Synthesis and properties of polyamides and polyesters containing 2,5-thienylene lingkage

Abstract

Polyamides and polyesters containing 2,5-thienylene linkage were synthesized by the interfacial polycondensation of 2,2-bis-(5-chlorocarbonyl-2-thienyl) butane and 2,2-carbonyl-bis-(5-thiophene carboxylic acid chloride) with various diamines and diols in water-dichloromethane solvent at room temprature in the presence of sodium hydroxide as an acid acceptor. The structures of these polymers were identified by IR and H$^1$-NMR Spectroscopy. Characteristic absortion bands of polyamides appeared at $3650-3150 cm^{-1}$ (N-H stretching), $1660-1615 cm^{-1}$ (amide I band), and $1560-1520 cm^{-1}$ (amide II Band) and those of polyesters were observed at $1745-1725 cm^{-1}$ (carbonyl stretching of ester group). The physical properties of these polyamides and polyesters were also investigated. The resulting polyamides had inherent viscosities in the range of 0.3-0.62 dl/g and those of polyesters were 0.08-0.24 dl/g. These polymers revealed relatively good thermal stability. The TGA data showed 10\% weight losses of polyamides at $330-492\,^\circ\!C$ and those of polyesters at $342-507\,^\circ\!C$.