| Abstract: | Molecular aggregation in polytrimellitamideimide (PAI) was investigated by small-angle x-ray scattering (SAXS). PAI films annealed above the glass transition temperature show a scattering peak characteristic of two-phase structure. A one-dimensional model was used to analyze these SAXS curves. The more ordered phases are produced at higher annealing temperature. The average thickness of the ordered lamellae is comparable with the repeating length of the main chain. The relative difference of electron density between two phases is only a few percent, which shows that the two-phase structure of PAI, like that of aromatic polyimide, differs essentially from that of ordinary crystalline polymers. |
