Hyperbranched polyimide-silica hybrid materials: Synthesis, structure, dynamics, and gas transport properties

摘要

A series of organic-inorganic hybrid materials were prepared from a hyperbranched polyimide precursor (hyperbranched polyamic acid), tetramethoxysilane, and/or 3-glycidyloxypropyl-trimethoxysilane via a sol-gel process. The hyperbranched polyimide-silica hybrids, whose polyimide moieties were based on commercially available monomers 4,4,4-triaminotriphenylmethane and 4,4-oxydiphthalic anhydride taken in molar ratio 1:1, contained from 10 to 30wt% silica. Their morphology and dynamics were characterized by using scanning electron microscopy, differential scanning calorimetry, dynamic mechanical analysis, laser-interferometric creep rate spectroscopy, and wide-angle X-ray diffraction. Attention was also focused on the relation between morphology/dynamics and gas transport properties of these materials.