Value-added materials made from recycled plastics

A novel, economical Solid-State Shear Extrusion (SSSE) pulverization process is being further studied for development of blends derived from recyclate. This process uses a modified co-rotating, ZE-25 twin-screw extruder, manufactured by Hermann Berstorff Maschinenbau, GmbH. The first machine of this design is currently in operation at the Polymer Reclamation Center at Northwestern University. The SSSE-pulverization process converts mixed post-consumer or post-industrial waste into powders. Work done to date was primarily focused on mixed polyolefins. Evidence has been obtained for the in-situ formation of graft and block copolymers which may serve as compatibilizers.(1,4,7). Several blends of post-consumer high density polyethylene (HDPE), linear low density polyethylene (LLDPE) and polypropylene (PP) at different ratios have been pulverized with ZE-25 extruder. When these powders are molded into parts, the mechanical behavior is found to be substantially better than that of materials produced with typical recycling operations. The continued development of SSSE process offers opportunity to solve the current post-consumer waste plastics disposal problem by creating value-added materials made from recycled plastics.(2-6).