Fabrication And Properties Of Titanium Carbide/Polyimide Composite Films

In recent years, the high dielectric materials have obtained widelyappllication in microelectronics industry, thus it required higher performancethan before. It is well known that due to its’ very high filler contents, thetraditional ferroelectric ceramic/polymer composites had poor mechanicalproperties, which seriously impact on the application of these materials in theembedded capacitor. Therefore, the development of new dielectric functioncomposite materials with good dielectric properties and mechanical propertieshas become one of the key problems to be solved in the field of engineeringdielectric materials research.In this paper, the high conductive nanometer-size titanium carbide (TiC) wasmodified by several kinds of small organic molecules (DB570, OA and PVP),and doped as fillers into polyimide to prepare a series of the composite films withhigh dielectric properties by in-situ polymerization. The microstructure of TiC/PIcomposite films was characterized by scanning electron microscopy (SEM). Theelectrical properties and mechanical properties of TiC/PI composite films weretested. Results indicated that the distribution of TiC particles after modified bysamll organic molecules was much dense in PI matrix, with the TiC volumecontents increased. When the TiC content was less than15vol.%., the dispersityof TiC powers kept better in PI matrix. The dispersity of TiC particles modifiedby OA in composite films was better than that of TiC modified by DB570andPVP. Dielectric properties tests indicated that the TiC particle modified by PVPwas benefit for the increasement on the dielectric constant and the decreasementon the dielectric loss of TiC/PI composite films. When the TiC content reached15vol.%., the dielectric constant and the dielectric loss of PVP-modified TiC/PIcomposite films was30.95and0.0043, respectively. The TiC particle modifiedby DB570and OA was benefit for the dielectric constant increasing of TiC/PI composite films and against the dielectric loss reducing of TiC/PI compositefilms. When the TiC content reached15vol.%., the permittivity and the dielectricloss of DB570-modified TiC/PI composite films was110.05and1.1111,respectively. But the tensile strength and elongation at break of the TiC/PIcomposite films, which the OA-modified and PVP-modified TiC was added in,was higher than those of the unmodified TiC/PI composite films. When the TiCcontent was20vol.%., the tensile strength of OA-modified and PVP-modifiedTiC/PI composite films was86.30MPa and85.71MPa, and the elongation atbreak of those composite films was5.51%and5.78%respectively. With the TiCpowders volume content increased, the electric breakdown field strength of threekinds of TiC/PI composite films was shape dropped. When the TiC content was20vol.%., the electric breakdown field strength of DB570, OA-modified andPVP-modified TiC/PI composite films was11.24kV/mm,12.17kV/mm and10.87kV/mm, respectively.