed state;
• an inner structural layer comprising a second thermoplastic elastomeric composition in an unfoamed state;
• and
• one or more core layers disposed between the outer structural layer and the inner structural layer, wherein the one or more core layers are configured to prevent liquid carbon dioxide from infusing into the inner structural layer.

An article of footwear comprising:

• an upper;
• and
• a sole structure secured to the upper, wherein the sole structure includes an airbag bladder having a sealed wall defining an interior cavity, wherein the sealed wall comprises:
• a first structural layer comprising a foamed thermoplastic elastomeric composition, wherein the first structural layer is substantially opaque;
• a second structural layer comprising an unfoamed thermoplastic elastomeric composition;
• and
• one or more core layers disposed between the first structural layer and the second structural layer such that the second structural layer faces the interior cavity of the airbag bladder.