Mechanical, thermal and microwave dielectric properties of Mg2SiO4 filled Polyteterafluoroethylene composites

Polytetrafluroethylene (PTFE)-Mg2SiO4 composites have been prepared using both micron and nano-ceramic fillers by hot pressing. The dielectric properties of the composites are investigated both at radio and microwave frequency ranges as a function of filler loading up to 50 vol%. The dielectric constant and loss tangent increases with filler volume fraction. The composite with 50 vol% micro-filler has a dielectric constant of 3.2 and loss tangent 0.009 at 5 GHz with Vickers microhardness 16 HV. The surface of ceramic particles was modified by silane treatment. The surface modification reduced porosity and moisture absorption and improved the microhardness. The CTE of the composite decreased and thermal conductivity increased with filler loading. Nanopowders of Mg2SiO4 has also been prepared by sol-gel method and composite has been made with PTFE. The nanocomposite has higher moisture absorption, dielectric constant and loss tangent but lower CTE value. The PTFE Mg2SiO4 composites are possible candidate for microwave substrates applications. (C) 2016 Elsevier Ltd and Techna Group S.r.l. All rights reserved.