Rubber-ceramic composites applicable in flexible antennas

Abstract

Glass ceramics from the CaO–P2O5–SiO2 system were synthesized. They were characterized by XRD, SEM and EDX methods. It was found that they contain two crystalline [Whitlockite, Ca3 (PO4)2 and Hydroxylapatite, Ca5 (PO4)3 (OH)] and one residual amorphous phase. The ceramics are composed of porous aggregates of fine particles with predominant macro- and mesopores in it. The ceramics were used as a functional filler in natural rubber based composites, as the filling is in the range of 5–50 phr. The influence of the chemical nature and structure of the ceramics and the degree of filling on the vulcanization characteristics, physicomechanical parameters, dielectric and dynamic properties, the coefficient of thermal conductivity and the volume resistivity, including external pressure or bending on the specimens were investigated. An influence of the filler and the degree of filling on all studied properties was found. All tested composites have dielectric parameters (ε′, real part of complex permittivity; ε′′, imaginary part of complex permittivity; σ, conductivity; tanδɛ, tangent from dielectric loss angle) suitable for use as substrates and insulating layers of flexible antennas. Particularly impressive are composites containing 30 and 50 phr fillers, which have the lowest tangent from dielectric loss angle values.

The role of chemical microstructures and compositions on the actuation performance of dielectric elastomers: A materials research perspective

“…[ 130 ] Similarly, modifications of BT and other dielectric fillers (e.g., TO) were extensively studied in combination with NR to yield satisfactory electro‐mechanical sensitivity. [ 131 ]…”

Three‐phase bio‐nanocomposite natural‐rubber‐based microfibers reinforced with cellulose nanowhiskers and 45S5 bioglass obtained by solution blow spinning

“…As a method of improving and enhancing biomedical properties of NR-based nanocomposites, the use of bioactive particles, such as glass-ceramics and bioactive glasses (BG), has been explored. [31][32][33] Among the BGs, those with SiO 2 , CaO, Na 2 O and P 2 O 5 in their composition are considered highly bioactive, and the first one glass used in this capacity and possessing such properties was discovered by Hench et al 34 ; it is commercially called 45S5. As the gold standard of bioactive materials, the 45S5 BG has the highest bioactivity index (IB = 12.5).…”

Comprehensive experimental investigations and theoretical predictions on the physical properties of natural rubber composites

“…Commonly used conducting fillers are carbon nanotubes, carbon dots, graphene, metal fillers and its oxides, and conductive carbon black (CCB). [10][11][12][13][14][15][16][17] Among the above-mentioned fillers, CCB is conventionally used as reinforcing filler. CCB is the widely used filler in natural rubber (NR) matrix because it is cost-effective material and can improve the conductivity and thermo-mechanical properties of NR based composites.…”

“…Conductivity in insulating rubbers can be achieved by the formation of a continuous network of conducting fillers in the rubber matrix. Commonly used conducting fillers are carbon nanotubes, carbon dots, graphene, metal fillers and its oxides, and conductive carbon black (CCB) 10–17 . Among the above‐mentioned fillers, CCB is conventionally used as reinforcing filler.…”