Equal-channel angular extrusion of polymers

One of the priority lines of development of physics of polymers and material science is the development of the principles of structure modification of polymeric materials and the study of the relation between the structure and the properties, aimed to their control. Nowadays, great attention is paid to investigation of severe plastic deformation (SPD) effect on the structure modification of polymers and polymeric composites as well as to the development of the simple shear based methods of formation of orientation order. The main difference between SPD and traditional methods of pressure shaping such as die extrusion, rolling, drawing is the ability to accumulate essential plastic deformation in the processed materials. At the same time, the billet form and size are maintained and there is a possibility of development of varied deformation routes in order to generate different forms of molecular orientation. The most widely used SPD methods applied to polymeric materials are equal-channel angular extrusion (ECAE) and its modified version, so-called equal-channel multiple angular extrusion (ECMAE). The investigations carried out in research centers of USA, Japan, China, France and Ukraine showed perspectives of the use of these methods for improvement of the set of the existing physical and mechanical properties and the formation of functional properties previously unknown. In particular, in the case of semi-crystalline polymers, SPD results in increase in rigidity and strength at conserved high level of plasticity. For polymeric composites, SPD facilitates homogeneous distribution and better dispersion of the filler particles within the polymeric matrix, orientation of transition layers and polymeric matrix etc. As a result, physical and mechanical characteristics higher of those of polymeric composites without SPD were achieved.