Synthesis and Characterization of Aromatic Polymers Containing Pendant Silyl Group. II. Aromatic Polyamides

Abstract

In order to improve the solubility of aromatic polyamides without significant loss of thermal stability, synthesis of aromatic polyamides containing pendant silyl groups was carried out by direct polycondensation of silylated aromatic diacids such as 2-trimethylsilylterephthalic acid (TSTA), 2,5-bis(trimethylsilyl)terephthalic acid (BTSTA), 5-trimethylsilylisophthalic acid (TSIA), 5-dimethylphenylsilylisophthalic acid (DMSIA), and 5-triphenylsilylisophthalic acid (TPSIA) with various aromatic diamines. The resulting polyamides had inherent viscosities in the range of 0.18-1.10 dL/g and showed improved solubilities toward aprotic polar solvents such as NMP, DMF, DMSO, etc. The prepared aromatic polyamides exhibited fairly good thermal stabilities, which were almost comparable to those of corresponding nonsubstituted aromatic polyamides. That is, thermogravimetric analysis (TGA) data revealed 10% weight losses at 358-500-degrees-C and residual weights at 700-degrees-C were 46-67% under nitrogen atmosphere.