Preparation and properties of novel aromatic polyimides from 4,4'-diamino-4'-hydroxytriphenylamine and aromatic tetracarboxylic dianhydrides

摘要

Novel aromatic polyimides containing hydroxytriphenylamine units were prepared from 4,4'-diamino-4"-hydroxytriphenylamine 1 and various aromatic tetracarboxylic dianhydrides 2.The glass transition temperatures (T_g s) of these polyimides were in the range of 274-388 deg C and the 10% weight loss temperatures (T_(d_(10))s) were above 462 and 511 deg C in air and nitrogen respectively.Polyimide 4f prepared from diamine 1 and 4,4'-hexafluoroisopropylidenebis(phthalic anhydride)(6FDA) was soluble not only in organic solvents such as N-methyl-2-pyrrolidone,N,N-dimethylacetamide,N,N-dimethyoformamide,1,3-dimethyl-2-imidazolidone and dimethyl sulfoxide but also in tetramethylammonium hydroxide aqueous solution.Other resulting polyimides were not soluble in organic solvents.The resulting polyimides 4 possessed T_g s about 20-70 deg C higher and poorer solubilities than the previously reported polyimide prepared from 4,4'-diaminotriphenylamine and various aromatic tetracarboxylic dianhydrides.These results indicated that polymer properties such as thernal behaviour and solubilities were influenced by the intermolecular interaction of hydrogen bonding due to hydroxy units.