PREPARATION AND EVALUATION OF COMPOSITES FROM MONTMORILLONITE AND SOME HETEROCYCLIC POLYMERS - 1 - POLY(N-VINYLCARBAZOLE) MONTMORILLONITE NANOCOMPOSITE SYSTEM

The cationic polymerization of N-vinylcarbazole (NVC) can be initiated directly by montmorillonite (MMT) The polymerization has been studied with MMT in solid phase and NVC at melting temperature ( > 64 degrees C) or in benzene solution at 50 degrees C. By repeated benzene extrac tion of the PNVC-MMT reaction product, an intercalcate of PNVC in MMT has been isolated. I.r. spectral analysis endorses the presence of PNV C in the intercalate. XRD analysis confirms expansion of d(001) spacin g of MMT indicating the intercalcation of PNVC in the MMT layer. TEM a nalysis indicates the particle size of PNVC-MMT intercalate to be 33 /- 10 nm. Thermogravimetric stability studies indicate, PNVC stability is much enhanced upon intercalcation confirming formation of intimate ly associated microaggregates of PNVC and MMT. Thus PNVC is completely lost around 700 degrees C but PNVC-MMT composite undergoes 19.5% loss at 999 degrees C the residue being MMT. From these t.g.a. data, it ha s been calculated that PNVC-MMT intercalate contains 6.35%. PNVC per g m of MMT. D.c. conductivity of PNVC-MMT composite (10(-6) S/cm) is 10( 10) times greater than that for PNVC (10(-16) Slcm). (C) 1998 Elsevier Science Ltd. All rights reserved.