Fabrication and Characterization of Polyimide/AlN Nanocomposite Films

Polymers with good insulating properties are widely used in motors, rotating machines and components in power electronics and microelectronics1-3. It is well know that polymer properties can be greatly improved by adding inorganic fillers to form composite polymer. Polyimide has been a polymer of choice in many areas owing to its excellent dielectric properties, high thermal mechanical strength and toughness4-7. Aluminum nitride (AlN) has a reasonably high electrical resistivity (>1014 Ω·cm) and a small relative permittivity (about 8.0) which is close to that of many polymer matrices and much smaller than that in other ceramics. It also has good heat transfer characteristics which the coefficient of thermal expansion is 3.5×10-6 /°C8. The favorable properties of AlN would make it a good inorganic filler material in insulating polymers in power, microelectronic and power electronic industries.