Transparent polyimide nanocomposite films: Thermo-optical properties, morphology, and gas permeability

Poly(amic acid) (PAA) hybrids with organically modified montmorillonite (Cloisite 30B) were synthesized from N,N′‐dimethylacetamide (DMAc) solution. These hybrids were heated at various temperatures, yielding 64‐ to 68‐μm thick films of polyimide (PI)/Cloisite 30B hybrids with various clay contents (0–1.5 wt%). The intercalation of PI chains among the organoclay particles was examined using wide‐angle X‐ray diffraction (XRD) and electron microscopy (TEM) techniques. The thermo‐optical properties were measured by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and ultraviolet‐visible (UV–vis) spectrometry. The optimum thermal and oxygen barrier properties were observed for the hybrids containing 1.0 wt% Cloisite 30B; these properties were degraded gradually by further increases in the clay content. The presence of only 1.0 wt% Cloisite 30B in a PI hybrid film was found to result in an 83% reduction in the rate of O2 permeability with respect to that of the pure PI film. The PI hybrid films were found to exhibit excellent optical transparency and to be almost colorless. However, the transparency of the hybrid films decreased slightly with increasing organoclay content. POLYM. ENG. SCI., 2011. © 2011 Society of Plastics Engineers