Synthesis and Characterization of New Polyamides with Substitutions in the Pendent Benzylidene Rings

Abstract

Aromatic polyamides with azomethine groups present in the polymer with -Cl, -OCH 3 , -N(CH 3 ) 2 and -OH substitutions in the pendent benzylidene rings were synthesized through polycondensation of new aromatic dicarboxylic acids with aromatic diamines using the phosphorylation technique in DMF. Direct polymerization of the monomers benzylidenamino phenyl 2,5-dicarboxylic acid (M1), 4 -hydroxy benzylidenamino phenyl 2,5-dicarboxylic acid (M2), 4 -methoxy benzylidenamino phenyl 2,5-dicarboxylic acid (M3), 4 -chloro benzylidenamino phenyl 2,5-dicarboxylic acid (M4) and (N,N-dimethylamino) benzylidenamino phenyl 2,5-dicarboxylic acid (M5) was carried out with commercial diamines, 4,4 -methylenedianilene and 4,4-diaminobiphenyl, at 140 • C. FT-IR and 1 H-NMR spectroscopic analysis were used to characterize the monomers and polymers. The inherent viscosity values of polyamides are in the range 0.39-0.68. Due to the substitutions in the pendent benzylidene rings, the polymers show enhanced solubility. The thermal stability of the polyamides was evaluated using thermogravimetric analysis, and the thermogravimetric curves show the dependence of thermal stability on the nature of the substitutions in the benzylidene rings.

Synthesis, Characterization and Metal Ion Adsorption Studies on Novel Aromatic Poly(Azomethine Amide)s Containing Thiourea Groups

“…Introduction of carbon-nitrogen double bonded azomethine units into a polymer backbone not only enhances the thermal stability, semi conductivity but also improves protonation and complexation ability [2][3][4]. Poly(azomethine amide)s reported so far mainly focussed to improve the polymer solubility, thermal stability and liquid crystalline properties [4][5][6][7][8]. Inclusion of phenylthiourea groups into polymer backbone has gained great importance for its excellent properties such as corrosion resistance, thermal stability, semi conductivity and binding to metal ions [9][10][11].…”

Synthesis, characterization, and heavy metal ion adsorption studies of polyamides, polythioamides having pendent chlorobenzylidine rings

“…The synthesis of this modified terephthalicacid monomer (2) was carried out according to the earlier reports 13. The IR spectra of 4‐aminoterephthalic acid and that of the monomer 2‐( p ‐chlorobenzalimino) terephthalic acid (2) are shown in Figure 1.…”

“…This modified terephthalic acid was prepared according to our earlier report 13. A solution of 4‐aminoterephthalic acid (0.01 mol) and chlorobenzaldehyde (0.01 mol) in DMF (50 mL) was mixed in a 250‐mL round‐bottomed flask with catalytic amount of p ‐toluenesulfonic acid, and the contents were heated to 110°C.…”

“…On the basis of the aforementioned advantages of azomethine and phenyl thiourea groups, it is of interest to synthesize new generation of polymers containing these groups in the polymer backbone. Earlier works from this laboratory where aimed at synthesis of poly (azomethine ester)s12 and poly (azomethine amides)s 13. Such polymers show good corrosion control on Al in alkaline medium,14 and good conductivity when blended with different poly anilines 15…”

Synthesis and Characterization of Some New Thermally Stable Crystalline Polyamides and Co-Polyamides Bearing Bipyridine Side-Chain Groups

“…Wholly aromatic polyamides (aramids) are high-performance polymeric materials with outstanding mechanical properties and excellent thermal and chemical stabilities due to chain stiffness and intermolecular hydrogen bonding of amide groups [1][2][3][4][5][6][7]. However, the processing of these polymers by thermoplastics methods has been extremely difficult because in many cases they do not melt below their decomposition temperature and moreover they are insoluble in organic solvents [8][9][10][11].…”