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The effect of orientation of the layers of the original structure of polymers produced by fused deposition modeling (FDM) on the reinforcing effect caused by succeeding equal channel multiple angular extrusion (ECMAE) is studied. As test objects, glassy acrylonitrile butadiene styrene copolymer (ABS), glycol-modified poly(ethylene terephthalate) (PET-G) and semicrystalline PET are selected, as well as layered composites ABS/PET and ABS/PET-G. It is demonstrated that ECMAE results in enhancement of microhardness, storage modulus, impact strength. The density, the glass transition temperature, the melting temperature are increased, too. The crystallinity degree of extrudates is enhanced. It is shown that an increment in the mechanical characteristics is better in the case of longitudinal position of the melt layers, as compared to the transversal one. The achieved effects are related to the pore healing, formation of orientation ordering, and enhanced interphase interaction and homogenization of the system in the course of production of layered composites of thermodynamically incompatible polymers. A physical model is suggested that describes the behavior of the layered materials under ECMAE. [ABSTRACT FROM AUTHOR]

Radio-frequency magnetic and dissipative properties of La0.6Sr0.2Mn1.2O3 and La0.65Sr0.28Mn1.07O3 ceramics have been studied in the region of their Curie points. It is established that, despite relatively high conductivity in the frequency range f = 1–15 MHz, the screening of samples by the skin current is negligibly small and the ceramic samples behave like strong ferromagnets. This behavior is explained by significant differences in the propagation of electromagnetic field in inhomogeneous granular ferromagnetic media and normal metals. The field dependence of the effective magnetic susceptibility of both manganites has been studied at room temperature. © 2004 MAIK “Nauka / Interperiodica”. [ABSTRACT FROM AUTHOR]