Preparation and properties of polyimides having highly flexible linkages and their nanocomposites with organoclays

A highly flexible polyimide (PI) was synthesized successfully from ethylene glycol bis(anhydrotilmellitate) (TMEG) and 1,3-bis(4-aminophenoxy)benzene (TPER) for its application in electronics. To enhance the thermal stability and mechanical properties of this novel PI, we prepared PI nanocomposite films using nanoparticles of clays that had been treated with organic intercalating agents (organoclays). We used two types of organoclays: montmorillonite (MMT) treated with hexadecylamine (C-16) and MMT treated with dimethyl dihydrogenated tallow quaternary ammonium (15A). PI/organoclay hybrid films were obtained by first preparing poly(amic acid) (PAA)/organoclay films and then converting the PAA to polyimide by thermal conversion. PAA was characterized by FT-IR and H-1-NMR spectroscopy and the conversion of PAA to PI was confirmed by FT-IR spectroscopy. We analyzed the dispersion of the organoclays in the PI film by X-ray diffraction. The thermal stability and mechanical properties of the hybrid films were also investigated.