Synthesis of polyvinyl pyridine ferrite nanocomposites in supercritical carbon dioxide

A supercritical carbon dioxide (scCO₂) assisted process was developed to synthesize polyvinyl pyridine ferrite na-nocomposites (PvPyFN). The process involved synthesis of polyvinyl pyridine (PvPy) through rheoviscometrically monitored polymerization of 4-vinyl pyridine in presence of benzoyl peroxide under various reaction conditions in supercritical carbon dioxide (scCO₂), followed by infusing ferrite nanoparticles into PvPy matrix at 1:2, w/w in scCO₂ at 3000 psi, 40±1°C for 1.0 hr. This has afforded corresponding PvPyFN comprising volume concentration of ferrite nanoparticles into PvPy matrix ranging 0.563-2.043.The variation of rheoviscosity with molecular mass of PvPy was investigated through gel permeation chromatography. The ferrite nanoparticles were synthesized through treating different concentrations of FeCl₂. 4H₂O with ammonia solution at 80±1°C. The size of ferrite nanoparticles was calculated according to Debye Scherrer method and was found in the range of 11-20 nm. The formation of PvPyFN was ascertained through Uv-vis, FT-IR, XRD, Laser induced break down spectra, vibration sample magnetometry and scanning electron microscopy. All such PvPyFN were formed as chelate of ferrite with tertiary nitrogen of PvPy and comprise heterogeneous morphology, super paramagnetic characteristics with saturation magnetization ranging 15.2-35.8 emu/g.