Smart blenders controllably form multi-component polymer melts into a wide variety of fine-scale structural arrangements that can be retained in extruded plastics. The machines operate on the principle of chaotic advection, a recent subfield of fluid mechanics, and have been used to produce cast film and blown film but can also be used to extrude sheet, rod, tubing, and other products. Because and structure of a composite material influences greatly additive diffusion, and matrix dissolution, this processing method provides a means for producing packaging film, medications, and medical implants with tailored release rates of active compounds. In this article, an ability to alter release rates of tocopherol, a natural antioxidant of importance to food packaging, is specifically investigated via on-line specification of a process parameter governing blend morphology in extruded cast films. Blends of low-density polyethylene and polypropylene, and also low-density polyethylene and high-density polyethylene were used. © 2009 SPE.