Synthesis and properties of novel flame-retardant and thermally stable poly(amideimide) s fromN,N′-(bicyclo[2,2,2]oct-7-ene-tetracarboxylic)-bis-L-amino acids and phosphine oxide moiety by two different methods

Abstract

N,N′-(bicyclo[2,2,2]oct-7-ene-tetracarboxylic)-bis-L-amino acids3a-g were synthesized by the condensation reaction of bicyclo[2,2,2]oct-7-ene-2,3,5,6-tetracarboxylic dianhydride1 with two equimolars of Lalanine2a, L-valine2b, L-leucine2c, L-isoleucine2d, L-phenyl alanine2e, L-2-aminobutyric acid2f and L-histidine2g in an acetic acid solution. Seven new poly(amide-imide)s PAIs5a-g were synthesized through the direct polycondensation reaction of seven chiralN,N′-(bicyclo[2,2,2]oct-7-ene-tetracarboxylic)-bis-L-amino acids3a-g with bis(3-amino phenyl) phenyl phosphine oxide4 by two different methods: direct polycondensation in a medium consisting ofN-methyl-2-pyrrolidone (NMP)/triphenyl phosphite (TPP)/calcium chloride (CaCl2)/pyridine (py), and direct polycondensation in a tosyl chloride (TsCl)/pyridine (py)/N,N-dimethylformamide (DMF) system. The polymerization reaction produced a series of flame-retardant and thermally stable poly(amide-imide)s5a-g with high yield. The resulted polymers were fully characterized by FTIR,1H NMR spectroscopy, elemental analyses, inherent viscosity, specific rotation and solubility tests. Data obtained by thermal analysis (TGA and DTG) revealed that the good thermal stability of these polymers. These polymers can be potentially utilized in flame retardant thermoplastic materials.