Investigation on preparation and properties of novel polyphenylene oxide based composites by injection molding

A novel category of polyphenylene oxide (PPO) based composites loading with different volume fractions (0, 5, 20, 35, 50 vol%) of Mg2SiO4–MgTiO3 (MSMT) ceramics was prepared by injection molding. The results showed that PPO/MSMT composites with dense microstructure and uniform filler distribution were obtained. With the increase of MSMT ceramics from 0 to 50vol%, the dielectric constant of the composite increased from 2.65 to 5.00 while the dielectric loss of it decreased significantly from 4.1 × 10−3 to 2.0 × 10−3 at 10 GHz. Increasing the testing frequency from 1 GHz to 14 GHz had little effect on the dielectric constant, but led to gradually deteriorating of dielectric loss from 1.2 × 10−3 to 2.3 × 10−3 when 35vol% MSMT ceramics were loaded. Additionally, the coefficient of thermal expansion of the PPO/MSMT composite was reduced remarkably from 76.4ppm/°C to 33.2 ppm/°C. The flexural strength of the PPO/MSMT composites is increased from 98.90 to 114.39 MPa. The novel PPO/MSMT composites prepared by injection molding process possessed excellent comprehensive properties, which are expected to be important candidates for high-frequency application in electronic packaging fields.