Phase Transfer Catalyst Stabilized Metal Nanoparticles for Free Radical Polymerization

Abstract

A new catalytic approach in the free radical polymerization reaction of acrylonitrile (AN) using K₂S₂O₈ as a water soluble initiator in biphase medium was established using cetyltrimethylammonium bromide (CTAB) as conventional PTC and MNPTC’s. The three types of homogeneous metal nanoparticle catalyst (MNPTC) viz., CTAB-RuNpsC, CTAB-AuNpsC and CTAB-AgNpsC were synthesized using CTAB as a common stabilizing agent and respective metal salts as their precursors. The formations of these metal nanoparticles irrespective of the metal catalysts were confirmed with FT-IR, UV-VIS and TEM techniques. The kinetic study of the polymerization reaction using CTAB as PTC was carried out initially to find the steady state rate of polymerization and the order of the reaction. After fixing the steady state rate as 50 mins and other parameters like concentration of monomer, initiator and temperature as constant, the comparative catalytic activities of the catalyst were examined. From the observed rate of polymerization (Rp) the order of activity of catalyst were determined as CTAB-RuNpsC > CTAB-AuNpsC > CTAB-AgNpsC >> CTAB. Further, the image of the acrylonitrile polymer formed from the CTAB-RuNpsC catalyst was studied using FESEM microscope. On the basis of the obtained results, a mechanism is proposed for the polymerization reaction.