Use of various alcohols in the synthesis of foaming compositions and properties of polyimide foam materials based on them

The synthesis of foaming prepolymers based on esterified dianhydride of 3,3',4,4'-benzophenone tetracarboxylic acid in the presence of three alcohols (methanol, ethanol, isopropanol) and 4,4'-diaminodiphenylmethane was carried out. The influence of the nature of the used alcohol on the duration of dianhydride esterification and on the properties of the formed polyimide foams was shown. The process of formation of diesters of 3,3',4,4'-benzophenone tetracarboxylic acid and the structure of the resulting polyimide foams were investigated by IR spectroscopy. A comparative study of the mechanical and thermal properties of polyimide foams obtained using various alcohols was carried out. The structure of the obtained polyimide foams was studied by scanning electron microscopy. It was found that the use of methanol allows one to obtain more rigid foams, and ethanol—more elastic ones. The density of the synthesized foam materials ranged from 7.41 to 9.15 kg/m³, and the elastic modulus was equal to 39–120 kPa. All obtained foam samples demonstrate high heat resistance.