V.V. Meriakri, M.P. Parkhomenko, D.S. Kalenov, N.A. Fedoseev, Sh. Zhou
Till now the dielectric properties of nano composites based on biocompatible and biodegradable poly(ε caprolactone) (cPCL) and poly(lactic acid) polymers remain poorly investigated particularly at high frequencies.
In the present work a research of the complex dielectric permittivity of cPCL and PLA composites with nano particles of multiwall carbon nanotubes (MWNT), nano Fe3O4 and Fe3O4 absorbed MWNT is carried out in the millimeter wave range (f = 85 – 118 GHz).
For measurements a Scalar Network Analyzer working in the frequency band 78 - 118 GHz was applied. The complex parameters of a material, such as real n and imaginary κ parts of the refraction index, real e1 = n2 – κ2 and imaginary e2 = 2nκ parts of dielectric permittivity were calculated from the measured quantities of transmission and reflection coefficients of plane- parallel sample in quasi - optical set up. Measurements were carried out in the temperature interval from 20 C to 90 ºC. It was found that absorption in cPCL and PLA as well as in all nano composites increases as temperature increases in the temperature interval 30 – 45ºC for cPCL and
55 – 90ºC for PLA. Absorption in the sample of PLA with MWNT prepared with melamine was much less than in the same sample prepared without melamine.