Benzocyclobutene-functionalized poly(m-phenylene): A novel polymer with low dielectric constant and high thermostability

A novel benzocyclobutene-functionalized poly(m-phenylene) was synthesized. This polymer showed good solubility and film-forming ability. When being heated at high temperature, the polymer film converted to an insoluble cross-linked network structure and did not show any cracks. Thermogravimetric analysis of the polymer film exhibited a weight loss of 5% at 547 °C and a char yield of 71% at 1000 °C in nitrogen. Moreover, the cured film had good dielectric and mechanical properties. In a range of frequencies from 0.10 MHz to 30 MHz, the cured film showed dielectric constant of less than 2.7, which was comparable with these of polyimides, polycyanates and the SILK resins. On a nano indenter system, the cured film showed an average hardness of 1.05 GPa and a Yongʹs modulus of 39.18 GPa. Those data imply that the polymer could be used as the varnish for enameled wire, sizing agents for high performance carbon-fiber, and encapsulation resins in microelectronic industry.