The influence of the mechanical activation of ZnO nanoparticle fillers on the structural and electrical properties of the matrix of poly(vinylidenefluoride)-ZnO (PVDF-ZnO) films was investigated. Transmission electron microscopy and scanning electron microscopy analyses showed that mechanical activation in a high energy planetary ball mill reduces the size of ZnO particles. X-ray diffraction and Raman spectroscopy revealed that PVDF crystallized predominantly as the -phase. Non-activated ZnO filler reduces the degree of the crystallinity of the matrix and promotes crystallization of α-phase of PVDF in the film, while the fillers activated for 5 and 10 min induce crystallization of -phase, indicating that mechanical activation of the filler can be used as a general method for fabrication of PVDF composites with increased content of piezoelectric -phase crystals.Dielectric spectroscopy measurements show that polymer composite with the high content of -phase (with ZnO filler activated for 5 min) exhibits the highest value of dielectric permittivity in 150-400 K range of temperatures. Kinetic analysis shows combined effects of increased surface area and increased concentration of surface defects on the interactions between polymer chains and activated nanoparticles.

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The investigation was performed on three woven mesh fabrics made of polyethylene terephthalate (PET), polyamide (PA) 6.6 monofilaments, and PA 6.6 with carbon filament (CF). The dielectric properties were examined as functions of frequency at room conditions and as functions of frequency and temperature under the vacuum. It was observed at lower frequency higher changes of dielectric permittivity for the sample with CFs at room conditions. For PET and PA 6.6, dielectric permittivity in the vacuum was steady and little lower; furthermore, dielectric spectra showed the existence of γ-, β-, and α-relaxations. The dc volume electrical resistivity was investigated in the function of relative humidity at room temperature for PA 6.6 and PA 6.6 with CF. For the sample with the CF, a decrease in the dc electrical resistivity of nine orders of magnitude in the direction with CF was registered as compared to the direction without a conductive filament.

The effect of the weight fraction of NaA zeolite on thermal properties (specific heat capacity, thermal diffusivity, thermal conductivity) and dielectric properties (electrical conductivity, real and imaginary electric permittivity) of composites based on low-density polyethylene (LDPE) and NaA zeolite is examined. Composite samples containing from 5 to 30 wt% zeolite are prepared using the compression molding technique. The degree of dispersion and the weight fraction of filler in the LDPE/NaA zeolite composites are determined using X-ray diffraction. A linear decrease in the values of the specific heat capacity with an increase in the weight fraction of zeolite is observed using differential scanning calorimetry. The laser flash method is used to determine the thermal diffusivity of the composites. An increase in effective thermal diffusivity and abrupt increase in the range from 15 to 20 wt% of zeolite are established. It is demonstrated that effective thermal conductivity increases with an increase in the weight fraction of zeolite, and an abrupt increase in the range from 15 to 20 wt% is observed. Dielectric spectroscopy measurements are performed to determine the real and imaginary parts of permittivity. An increase of real and imaginary parts of permittivity of LDPE/NaA zeolite composites, with increasing weight fraction of zeolite, is established. Two relaxation peaks of the imaginary parts of permittivity of LDPE/NaA zeolite composites are detected. An increase of electrical conductivity with increasing weight fraction of zeolite and abrupt increase in the range 15 to 20 wt% are noticed.