Abstract: A method for combining materials (such as impregnating materials with functional materials) uses a combination of supercritical fluid technology and polymer melt processing technology. The functional material is soluble in a near supercritical or supercritical fluid, which dissolves in the matrix/bulk material during melt processing. Controlling the processing conditions facilitates a change of state for the fluid, which results in the precipitation of the functional material in the bulk material. The impregnated bulk material may be shaped using conventional polymer based processing techniques such as extrusion and injection moulding.