Preparation and Dielectric Property of Carboxyl‐Modified Polyphenylene Sulfide/Quartz Fiber/Polytetrafluoroethylene Composites

The application of pure polyphenylene sulfide (PPS) in high‐frequency devices is limited by its relatively poor mechanical properties and high dielectric constant/loss. To overcome these drawbacks, we prepared carboxyl‐modified polyphenylene sulfide (CPPS) to improve interfacial adhesion, while quartz fiber (QF) and polytetrafluoroethylene (PTFE) were incorporated to enhance mechanical properties and dielectric performance, respectively. CPPS/QF/PTFE composites were prepared and characterized by FTIR, XPS, SEM, EDS, DSC, TGA, vector network analysis, and solvent immersion tests. The composites exhibited excellent thermal stability, chemical stability, and solvent resistance. With 30 wt% QF and 30 wt% PTFE, the tensile and flexural strengths reached 131.4 MPa and 126.7 MPa, which are 121.7% and 47% higher than those of pure CPPS. The dielectric constant decreased to 2.87, slightly higher than that of pure PPS but much lower than that of pure CPPS.