Preparation and evaluation of a poly(N-vinylcarbazole)–Fe3O4 (PNVC–Fe3O4) nanocomposite

N-vinylcarbazole (NVC) was polymerised in bulk in presence of nano sized Fe3O4 and a nanocomposite of poly (N-vinylcarbazole)–Fe3O4 (PNVC–Fe3O4) was isolated from the system. The yield of the PNVC–Fe3O4 composite increased with increasing time of polymerization as well as with [Fe3O4]/[PNVC] loadings. A charge transfer initiation of NVC polymerization was proposed which was followed by cationic propagation and monomer termination. The formation of PNVC was confirmed by FTIR, UV–vis, emission and 1H1 NMR spectroscopic analyses. TGA and DTA analyses revealed a much higher thermogravimetric stability for the PNVC–Fe3O4 composite in contrast to PNVC. HRTEM studies revealed that the PNVC–Fe3O4 nanoparticles have an average grain size of 32 nm and that the Fe3O4 nanoparticles are fairly well-dispersed in the composite matrix. SEM analysis showed the presence of agglomerates of nano particles embedded in the matrix. XRD patterns for PNVC, PNVC–Fe3O4 composite and Fe3O4 particles were analyzed by constructing a Williamson–Hall plot from which particle size for the composite was estimated to be 34 nm in good agreement with the HRTEM value. The saturation magnetization value of the pure nano sized Fe3O4 was 6.98 J kg−1 T−1 at 300 K while those for the composites were 3.08 and 2.21 J kg−1 T−1 at 300 K for two different [Fe3O4]/[PNVC] loadings. σac-frequency variation was constant for PNVC but showed an increasing trend with higher Fe3O4:PNVC weight ratios in the composite.

► A nanocomposite of poly (N-vinylcarbazole) and nano-dimensional Fe3O4 was prepared by in situ solid state polymerization.
► The composites showed higher thermo gravimetric stability compared to the base polymer.
► Fe3O4 nanoparticles fairly well-dispersed in the composite matrix.
► Ac conductivities varied with weight ratios of [Fe3O4]/[PNVC] and frequency and the trends were indicative of contributions from free charges and trapped charges in the composite.