Synthesis and study of the effect of carboxyvinyl group position on the properties of polyamides. Crosslinked polymers

Several aromatic polyamides containing carboxyvinyl bonds in the main chain were synthesized by self-condensation from β-(2-,3-,4-aminophenyl)propenoic acid using the phosphorylation method. In addition, aromatic polyamides containing carboxyalkyl bonds in the backbone were synthesized under the same conditions for comparative purposes (model polyamides) and used as pattern. The model polyamides were synthesized from 3-,4-aminophenyl acetic acid and β-(3-aminophenyl)propanoic acid. Polymers were characterized by UV–vis, FT-IR and ¹H-NMR spectroscopy, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and inherent-viscosity measurement. The effect of the carboxyvinyl group position in the aromatic ring was correlated to polyamides properties. Thereby, solubility, thermal stability, viscosities, optical properties, and polymers crosslinking were studied. Some polyamides were soluble in polar solvents and inorganic acids. Upon thermal curing crosslinked polymers were obtained. The thermal stability and crosslinking of polyamides were evaluated with respect to position of carboxyvinyl in the aromatic ring. The crosslinked polymers exhibited improved thermal stability.