Synthesis of polyamide-imides with different monomer sequence and effect on transparency and thermal properties

Mechanically Robust and Transparent Polyamideimide Films via Consecutive Polycondensation, Amidation, Acid Removal, and Bluing Agent Addition

“…Halo signals observed in a wide-angle region are due to the π–π stacking structure of the aromatic rings in the backbone, indicating that all of the polymers are intrinsically amorphous. Similar observations have been reported for other polyamideimides. − Relatively strong signals are also observed at around 13.37° (6.63 Å) for I 1.0/1.0 , 15.70° (5.66 Å) for II 0.7/1.0/0.3 , and 15.19° (5.85 Å) for II 0.5/1.0/0.5 and II 0.3/1.0/0.7 . These values correspond to the average distance between highly twisted polymer chains owing to the steric hindrance of the bulky CF 3 groups.…”

Polyamide-imide/polyimide alloy with enhanced energy density and efficiency

“…The characteristic peaks located at 1776, 1711, 1368, and 721 cm À1 correspond to the CQO asymmetric stretching, CQO symmetric stretching, C-N stretching, and imide ring deformation of PI, respectively. 42 The absorption peaks at 1782, 1720 (CQO asymmetric stretching, CQO symmetric stretching), 1667 cm À1 (CQO symmetric stretching of amide), 1370 cm À1 (C-N stretching), 1252 cm À1 and 1152 cm À1 (SQO asymmetric stretching, SQO symmetric stretching), respectively, demonstrate the successful synthesis of PAI. In addition, the characteristic absorption peaks of the PAI/PI alloy indicate its successful fabrication.…”

Reduced coefficient of linear thermal expansion for colorless and transparent polyimide by introducing rigid-rod amide units: synthesis and properties

“…To further research the origin of the relatively high transparency and dimensional stability of the films, the molecular chain aggregation structures of the PAIs were studied by 2D-GIWAXS. 34,35 The 2D-GIWAXS data and the corresponding structural information for in-plane and out-of plane directions are displayed in Fig. 7.…”