Potentialities of a new simple shear-based scheme of the solid-phase extrusion of polymers, named the equal channel multiple angular extrusion (ECMAE), for modification of semicrystalline polymer structure have been investigated by the example of low-and highdensity polyethylene (LDPE, HDPE), polyamide-6 (PA-6), and polytetrafluoroethylene (PTFE). The effects of velocity and extrusion temperature, plastic deformation intensity, and accumulated equivalent plastic strain value on properties of a number of crystallizing polymers have been studied. It has been shown that the highest strength characteristics are attained for the extrusion temperatures of (0.8-0.95) of the melting temperature and deformation velocity of (0.6-1.1) mm s 21 . For the ECMAE-processed specimens, the density, the enthalpy, and the melting temperature have become higher. In the oriented structure of semicrystalline polymers formed by the ECMAE, the lamellae are oriented along the extrudate axis.

Deformation routes of equal‐channel multiple angular extrusion (ECMAE) are suggested that allow realization of new combinations of positions of planes and directions of simple shear. The routes are called F, B+C, D+C. Their effect on the structure and the properties of semicrystalline polymers is studied by the example of high density polyethylene, polyoxymethylene, polytetrafluorethylene. It is demonstrated that the enhanced strength and plasticity characteristics and the reduced anisotropy of microhardness in longitudinal and transversal directions are achieved in the series: route C → routes E,F → route B+C → route D+C. The methods of X‐ray structure analysis and dilatometry revealed differences in biaxial oriented fibril structures formed after these ECMAE routes have been applied and in the character of their distribution over preferred directions of orientation. Possibility of realization of bidirectional invar‐effect in rod‐shaped billets is presented. POLYM. ENG. SCI., 54:531–539, 2014. © 2013 Society of Plastics Engineers

Theoretical chemistry Z 0350 The Shape Memory Effect in Polymers -[205 refs.]. -(BELOSHENKO, V. A.; VARYUKHIN, V. N.; VOZNYAK, Y. V.; Russ. Chem. Rev. (Engl. Transl.) 74 (2005) 3, 265-283; Galkin Donetsk Physicotech. Inst., Natl. Acad. Sci. Ukr., Donetsk 340114, Ukraine; Eng.) -Lindner 37-291

International audienceOne 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