Patent ID: 7632433

Claim:
A process for making a gradient material, comprising: employing a screw extruder system comprising material rate input conditions and operating conditions in conjunction with a given hardware element configuration, wherein the screw extruder system comprises a twin-screw extruder with segmented elements to influence a specific architecture of the gradient material; employing multiple feed streams of raw ingredients at variable, feed rates for compounding and extruding a final material in the twin-screw extruder; predicting a gradient architecture of the gradient material by utilizing one of time and volume residence distribution functions with a functional description of the disturbances; introducing disturbances into at least one of the multiple feed streams by altering at least one of the material rate input conditions and the operating conditions, in conjunction with the given hardware element configuration, wherein said introducing disturbances comprises said raw ingredients are extruded while a first set of operation parameters are selected that lead up to steady state conditions, which run at a hold time, upon which the process is disturbed to a second set of operation parameters for a specific period of time before a return to said first set of operation parameters, which results in the final material, and wherein the disturbances are selected from at least one of the group of step disturbances, linear ramp disturbances, and non-linear ramp disturbances to form a compositional gradient as part of the final material; and producing the final material comprising the compositional gradient in an architecture of the final material, wherein said final material is the gradient material, and wherein the final material comprises a structure of at least two homogeneous materials separated by a continuous compositional gradient.