A Study on the Fabrication Parameters and Dielectric Properties of PTFE Composites Filled with Al₂O₃ and SiO₂ Nanoparticles

Abstract

In order to fabricate and enhance the composites with dielectric functions, printed circuit boards (PCBs) were made from polytetrafluoroethylene (PTFE) gel after curing with 350°C. SiO2 and Al2O 3 nanopowders were used as the fillers and PTFE was the matrix used to fabricate the composites. A proposed stirring machine was used to conduct the compounding process, which can assist in the uniform distribution of nano-Al2O3 and nano-SiO2 powders in PTFE. The PTFE gel was mixed in the proposed stirring machine. Following stirring, molding and calendaring were done to release air bubbles and to increase the surface uniformity and smoothness of PCBs. Finally, PCBs were fabricated after cooling and sintering processes. Several kinds of PCBs were made by varying a wide range of fabrication parameters which included: percentage of particles added, size of particles added, different fabrication procedures, rotational speeds of the stirring machine, sintering, and cooling temperature, and calendaring times. Influences of these parameters and fabrication conditions on the dielectric properties of PCBs were investigated. This study established that there are some fabrication parameters due to which we get the worst dielectric properties of PCBs. Therefore, the optimum fabrication conditions and affecting factors of the board were investigated. As a result of this research, it was concluded that both dielectric constant and loss factor of the board were decreased by the addition of SiO2 and Al 2O3 nanoparticles and the optimum rotational speed of stirring machine is 3000 rpm. Dielectric properties of PCBs were increased at speeds above 3000 rpm.