Microwave dielectric properties of SrAl2Si2O8 filled Polytetrafluoroethylene composites

摘要

The properties of Polytetrafluoroethylene (PTFE) filled with SrA12Si208 (SAS) and alkali-free glass fiber (GF) were investigated. The content of GF is 1 vol. %, and the content of SAS varied form 10 vol. % to 50 vol. %. The SAS was modified by silane coupling agent to improve interaction between SAS and PTFE, and the composites were prepared through SMECH (include Sigma Mixing (SM), Extrusion (E), Calendering (C) and Hot pressing (H) ) process. XRD was used to testify the phase purity of SAS. FTIR was used to analyze the surface of modified SAS. The SAS/PTFE composite material exhibited a near-zero dielectric constant temperature coefficient (τε=5.1 ppm/°C) while achieving a low dielectric constant (e,.=3.21) and a low dielectric loss (tanδ<5=0.00136) at 40 vol. % SAS filling. The SAS/PTFE composites are potential candidates for microwave substrates applications.