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°C) or in benzene solution at 50°C. By repeated benzene extraction of the PNVC-MMT reaction product, an intercalcate of PNVC in MMT has been isolated. I.r. spectral analysis endorses the presence of PNVC in the intercalate. XRD analysis confirms expansion of d₀₀₁ spacing of MMT indicating the intercalcation of PNVC in the MMT layer. TEM analysis 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 intimately associated microaggregates of PNVC and MMT. Thus PNVC is completely lost around 700°C but PNVC-MMT composite undergoes 19.5% loss at 999°C the residue being MMT. From these t.g.a. data, it has been calculated that PNVC-MMT intercalate contains 6.35%. PNVC per gm of MMT. D.c. conductivity of PNVC-MMT composite (10^-6 S/cm) is 10¹⁰ times greater than that for PNVC (10^-16 S/cm).