Synthesis of phosphine sulfide group-containing aromatic poly(ether)s with aliphatic substituents on the phosphorus atoms and low dielectric properties

Recently, materials with low dielectric properties have attracted particular attention because low dielectric properties are key factors in realizing next-generation communication devices with high-speed and low-loss signal transmission and processing and electronic components with high electrical breakdown voltages. In this study, phosphine sulfide (P=S) group-containing aromatic poly(ether)s with aliphatic substituents on the phosphorus atoms were developed for use as low dielectric materials, taking advantage of the low polarity of the P=S groups and the less polarizable nature of the aliphatic moieties. These polymers have moderate to high molecular weights (number-average molecular weights of 8900–35,000 and weight-average molecular weights of 31,900–178,000), good thermal stability (5% weight loss temperatures of 363–423 °C), and high glass transition temperatures (T_g = 210–219 °C). In addition, some of the polymers exhibited low dielectric constants (ε = 2.64–2.68 at 10 GHz and 2.56–2.59 at 20 GHz) and low dielectric dissipation factors (tanδ = 0.0034–0.0035 at 10 GHz and 0.0036–0.0037 at 20 GHz). These results may indicate that P=S group-containing aromatic poly(ether)s with high aliphatic contents are potentially applicable to electrically insulating materials with good dielectric properties in the GHz frequency range and could contribute to high-performance electronic devices.