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.

The effect of accumulated deformation and deformation routes in the course of equal-channel multiple angular extrusion (ECMAE) on physical and mechanical properties of polyethylene (PE) differed in molecular mass (MM) has been studied. As deformation routes, route C (shear planes are parallel, and the simple shear direction of every deformation zone is changed through 180 ) and route E (shear planes are turned through 645 around the extrusion axis and the normal to the axis, and simple shear direction is changed through 180 or 690 with respect to the deformation zone) were selected. It has been shown that ECMAE provides the increase of microhardness H, modulus of elasticity E, and tensile strength r T up to 4.5 times with strain at break e b staying practically at the level of e b of the initial material. The value of the effects achieved depends on MM, accumulated deformation and the selected deformation route. The best set of physical and mechanical characteristics was observed in the case of route E. The observed effects are related to the formation of a special orientation order and increased degree of crystallinity of extrudates. According to SEM data, route C results in mostly uniaxial orientation of macrofibrils at an angle of 35 to the direction of extrusion, and formation of a part of tie fibrils and macrofibrils oriented perpendicularly to the main orientation. The route E produces biaxial orientation of macrofibrils.

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