Synthesis and characterization of novel fully aliphatic polyimidosiloxanes based on alicyclic or adamantyl diamides

A series of fully aliphatic polyimidosiloxanes (APISiO) were prepared by poly(addition/condensation) reaction of bicyclo [2,2,2] oct-7-ene-2,3,5,6-tetracarboxylic dianhydride or cyclobutane-1,2,3,4-tetracarboxylic dianhydride and varying compositions of 1,3-bis (3-amino propyl)-tetra methyl disiloxane and rigid adamantyl diamines (1,3-diaminoadamantane or 3,3 '-diamino-1,1 '-diadamantane) or flexible alicyclic diamines (4,4 '-methylene bis(cyclohexylamine) or 4,4 '-methylene bis(2-methylcyclohexylamine)). High temperature one-step synthesis in m-cresol was employed to obtain APISiOs with intrinsic viscosity in the range of 0.28-0.59 dL/g. The final materials were characterized by H-1 and C-13 NMR, Si-29-MAS-NMR and IR spectroscopic analysis, thermogravimetric and differential scanning calorimetric analysis, and wide angle X-ray diffractometry. UV-visible spectra revealed the optical behavior of the polyimides. It was found that the APISiOs containing appropriate ratio of adamantyl moieties together with flexible aliphatic siloxane groups exhibit good thermal and mechanical stabilities, solubility, fair transparency, and low dielectric constant (2.4-2.7). (c) 2006 Wiley Periodicals, Inc.