Pre-processing of BaTiO3 nanofillers in improving dielectric response of epoxy nanocomposites at higher filler concentrations

摘要

It is well-established that the addition of very small quantities of nanosized particles into a bulk polymer can often improve its dielectric properties significantly. This is usually attributed to the large amount of interfacial material present in nanodielectrics. This work studies the effect of surface functionalizing of the nanoparticles before incorporation into the polymer matrix. Epoxy resin (Bisphenol-A) is used as a base material. High permittivity BaTiO₃ nanoparticles in the range of 90-100 nm diameter is used as filler, with the objective of obtaining a high permittivity nanocomposite. As-received as well as surface-functionalized particles are used. BaTiO₃ (BT) nanoparticles are surface functionalized with 3-glycidoxy-propyltrimethoxysilane (GPS). FESEM images of both as-received and surface-functionalized nanocomposite specimens are studied in order to check the uniformity in dispersion of the particles. The surface chemistry of BaTiO₃ nanofillers after functionalization is characterized by Fourier Transform Infrared (FTIR) spectroscopy. A Dielectric Spectroscope from Novocontrol is used to obtain the real and imaginary relative permittivity values for epoxy-based nanocomposites in the frequency range of 10-3 to 10+6 Hz. While the filler concentration does indeed influence the permittivity of the nanocomposite, it is observed that surface modification of the filler plays an equally significant role.