Preparation And Proberties Of High Dielectric Constant Poly(Aryl Ether Ketone)s Matrix Nanocompisites

Driven by ever growing demands of miniaturization, increased functionality, high performance and low cost for microelectronic products and packaging, new and unique solutions in IC and system integration, such as system-on-chip (SOC) and system-inpackage (SiP), have been hot topics recently. Embedded passives will be one of the key emerging techniques for realizing the system integration. As an alternative to discrete components, embedded passives offer various advantages, including higher component density, increased functionality, improved electrical performance and reduced unit cost. Novel materials for embedded capacitor applications are in great demand, for which a high dielectric constant (k), low dielectric loss and process compatibility with printed circuit boards (PCBs) are the most important prerequisites. To date, no available material satisfies all these prerequisites and research is needed to develop materials for embedded capacitor applications. Polymer Nanocomposites as the most promising alternative materials have been studied extensively. These materials are being integrated efforts to improve dielectric properties, including the maximum increase for the dielectric constant, lower dielectric loss and to ensure the dielectric strength.In this work, poly aryl ether ketones with high dielectric strength, excellent thermal and chemical stability were selected as the polymer matrixes, then sulfonic, amino and other groups were introduced to improve their dielectric constant and the dispersion of filler material. The filling materials such as carbon nanotubes and polyaniline were modified to achieve a better dispersion in polymer matrix. In-depth reach had been carried on in order to study the effect of filler particle size, dispersion, agglomeration and other conditions on the dielectric properties of composite materials. Carbon nanotubes/polyaniline core-shell structure was obtained by in situ polymerization, and the effect of core-shell structure on the dielectric properties of composite materials had been stueied. Using percolation theory, theory of dielectric and toughening theory, this work revealed the connection between the microstructure of composite materials, and dielectric properties, mechanical and thermal properties. The main results are summarized as follows:(1) Novel a-MWNTs/NH2PAEKK nanocomposites, with a high dielectric constant, low dielectric loss and high breakdown field, were prepared by using a solution blending technique. The uniform dispersion of a-MWNTs in NH2PAEKK matrix was realized. The dependence whose dielectric properties of the composites on frequency and different volume fraction of a-MWNTs was studied. The dielectric constant of these composites firstly increased then decreased with the content of a-MWNTs. The dielectric constant of percolating nanocomposites (the a-MWNTs volume fraction of 0.09) was as high as 60 at 1000 Hz, it was about 20 times larger than the dielectric constant of NH2PAEKK, and the breakdown field was near 41.4 MV/m. The nanocomposites had tensile strength of 69.2 MPa and tensile modulus of 3.0 GPa.(2) Nanocomposites of Sulfonated Poly(Aryl ether ketone)(SPAEK) and functional multiwall carbon nanotubes (a-MWNTs) were fabricated by a solution method. The results showed that the composites exhibited a higher dielectric constant that was near 600 when the volume fraction of carbon-nanotubes was 0.07 (7 vol%) at 103 Hz. The percolation threshold of the a-MWNTs/SPAEK composites was only 3 vol% of a-MWNTs, and the dielectric constant could reach 210. The dielectric constant of composites changed little with frequency increase when the content of carbon nanotubes was more than 3 vol%, and the composites could keep high dielectric constant at high-frequency(>100, at 106 Hz). The breakdown field was near 38.4 MV/m and the energy density was 1.40 J/cm3. The nanocomposites had tensile strength of 44.7 MPa and tensile modulus of 2.2 GPa.(3) All-organic PANI-SSA/SPAEK nanocomposites with high dielectric constant and low dielectric loss were prepared by using a solution blending technique. The influence of the PANI content on the morphological, dielectric and electrical properties of the composites was investigated. The dielectric properties of composites materials was discussed by calculating the thickness of the insulating layer between the particles, and observing the changes in morphology. PANI-SSA/SPAEK nanocomposites with high dielectric constant and low dielectric loss.The composite containing 30% PANI by weight with high dielectric constant of ca.600 and low dielectric loss of ca.0.6 (at 1 kHz) was obtained. And it was able to maintain a high dielectric constant at high frequencies.(4) The a-MWNTs@PANI core-shell nanoparticles were prepared by In situ polymerization, and the mass ratio of different a-MWNTs/PANI morphology of the material was compared. Using the a-MWNTs@PANI-10 as a filling material, SPAEK as matrix material, a-MWNTs@PANI/SPAEK composites were prepared by solution blending and the performance was discussed. With a-MWNTs@PANI well dispersed in the matrix, the composites had good dielectric properties. Compared with these composites with PANI-SSA/SPAEK composites, the former had a higher dielectric constant. The introduction of PANI coating had improved a-MWNTs dispersion, limited the formation of conductive network, and reduced the dielectric loss of the composites.