Preparation of Silver Nanoparticles by Using Tripropylene Glycol as the Reducing Agents of Polyol Process

Silver (Ag) nanoparticles were prepared by the polyol process using tripropylene glycol, 3-ethyl-3-oxetanemethanol, and polycaprolactone triol as the reducing agents and poly(vinylpyrrolidone) (PVP) with average molecular weights (Mw) of 10 000, 55 000, and 1 300 000 as the protective agent, respectively. It was found that the sizes of Ag particles were affected by the type of reducing agent, Mw of PVP, the concentration of PVP, reaction temperature, and time. The Ag nanoparticles as small as 34.4 nm were achieved when the reaction was conducted at atmospheric ambient and a temperature of 120 °C for 3 h by using tripropylene glycol as the reducing agent and 20 wt.% PVP with an Mw of 55 000. The nanoscale Ag particles with face-centered cubic structure exhibited a strong surface plasmon resonance peak at 350 nm in the UV-visible spectrum.