New Extrusion Process for Manufacturing Radial Functionally Graded Polymer Materials

摘要

Usually additives, fillers and reinforcing materials are homogeneously distributed in plastic profiles when they have undergone conventional extrusion processes. However, in many applications it would be advantageous to place these substances in sufficient quantities where required by the subsequent application of the profile. This is where functionally graded materials start from since they have no homogeneous composition or distribution of fillers along one dimension. These materials have different compositions along the part's cross-section based on its application. Nowadays functionally graded materials are already used in various material combinations, e.g. metal and ceramic, for special applications such as aerospace, nuclear energy and chemistry. The production of functionally graded materials on a purely polymeric basis is only possible under laboratory conditions or with discontinuous processes so far. For this reason, the SKZ is currently developing an innovative continuous extrusion process for radial functionally graded polymer materials. The produced round profiles of two polymers display a smooth radial transition between the two components over the part's cross-section and a homogeneous composition in the extrusion direction. This can be achieved by using a rotating mask in the melt flow, which forms a spiral layer structure and a subsequent concentric mixing by a rotating cluster in the flow channel.