Preparation and microwave dielectric properties of PTFE Composites Filled with Rutile Particles/Fibers

Rutile-phased TiO
₂
powders/fibers filled Polytetrafluoroethylene (PTFE/TiO
₂
) composites with well mechanical and microwave properties were prepared through mixing, calendering and hot pressing process. Herein, two types of composites include rutile-phase particles filled PTFE composites (abbreviated as RPP) and RPP composites with different contents of rutile fibers (abbreviated as RPPF). The results show that the dielectric constant of RPP composites increased sharply with gradually increasing the rutile-phased TiO2 content. In particular, the dielectric constant and dielectric loss tangent (tanδ) of RPP composites attain 10.6 and 0.00054 respectively, when rutile particles made up 52.6 wt.% (measured at 1.8 GHz), making it a promising candidate for the high-frequency applications of flexible microwave substrate. Moreover, the comparison of flexural strength between PRP and PRPF composites implies that addition of rutile-phased fiber slightly improve the flexural strength. In this paper, the rutile-phased fibers were acquired after post-heat treatment of the obtained precursor fibers by Centrifugal Jet Spinning (CJS) technique. In addition, obvious structure changes of precursor fibers after different heat-treatment temperatures were observed and characterized by X-ray diffraction (XRD).