Effect of Morphology on the Relaxation Processes and Mechanical Properties in Polyimide/Silica Hybrids

Polyimide/silica hybrids were produced by a sol-gel process and were examined in terms of their morphology, dynamic-mechanical properties and mechanical performances. Two types of morphology were obtained by tailoring the composition of the precursor solution mixture, i.e. phase- separated or co-continuous systems. These morphologies were found to exhibit considerably different properties. In particular, co-continuous nanocomposite systems were found much more effective in suppressing molecular relaxation processes than micron sized particulate hybrids. The latter systems, on the other hand, exhibited enhanced ductility and fracture toughness