Investigation on the improvement of microwave dielectric properties of plasma-prepared fluoropolymer-coated CaTiO3-filled PTFE composites

High-performance polymer matrix composites preparation has been urgently hampered by poor interfacial adhesion between two phases. In this article, a thorough analysis of the microstructure and overall properties of composites made of polytetrafluoroethylene filled with fluorocarbon polymer film-coated CaTiO3 was conducted. The similar fluorocarbon molecular structure of CaTiO3 surface and PTFE provides a bridge between the two, significantly improving and promoting the microstructure and interface adhesion of the composite. The comprehensive properties of modified composites are obviously superior to those of untreated composites. Composites filled with 30 wt% CaTiO3 have an excellent dielectric constant at 5.53, acceptable dielectric loss at 0.0047, an outstanding heat resistance index of 281.1°C, and relatively low hygroscopicity of 0.10%. At the same time, the mechanical properties are maintained at a high application level, which makes them promising for microwave devices.