Nanocomposites production of polystyrene/silver obtained by embedding silver nanoparticles in situ with styrene polymerization

Expandable Polystyrene (EPS) is common in food packaging. The need for packaging quality fostered the development of EPS/nanosilver (AgNP) nanocomposites. In this work, a novel AgNP synthesis was performed on styrene using oleylamine as a reducing agent. The AgNP nucleation was monitored by UV–Vis and the mechanism by FTIR. The nanoparticle formation might occur through reduction from amino to imines. Bulk polymerizations were tested to evaluate the AgNP in polystyrene (PS) polymerization kinetics. To investigate the influence of AgNPs in styrene polymerization kinetics, a mathematical model of the free-radical polymerization was proposed. The total polymerization rate and free radical’s concentration decreased with increasing AgNPs concentration. Nanocomposites of polystyrene and 1.25 wt% AgNPs were synthesized by in situ suspension polymerization, adding the suspension of AgNPs in styrene before polymerization. The expansion from PS/AgNP to EPS/AgNP was successful. Although the silver amount detected in the EPS indicates a significant decrease of added silver, the desired EPS/AgNP nanocomposites were produced.