Improved properties of PTFE composites filled with glass fiber modified by sol–gel method

PTFE/GF(glass fiber) composites are widely applied in high-frequency printed circuit board (PCB) substrate materials due to the excellent dielectric properties of PTFE and low thermal expansion coefficient GF. However, poor interface compatibility between GF affects performance composite substrates. In this study, tetraethyl orthosilicate (TEOS) was used as silicon source, polydimethylsiloxane (PDMS) organic precursor modify surface through sol–gel method promote PTFE. The modified noted T-GF filled prepare PTFE/T-GF composites. SEM, FTIR, XPS, contact angle confirmed that organic–inorganic hybrids were successfully loaded on GF's surface. Moreover, compared with PTFE/GF conventional coupling agent composites, exhibited improved constant (2.305), decreased loss (9.08E?4), higher bending strength (21.45 MPa) modulus (522 MPa), better conductivity (0.268 W/m*K) lower CTE (70 ppm/°C), making it has promising application for high frequency PCB.