Silica-containing fluorinated poly(amide-imide) hybrid films

Abstract

New silica-containing hybrid films were prepared using a fluorinated poly(amide-imide) having hydroxyl groups and tetraethoxysilane, via the sol-gel technique. The polymer was synthesized by solution polycondensation reaction of a mixture of two diamines, 4,4 0 -diamino-4 00 -hydroxy-triphenylmethane and 1,3-bis(4-aminophenoxy)benzene (molar ratio 3/7), with a fluorinated diacid chloride containing imide rings, 2,2-bis[N-(4-chloroformylphenyl)-phthalimidyl]hexafluoroisopropane. To improve the compatibility between the polymer and silica, the pendant hydroxyl groups of the polymer were reacted with 3-(triethoxysilyl)propyl isocyanate. The hybrid films were flexible, tough, and exhibited high thermal stability, having the initial decomposition temperature above 420 C. The surface morphology of the hybrid films was investigated by scanning electron microscopy. Dynamic mechanical analysis and dielectric spectroscopy revealed subglass transitions, g and b, and an a relaxation corresponding to the glass transition temperature. Electrical insulating properties were evaluated on the basis of dielectric constant and dielectric loss and their variation with the frequency and temperature. The values of the dielectric constant at 10 kHz and 20 C were in the range of 3.18-3.48. The influence of the silica content on the polymer properties was examined.

The effect of zeolite L content on dielectric behavior and thermal stability of polyimide thin films

“…Typically, three relaxation processes are observed with increasing temperature designated as c, b, and a, respectively, with a corresponding to the glass-rubber relaxation. There are some reports, which refer to the characterization and analysis of the electrical and dynamical properties of polyimide hybrid films [36][37][38][39][40][41][42][43][44]. The properties of these materials are dependent on the interphase between filler and the polymer matrix.…”

An investigation on the effects of functionalized multi-walled carbon nanotube on mechanical and thermal properties of dopamine-bearing poly(amide–imide) composite films

“…They are being used in many engineering applications such as molded parts for the space shuttle, engine parts of world-class racing cars, and many other critical components. [15][16][17][18][19] PAI can be synthesized from various aromatic monomers containing anhydride, carboxylic acid, and aromatic diamine by condensation reaction. A common synthetic route to PAIs is the amide-forming reaction from imide-containing monomers such as dicarboxylic acids or diamines.…”

Electrical properties of polyimide composite films containing TiO2 nanotubes

“…The polymer chain interactions were stronger than the interactions between inorganic particles and polymer, that can separate the polymer chains, increase the free volume and in result decrease the T g . The α relaxation peaks of the samples containing TNs, PI‐10, PI‐20 and H‐PI‐20 were broader suggesting a more heterogeneous structure . By increasing the temperature of the thermal treatment of the composite films, an increase of the T g was observed.…”