Abstract:
The present study investigates the dielectric and thermal properties of PTFE/Sm2Si2O7 composites. The
composites were prepared by powder processing technique followed by hot pressing. The variation of
the dielectric properties with filler content (0–0.5 Vf) was studied at 1 MHz and 9 GHz. The filler surface
was chemically modified using phenyl trimethoxy silane (PTMS) as a coupling agent. The microstructural
study using scanning electron microscopy (SEM) showed that the particles were well dispersed in the
matrix when coupled with PTMS. The surface modification led to an improvement in the dielectric properties.
The PTFE filled with 0.4 Vf silane treated Sm2Si2O7 composite showed a low dielectric loss of 0.0054
and slightly higher relative permittivity of 3.92 when compared with the untreated composite of the
same composition. The experimental values of relative permittivities were compared with the theoretical
predictions and the Effective Medium Theory was found to agree well even for higher content of silane
treated filler. It was found that the addition of silane coupling agent is very effective in improving the
thermal properties of the PTFE/Sm2Si2O7 composites
