Synthesis and Characterization of Polybenzoxazinone and its Prepolymer Using Gas Separation

Abstract

Polybenz‐3,1‐oxazinone‐4 (PBOZ) films are prepared via the thermal rearrangement of poly[(methylene‐ bis ‐anthranilamide) 4,4′‐diphenyloxidicarboxylic acid] (PAA) films by heating to 300 °C. PAA is synthesized by low‐temperature polycondensation. The PBOZ film exhibits excellent mechanical properties and a high glass‐transition temperature. Conversion of PAA to PBOZ leads to an increase in the fractional free volume as a result of thermal dehydration and cyclization during membrane formation and due to the removal of residual solvent. The excess free volume in the PBOZ film is approximately 3–4% of the total volume. The gas permeability and selectivity of the PBOZ film is higher than that of the PAA film. The thermal rearrangement of polymers is recognized as a suitable method to improve separation efficiency. image