Ti-substituted barium hexaferrite BaFe 12 O 19 single crystals Ba-Fe 12−x Ti x O 19 with x up to 1.3 and sizes 2−8 mm were grown by spontaneous crystallization from molten sodium carbonate flux. The distribution of Ti on different crystallographic sites was determined from single crystal X-ray diffraction data. For low Ti contents up to x = 0.8 the unit cell expands; on further increase of the Ti amount the unit cell starts to shrink. This behavior for low Ti contents is most likely due to a reduction of Fe 3+ to Fe 2+ for charge balance. At higher Ti concentrations, supposedly vacancies in the transition metal substructure are formed. An increasing Ti concentration results in a monotonous reduction of the Curie temperature from 452 to 251 °C and the saturation magnetization at room temperature from 64.8 to 24.8 emu/g for powder samples and from 70.0 to 60.1 emu/g for single crystals (for x up to 0.78).

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A novel approach to design chitosan-polyester materials is reported. The method is based on mechanical activation and effective intermixing of the substrates under high pressure and shear deformation in the course of solid-state reactive blending. The marked departure of this approach from previous practice resides on exploitation of a variety of chemical transformations of the solid polymers that become feasible under conditions of plastic flow. Low temperatures (aboveTgbut below the melting points of the crystalline polymers) are maintained throughout the process, minimizing mechanical and oxidative degradation of the polymers. Morphology as well as structural, mechanical, and relaxation properties of those prepared blends of chitosan with semicrystalline poly(L,L-lactide) and amorphous poly(D,L-lactide-co-glycolide) has been studied. Grafting of polyester moieties onto chitosan chains was found to occur under employed pressures and shear stresses. The prepared polymer blends have demonstrated an amphiphilic behavior with a propensity to disperse in organic solvents that widens possibilities to transform them into promising materials for various biomedical applications.

Magnetoactive elastomers (MAEs) on the basis of a silicone matrix filled with carbonyl iron microparticles are developed for an envisaged application in eye surgery for treatment of complicated retinal detachments. The proposed magnetic fixator of an eye retina consists of an MAE seal placed inside an eye in the area of a retinal break, and an external silicone sponge with embedded permanent magnets which can be sutured to the sclera to provide magnetic field acting on the internal MAE seal. For MAE seal development, MAEs of various compositions (containing 52-76 mass% of ferromagnetic iron microparticles) are synthesized and their surface, magnetic, mechanical, and rheological properties are investigated in external magnetic fields. To demonstrate MAEs efficacy as an element of the retina magnetic fixator, magnetic forces acting between MAE samples and systems of permanent magnets were measured in the curved configuration corresponding to the human eye geometry. It has been demonstrated that the pressure produced within the fixator can be varied in a wide range by tuning the MAE composition and MAE seal dimensions as well as by optimizing the size and configuration of permanent magnets within the external silicone sponge.A high magnetic response of MAEs makes them very promising for numerous practical applications. Being a solid analogue to magnetic fluids 20 MAEs can be explored in the areas where magnetic fluids are usually used, in particular, as sealing elements, vibration absorbers, and so forth. Moreover, MAEs have some advantages in comparison with magnetic fluids, in particular, Additional Supporting Information may be found in the online version of this article.