Epoxy Nanocomposites with Metal-Containing Fillers: Synthesis,Structure, and Properties

Russian Journal of Applied Chemistry - Recent achievements in the field of the development of preparation methods and study of structure and properties of epoxy nanocomposites with metal-containing...     

Diagnostics of the Phase Composition of Lead-Zirconate-Titanate Films according to Raman Spectra: Phase Identification

The problem concerning the diagnostics of the phase composition of lead-zirconate-titanate (PZT) films under conditions of overlapping Raman spectra is solved via applied mathematical statistics. The proposed phase-identification method based on reference spectra is implemented using different Raman-spectrum regions measured on the surface of multiphase PZT films. It is demonstrated that the identification of phases, as well as determination of their concentration, must be performed using the spectral range in which the calculated first principal components of the set of Raman spectra differ to the greatest extent from each other.     

High-Speed Composite Microactuator Based on Ti<Subscript>2</Subscript>NiCu Alloy with Shape Memory Effect

Samples of microactuators are made of a bimorph composite of Ti₂NiCu alloy with a thermoelastic martensitic transition and the shape memory effect, and their response rate is investigated. The active layer of the composite actuator is a layer of the rapidly quenched Ti₂NiCu alloy, pseudoplastically prestretched, and an amorphous layer of the same alloy is used as an elastic layer. Typical sizes of the microactuator are 30 × 2 × 2 μm. The controlled amplitude of the displacement of the microactuator tip is approximately 1 μm. The response rate of the microactuator was investigated by scanning electron microscopy. Activation of the microactuator was achieved by heating when electric pulses were passed through it. Full activation of the microactuator at frequencies up to 1 kHz was demonstrated; partial activation was observed at frequencies up to 8 kHz. The possibility of operating the device in a self-oscillating mode at frequencies of the order of 100 kHz is demonstrated.     

Modification of epoxy polymers with small additives of multiwall carbon nanotubes

The effect of small additives of functionalized multiwall carbon nanotubes used as a modifier on the formation and properties of epoxy polymers cured with diaminodiphenyl sulfone is investigated. In the range of additive concentrations 0.01–0.50 wt %, there are extreme dependences of dynamic storage modulus and the glass-transition temperature on modifier concentration. As shown by electron microscopy and X-ray scattering, regions with increased packing densities of macromolecules are formed in the polymers in the presence of the modifier. The effect of the specific surface on the kinetics of curing of epoxy resins is observed. A mechanism controlling the formation of the epoxy matrix that is responsible for the inhomogeneous polymer structuring that defines the final properties of the polymers is suggested.     

Estimation of topological structure of epoxycarbonate systems formed on amine-curing without heat supply

The effect of active cyclocarbonate-containing modifying agents on the topological structure of epoxyamine templates is considered. The estimation of the topological structure and the adequacy of the real process are presented.     

X-ray topography analysis of bulk acoustic wave resonators

X-ray topography is first used to totally examine the fundamental modes of acoustic oscillations in the bulk-acoustic-wave (BAW) resonator on the base of an AT-cut quartz crystal at the first and third harmonics. As is evident from the experiments, the anharmonic longitudinal oscillations of the resonator can be visualized, just as the fundamental transverse acoustic oscillations can be. The amplitude-frequency response (AFR) is related to the frequency dependence of diffracted x-ray intensity.     

Studying acoustic-wave fields in langasite-family crystals using the BESSY II synchrotron radiation source

The process of the excitation and propagation of pseudosurface acoustic waves in crystals of the langasite family is studied via X-ray diffractometry for the first time. The investigations are carried out using the BESSY II synchrotron radiation source in the double-crystal X-ray diffractometer scheme. The process of pseudosurface acoustic wave propagation is studied based on an analysis of the diffraction spectra of acoustically modulated crystals. Both the velocities of the pseudosurface acoustic waves and the power flow angles of the acoustic energy are measured for the first time. The pseudosurface acoustic wave is shown to be flowing. Surface and pseudosurface acoustic waves generated by an interdigital transducer in the Z cut of a La₃Ga_5.5Ta_0.5O₁₄ crystal are compared.