Preparation, And Properties Of Aromatic Poly(Ether Ketone)s With Double-decker Silsesquioxane In The Main Chains

PAEKs,are a family of high-performance engineering thermoplastics, which have been widely used in many areas such as aerospace, electronics, nuclear industries, because of the unique combination of excellent chemical resistivity, low water sorption, thermal stability, mechanical/electrical/insulating properties.However, the traditional PAEKs generally show very low solubility toward common used organic solvents because of the high crystallinity and behave in poor hydrophobic and meantime, the dielectric constant of PAEKs(κ=3.3) should be further improved. Recently years, to overcome signal delays and crosstalk noise between the metal interconnections within integrated circuits, PAEKs with low dielectric constant are urgently demanded to satisfy the rapid development of microelectronics industry. It has been reported that PAEKs with low dielectric constant could be achieved mainly in two ways: one is to increase the molar volume by introducing bulky pendant groups, nanopores etc; another is to decrease the molar polarizability by the incorporation of the least polarizable. For the most part, the increase of the molar volume because of the nanopores or the pendant groups is the main reason for the decrease of the dielectric constant of the polymers. Among these researches, introducing polyhedral oligomeric silsesquioxane(POSS) into polymers has been considered one of the most effective ways. POSS, having an inner with an inorganic silicon and oxygen framework which is covered externally by organic substituents that can be functionalized with a variety of reactive groups making it suitable for the synthesis of POSS-containing materials. Owing to its intrinsic porosity, it has been demonstrated that polymers with POSS as chain ends, pendent groups for the main chains and grafted side chains, or even in the main chains and network all exhibited lower dielectric constant than the host polymers. Moreover, the incorporation of POSS into polymers have not only led to low dielectric but also the enhancement in the physical properties such as thermal and mechanical stability, nonflammability, oxidative resistance, low water sorption etc.A series of PAEKs containing POSS in the main chains were synthesized by a 2OH-DDSQ and the corresponding three difluorinated aromatic ketones.These polymers have remarkably improved static water contact angles, lower dielectric constants and lower water absorptions than the traditional PAEKs. In particular, DDSQ-PEEK demonstrates good combined characteristic, including low dielectric constant of 1.95 at 1MHz, high static water contact angle of 100 o, low water sorption of 0.19%; hence, it is a good candidate for low dielectric constant material against advanced microelectronic applications.