Synthesis and Characterization of Novel Polyimides from 1,1-bis[4-(4-aminophenoxy)phenyl]-1-(4-hydroxyphenyl)ethane

Abstract

A new diamine, 1,1-bis[4-(4-aminophenoxy)phenyl]-1-(4-hydroxyphenyl)ethane, was synthesized in three steps starting from 1,1,1-tris(4-hydroxyphenyl)ethane. New aromatic polyimides having hydroxy side groups were prepared from this diamine and various tetracarboxylic dianhydrides by the conventional two-step procedure that included ring-opening polymerization in N-methyl-2-pyrrolidone (NMP) and subsequent thermal cyclic dehydration. The polyimides were characterized by X-ray diffraction, differential scanning calorimetry (DSC), thermogravimetry (TG), and dynamic mechanical analysis (DMA). All the polyimides were amorphous, and had glass transition temperature ( Tg) in the range of 232—304 °C. The properties of polyimides were compared with those of polyimides prepared from 1,1-bis[4-(4-aminophenoxy)phenyl]-1-phenylethane, which had no hydroxy side groups. The effects of the hydroxy side groups were observed in the thermal properties, thermal mechanical properties and solubility of polyimides.