Fabrication and characterization of poly(amide-imides)/TiO₂ nanocomposite gas separation membranes
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Nanosized Ti02 rich domains were generated in-situ within poly(amide-imide) (PAl) and 6F-poly(amide-imide) (6FPAl) by a sol-gel process. The composite films showed a high optical transparency. The morphology of the Ti02 rich domains was observed by transmission electron microscopy (TEM). The Ti02 rich domains were well dispersed within the poly(amide-imide) and 6F-poly(amide-imide) matrices and were 5 nm to 50 nm in size. Limited study was also carried out for the fabrication of the P AI/Si02 and PAI/fi02-Si02 composites. It was found that nanosized Si02 rich domains were difficult to form within the poly(amide-imide) matrix, although the Si02 could be bonded with the Ti02, forming nanosized domains within the poly(amide-imide) matrix. The P AIffi02 composites showed an increased glass transition temperature, and an increased rubbery plateau modulus, in comparison to the unfilled poly(amide-imide). Wide Angle X- ray Diffraction (W AXD) study and Differential Scanning Calorimetry (DSC) analysis suggest that the Ti02 filled poly( amide-imide) have a lower crystallinity as compared to the unfilled poly(amide-imide). The dynamic mechanical properties in rubbery regions suggest that Ti02 domains function as physical crosslinks, increasing the rubbery plateau modulus with increasing Ti02 content. This behavior can be explained by the theory of rubbery elasticity. The actual formation of the nanosized Ti02 and Ti02-Si02 rich domains was explained in terms of hydrogen bonding effects between the polymer, the solvent and the inorganic components.
- Doctoral Dissertations