Preparation and characterization of novel basic polysulfone polymers

Two synthesis routes for the preparation of novel base-modified polysulfone s (PSUs; Udel((R))) were investigated: (1) the addition of the basic aromat ic ketones 2,2 ' -dipyridylketone and 4,4 ' -bis-(diethylamino)benzophenone and the basic aromatic aldehydes N,N-dimethylamino-benzaldehyde, pyridine- 2-aldehyde, pyridine-3-aldehyde, and pyridine-4-aldehyde to lithiated PSU a nd (2) the reaction of lithiated PSU with basic aromatic carboxylic acid es ters such as 4-N,N-dimethylaminobenzoic acid ethylester, pyridine-2-carboxy lic acid ethylester, pyridine-3-carboxylic acid ethylester, and pyridine-4- carboxylic acid ethylester. Both synthesis routes lead to a high degree of conversion, without the occurrence of crosslinking. This is remarkable, esp ecially for the reaction of lithiated PSU with the ester compounds, because the - (C=O)-Ar groups formed by the reaction of the ester with PSU-Li are not further converted with the remaining PSU-Li sites to (crosslinked) PSU- C(-OLi)-Ar-PSU alcoholates, as normally observed when esters are reacted wi th Li-organic compounds. Starting with dilithiated PSU, we obtained degrees of substitution of 0.8-2 groups per PSU repeating unit. The structures and compositions of the modified PSU polymers were confirmed with NMR spectros copy and elemental analysis. The modified polymers were also characterized via thermogravimetric analysis (thermal stability). Interestingly, the prod uct of the reaction of lithiated PSU with 4,4 ' -bis-(diethylamino)benzophe none could be oxidized to a deep blue polymeric dye that showed proton self -conductivity. (C) 2001 John Wiley & Sons, Inc.