Preparation and properties of polyimide/aluminum nitride composites

Polyimide/aluminum nitride (AlN) composites based on pyromellitic dianhydride (PMDA) and 4,4'-oxydianiline (ODA) were prepared by in situ polymerization. To disperse the AlN particles in the polyimide matrix homogeneously, gamma-glycidoxypropyltrimethoxysilane (GPTS) was used as coupling agent for the preparation of the composites. It was found that, with the inclusion of aluminum nitride powder into the polyimide matrix, the thermal properties of the resulting polyimide-AlN composite were improved without obvious loss in the dielectric properties. The results indicated that the thermal stability and the thermal conductivity of the composite were enhanced, while the dielectric constant increased slightly and the electrical properties altered to less degree with the increase of AlN fraction. Meanwhile, the dielectric and thermally conducting properties were also influenced by the content of the coupling agent. In addition, the thermally conducting and dielectric properties of the studied composites followed the classic composite theories. (C) 2004 Elsevier Ltd. All rights reserved.