Solid‐State Extrusion

Abstract

A brief information is given on solid‐state extrusion (SSE), a method for the attaining a high‐oriented state of polymers, which is based on polymer deformation at temperatures just below the polymer melting point, or for amorphous polymers just above the glass‐transition temperature mainly by pressing through conical or slit dies. SSE is used for shape forming and structure modification of various polymer materials (homopolymers, polymer blends, filled polymer composites) and makes it possible to produce fibers, films, pipes, shapes including those of large cross section and different configurations, possessing high strength stress characteristics. In the paper, the most known SSE versions are considered: These are plunger extrusion and hydrostatic extrusion with the information on the influence of process controlling parameters in the structure and the properties of the processed material. New techniques of SSE are analyzed: These are equal‐channel angular and multiple angular extrusion, twist and planar twist extrusion, which, in contrast to the conventional ones, are based on polymer simple shear, not drawing. The data about specific features of realization of these methods are reported as well as structure evolution and physical and mechanical properties of the processed polymer materials of different structures: glassy and semicrystalline polymers, polymer mixtures, and filled composites.

Модифікація Полімерних Матеріалів Інтенсивною Пластичною Деформацією

“…1, б) применяется для создания ориентированной структуры, способствующей получению изделий с высокими деформационно-прочностными параметрами. По сравнению с традиционными способами твердофазной экструзии полимеров -плунжерной и гидростатической экструзией [15], реализация которых сопровождается уменьшением поперечных размеров исходной заготовки, РКУЭ позволяет осуществлять молекулярную ориентацию без формоизменения. При этом появляются новые возможности управления структурным состоянием, связанные с многообразием геометрии оснастки, условий и маршрутов деформирования.…”

Micromanufacturing by severe plastic deformation

“…The consequences for materials processed by SPD in terms of their mechanical properties are remarkable, as their initial grain structure is reduced in a spectacular way -down to deep submicron scale, and in some cases to nanoscale [3,4]. Not only are such techniques suitable for providing bulk materials with an ultrafine-grained (UFG) structure, but they can also be efficient for consolidation and 'cold sintering' of metal powders [5], solid-state modification of polymers [6,7], recycling of machining chips [8,9], and other engineering applications.…”

Improvement of mechanical properties of polylactide by equal channel multiple angular extrusion

“…This approach has been successfully applied for number of polymers, such as, polyethylene, polypropylene, polyoxymethylene, polyamides, polytetrafluoroethylene, polyethylene terephthalate, polycarbonate, polymethylmetacrylate, poly(L-lactic acid). 26 Besides the self-reinforcing effect, solid state extrusion could cause phase transition, re-structurization of the crystal lattice and in some cases substantial changes in the conformation of polymer chains. [26][27][28][29] In the present work, equal channel multi angular extrusion (ECMAE) was selected as a solid state extrusion method that affects PLA microstructure through extreme uniform simple shear.…”

“…26 Besides the self-reinforcing effect, solid state extrusion could cause phase transition, re-structurization of the crystal lattice and in some cases substantial changes in the conformation of polymer chains. [26][27][28][29] In the present work, equal channel multi angular extrusion (ECMAE) was selected as a solid state extrusion method that affects PLA microstructure through extreme uniform simple shear. 30,31 A peculiarity of ECMAE compared with equal channel angular extrusion is that several zones of shear deformation are present within one device permitting the accumulation of high plastic deformation per one cycle.…”