synthesis and characterization of a new series of polyimide- nanocomposite reinforced by modified layered silicate based on 3,3′,4,4′-biphenyl tetracarboxylic dianhydride

In this research, three new reinforced nanocomposites polyimides films (9a-c) by modified organoclay (mmt) (8) varying from 1, 3 & 5 wt% were successfully prepared by in situ polymerization technique through the thermal imidization up to 200°c into a solution of n, n'-dimethyl acetamide (dmac). synthetic polyimide (4) that used as a matrix was prepared through the polycondensation reaction of 4,4´-diamino diphenyl sulfone (1) and 3,3′,4,4′-biphenyl tetracarboxylic dianhydride (bpda) (2) into n, n'-dimethyl acetamide as solvent. montmorillonite na+-organoclay (mmt) (5) was modified via a cationic exchange method by the reaction between the sodium cations of na+-mmt clay and quaternary alkyl ammonium ions of p-amino benzoic acid (6) (p-aba) as intercalation agent. resulting polyimide chains (4) diffused into the interlayer of modified organoclay layers (8) by intercalation polymerization technique. the resulting nanocomposite films (9a-c) containing 1, 3 & 5 wt% of modified organoclay prepared by casting method were characterized by fourier-transform infrared (ft-ir) spectroscopy, wide-angle powder x-ray diffraction (xrd), scanning electron microscopy (sem). results by thermo gravimetric analysis (tga) indicated shown a sharp increase into thermal stability of their nanocomposites as compared to pristine polyimide.