High silica fiberglass cloth/PTFE composites: Interfacial bonding and dielectric property enhancement

Abstract In this study, high silica fiberglass cloth (HSFC) was prepared using the acid leaching method with E‐fiberglass cloth as the raw material. Following heat treatment and silane coupling agent treatment, the cloth was impregnated with a polytetrafluoroethylene (PTFE) emulsion to fabricate a HSFC/PTFE composite via the hot‐pressing method. The microstructure of the composite and its dielectric properties at a 10 GHz frequency was investigated. To address the interfacial bonding issue of the composite, pre‐sintering treatment and silane coupling agent application were employed, resulting in reduced porosity and increased density of the composite. In particular, the composite treated with KH‐570 silane coupling agent exhibited the lowest porosity, with a dielectric constant of 2.419 and a dielectric loss of 0.0049. This study offers a new direction for expanding the application of high silica glass clothes in high‐performance glass fiber composites. Highlights A low dielectric composite was made from high silica fiberglass and polytetrafluoroethylene. Heat treatment reduced hydroxyl groups on the fiberglass surface. Surface modification enhanced interfacial bonding and dielectric properties. Pre‐sintering removed impurities and reduced composite porosity. Lower porosity reduced the dielectric loss of the composite.