Cellular solids combine the properties of the solid material that forms the cell walls and edges with the properties of the matter that fills the cells. This results in unique properties that for many applications are superior to the properties of the single-phase, solid materials. Presented herein, accordingly, are an apparatus and a method for the manufacture of cellular solids with predictable microstructure. The apparatus includes an internally hollow housing defining an extrusion channel, a cell-fluid feeding unit for injecting cell-fluid into the extrusion channel, a conveying element, and a mold or a surface. The method includes injecting cell-fluid into a plasticized matrix in the extrusion channel to form a plasticized foam and dispensing the plasticized foam through an exit port of the extrusion channel into a mold or on a surface.

A method for manufacturing sustainable products with a blown, foam structure, wherein a mass comprising at least natural polymers such as starch is passed under pressure into a mold cavity (4) or through a mold die, and the mass is heated in the mold in a manner such as to stabilize the foamed structure to form the product, wherein the method comprises prefoaming of the mass prior to injection in the mold. Preferably, the prefoamed mass is kept under pressure until insertion in the mold. The invention further relates to an apparatus to be used in said method.