Clean and dry route of synthesis of C 60 /polyvinylpyrrolidone composite using supercritical carbon dioxide

In the present investigation, we have studied polymerization of (a) vinylpyrrolidone (VP) and (b) VP with C60 molecule applying various supercritical conditions with 2,2-azobisisobutyronitrile (AIBN) as a catalyst. Products hence obtained are polyvinylpyrrolidone (PVP) and fullerene-polyvinylpyrrolidone (C60/PVP) polymers. With polymerization reaction, the yield of corresponding C60–PVP polymers was significantly affected under applied concentrations of AIBN (304.5–1218.0 × 10−3 mol/dL) supercritical pressure (1200–1800 psi), temperature (C60 90 ± 1°) and time (3–6 h). The concentration of VP ranged 7.04–12.59 × 10−3 mol/dL. The samples of the synthesized C60/PVP polymer with lowest (24.8%) and highest (45.0%) yields were characterized using UV–Vis, FT-IR, 1H NMR, laser-induced breakdown spectra, scanning electron microscopy and simultaneous TG–DTA–DSC. The morphology of the C60/PVP polymers was confirmed by scanning electron micrographs which indicates the existence of separated C60 phases with heterogeneous morphology in corresponding C60/PVP polymers in all the cases. Simultaneous TG–DTA–DSC revealed enhanced thermal stability of C60/PVP.