Structure and properties of polypropylene/high-density polyethylene blends by solid equal channel angular extrusion

Solid-state extrusion of polymers using simple shear deformation

The review considers the possibilities of new methods of solid-state extrusion of polymers based on the use of deformation schemes that include simple shear - equal-channel angular extrusion, equal-channel multi-angle extrusion and combined extrusion. Information on the evolution of the physico-mechanical properties of glassy, semi-crystalline polymers, polymer blends and composites is given.

Equal channel angular extrusion of ultra-high molecular weight polyethylene

Ultra-high molecular weight polyethylene (UHMWPE), a common bearing surface in total joint arthroplasty, is subject to material property tradeoffs associated with conventional processing techniques. For orthopaedic applications, radiation-induced cross-linking is used to enhance the wear resistance of the material, but cross-linking also restricts relative chain movement in the amorphous regions and hence decreases toughness. Equal Channel Angular Extrusion (ECAE) is proposed as a novel mechanism by which entanglements can be introduced to the polymer bulk during consolidation, with the aim of imparting the same tribological benefits of conventional processing without complete inhibition of chain motion. ECAE processing at temperatures near the crystalline melt for UHMWPE produces (1) increased entanglements compared to control materials; (2) increasing entanglements with increasing temperature; and (3) mechanical properties between values for untreated polyethylene and for cross-linked polyethylene. These results support additional research in ECAE-processed UHMWPE for joint arthroplasty applications.