Synthesis and characterization of poly (4vp- co-dvb)/montmorillonite nanocomposites by in situ intercalative polymerization

Abstract

“4-Vinylpyridine” (4vp) crosslinked with 2% divinylbenzene (dvb) polymer [poly (4vp- co-dvb)]/OMMT (organically modified montmorillonite) nanocomposites were synthesized by in situ intercalative suspension polymerization. Sodium montmorillonite (SMMT) with a cation exchange capacity (CEC) of 90 meq/100 g was organically modified (OMMT) by the intercalation of cetyl “trimethylammonium” bromide (CTAB). The intercalation of CTAB into montmorillonite was confirmed from the expansion in basal space of the layered silicate from 1.5 to 2.0 nm as detected in the XRD (X-ray diffraction) pattern. OMMT was subsequently used as host along with the monomers for the preparation of polymer nanocomposites. It was found that OMMT was easily intercalated by 4vp and dvb to form a stable crosslinked polymer/clay intercalated hybrid. The nanocomposites were examined by means of XRD, transmission electron microscopy (TEM), scanning electron microscopy (SEM), thermal gravimetric analysis (TGA), and differential scanning calorimetry (DSC). Thermal stability of the nanocomposites increased as compared to the pure polymer. It was observed that the spherical shape of the pure polymer beads disappeared on composite formation as evidenced by SEM.