Direct Synthesis of Thermally Stable Semiaromatic Polyamides by Bulk Polymerization Using Aromatic Diamines and Aliphatic Dicarboxylic Acids

Semiaromatic polyamides were directly synthesized by bulk polycondensation of aliphatic dicarboxylic acids (with 5, 6, 7, and 10 carbon numbers) and aromatic diamines (4,4'-oxydianiline and 4,4'-diaminodiphenylmethane) under natural pressure. In addition, copolyamides were successfully obtained by the copolymerization of aliphatic dicarboxylic acids, aromatic diamines, and biobased amino acid, 4-aminohydrocinnamic acid. The obtained polyamides had relatively high inherent viscosity values of 0.35-0.76 dL/g. The obtained polyamides exhibited good thermal stability with T-d5% in the range of 316-416 degrees C, even when incorporated with aliphatic methylene units. In particular, some copolyamides (2AO, 2PO, and 2GM) had high T-g values of 150, 158, and 156 degrees C and relatively low T-m values of 277, 288, and 234 degrees C, respectively, which may be preferable thermal properties for melt-drawing processes.

Automated summary

Semiaromatic polyamides were synthesized by bulk polycondensation, and copolyamides were successfully obtained. The obtained polyamides had high inherent viscosity and good thermal stability, and some copolyamides were suitable for melt-drawing processes.